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ACS Applied Polymer Materials (26376105) (3)
Soft robots with intelligent shape-changing capabilities and spatially controlled actuation are essential for enhancing their performance. Here, three-dimensional printing of self-healing, near-infrared light-responsive shape memory granular hydrogels (SLSH) was introduced. The hydrogels were formulated using four distinct microgels: β-cyclodextrin-functionalized microgels (CDMGs) and 1-adamantylamine-functionalized microgels (AMGs) to promote host-guest physical interactions for self-healing and shear-thinning properties; polydopamine-functionalized microgels (PMGs) for photothermal conversion and antibacterial activity; and microgels with epoxy groups (MG) to enable chemical cross-linking with Jeffamine, forming a shape memory framework. The shear-thinning, shape memory, and self-healing characteristics were influenced by physical interactions within the ink as well as the chemical bonds formed after postprinting treatment. The viscosity and yield strength of the inks showed an increasing trend with a higher fraction of CDMG and AMG, indicating stronger reversible attractions within the jammed assembly of particles. Upon irradiation with an intensity of 1000 mW·cm-2 for 2 min, the internal temperature of the hydrogels increased to 38.2-43.0 °C, depending on the hydrogel type. For SLSH70, a distinct melting peak was recorded at 35-41 °C, associated with the melting of crystalline domains of Jeffamine, which was essential for the thermal shape recovery of the construct. After 1 h of fixation, the hydrogels SLSH30, SLSH50, and SLSH70 demonstrated a shape-fixing efficiency of 98.22 ± 0.45, 99.38 ± 0.68, and 98.54 ± 0.26%, respectively, with shape recovery efficiency approaching approximately 100%. During the self-healing process, complete reattachment occurred after 24 h at 25 °C for SLSH30, while the other samples exhibited a weaker healing ability. Finally, the results of antibacterial investigations highlighted the synergistic effects of PMG’s inherent antibacterial properties and its photothermal activity within the bacterial environment. © 2025 American Chemical Society.
Polymer Composites (02728397)
Waterborne polyurethane (WPU) is one of the most applicable products used in various industries to manufacture smart coatings with self-healing ability due to its being environmentally friendly. However, the self-healable WPU coatings suffer from long healing times, low transparency, and poor physicochemical properties. Herein, ionic nanocomposite coatings were prepared based on SiO2-nanoscale ionic materials (SiO2-NIMs) and novel WPU, with fast self-healing ability, high transparency, and UV-blocking performance. We demonstrate that SiO2-NIMs can significantly act as a unique healing agent in the WPU due to their fluid 3D-dynamic networks of hard core-corona (SiO2-SO3−) and soft segments (canopy). The optical micrographs show the WPU film containing 3 phr SiO2-NIMs completely repaired after 20 min at 50°C. The tensile test illustrates that elongation at break, tensile strength, and toughness values of the healed sample recovered 78.2%, 94.2%, and 69.3% of the original film, respectively. The differential scanning calorimetry, x-ray diffraction, and dynamic mechanical-thermal tests were applied to confirm core-corona-canopy segments' hardening and excellent damping behavior in the WPU matrix. The thermogravimetric and tensile analyses demonstrate that SiO2-NIMs can enhance the thermal stability and mechanical properties of WPU. This study introduces a novel strategy based on SiO2-NIMs for preparing self-healing polymers with outstanding physicochemical properties. Highlights: Synthesized novel WPU based on anionic Congo red. Introducing a novel strategy-based SiO2-NIMs for self-healing of coatings. Enhancement of self-healing and thermo-mechanical properties of the WPU. Introducing healable and UV-blocking abilities of ionic nanocomposite coating. © 2025 Society of Plastics Engineers.
Biomaterials Advances (27729508)
Herein, Polydopamine-modified microgels and microgels incorporated with superficial epoxy groups were synthesized and applied as precursors for the fabrication of four granular hydrogels. To enhance the tissue adhesiveness, a ternary deep eutectic solvent was synthesized to activate the muscle amine functional groups facilitating the formation of robust N–C bonds at ambient conditions. At a certain shear rate of 10 s−1, hydrogel DMG displayed a viscosity of 9×103 Pa/s, representing the highest complex viscosity among the tested hydrogels primarily driven by quinone groups in PDA which enhanced reversible interactions, thereby increasing particle cohesion. Moreover, the intersection point escalating from about 4×103 to approximately 9×104 as the concentration of DMG increased from 0 % (for MG) to 70% (7D3MG) by weight. There was a decrease in adhesion strength from 0.45 ± 0.08 N in MG to 0.39 ± 0.16 N, 0.35± 0.18 N, and 0.33 ± 0.15 N for 3D7MG, 7D3MG, and DMG respectively, suggesting that MG was capable of forming numerous covalent bonds, thereby enhancing its adhesion to the substrate. The type of eutectic mixture affected the electrical conductivity and a very important point was the changes in resistance value with time. For MG catalyzed by [DES]AZG, the resistance increased only by 1.3 % (from 3.37 to 3.81 kΩ) at day 3 and 37.09 % (from 3.37 to 4.62 kΩ) at day 5. The 3D7MG hydrogel exhibited superior therapeutic efficacy toward diabetic wound regeneration. The proliferation index value for 3D7MG-[DES]AZG and 3D7MG-[DES]AG were calculated 42.3 % and 58.6 %, respectively, while the control group exhibited a lower value of 37.8 %. © 2024 Elsevier B.V.
Polymer Composites (02728397) 46(9)pp. 7858-7881
Epoxy resins (EP), as significant thermosetting macromolecules, are widely used in various engineering applications due to their wide range of properties. However, the poor control over curing process of EP, limits their manufacturing process. Here, a SiO2-nanoscale ionic materials (SiO2-NIMs)/EP nanocomposite was prepared. The Friedman, Kissinger, Ozawa, Málek, and Friedman autocatalytic models were used to determine kinetic parameters and reaction models, which demonstrates that the SiO2-NIMs improve the curing characteristics of EP through an exclusive mechanism. The solvent role of SiO2-NIMs decreased viscosity and increased reactant mobility, leading to increased curing reactivity. The multi-function groups in the corona-canopy make multiple hydrogen bonding and proton transfer interactions in EP resin, leading to the autocatalytic curing mechanism and effectiveness of treatments. The frequency factor of EP increased by 9% with the addition of SiO2-NIMs. The differential scanning calorimetry tests revealed that SiO2-NIMs decreased Tonset and Tpeak compared to EP. The non-isothermal rheometric mechanical spectrometery (RMS) test indicated that SiO2-NIMs decreased the Tgel of EP resin from 75 to 71°C and increased the initial storage modulus by 90.9%. This study introduces SiO2-NIMs as significant fillers to enhance control over the process conditions and curing kinetic of EP resin for advanced applications such as aerospace and satellite industries. Highlights: Introducing new catalyst based on 3D-dynamic networks strategy of SiO2-NIMs. The SiO2-NIMs show great potential in improving curing characteristics of EP. The SiO2-NIMs increase the frequency factor of EP by 9%. The RMS test indicated SiO2-NIMs increased initial storage modulus by 90.9%. The Fourier transform infrared spectroscopy analysis indicated that SiO2-NIMs accelerate curing process of EP. © 2025 Society of Plastics Engineers.
Polymer Bulletin (01700839) (15)
Deep eutectic solvents have attracted considerable attention due to their economic and environmental benefits. This study investigates the role of reactive DESs in the synthesis of polyurethane coatings. DESs synthesized from Tetrabutylammonium bromide (TBAB) as a hydrogen-acceptor and Poly (ethylene glycol) and Ascorbic acid (AA) as hydrogen-donors, were used as assistant platforms and reactive agents for the synthesis of new biodegradable crosslinked PU-coatings via a solvent-free process. Cured PUs were characterized by FTIR, DSC, TGA, and DMTA techniques, as well as gel-content, swelling-index, biodegradation, scratch, and hardness tests. The results show that these DESs have played a splendid multi-task role that acted as non-volatile solvents and reactive monomers as well. They also facilitated curing reaction, improved flexibility, biodegradability, swelling-index, and resistance to scratch of PU-based DESs compared to pristine PU. PU samples synthesized in the presence of [DES]PEG/TBAB (P2) and [DES]AA/TBAB (P3) showed increased flexibility and damping properties (78, 26 Shore D—0.9, 1.3 Tanδ), biodegradability (81%, 60%), swelling-index (105%, 150%) and scratch resistance (3.8, 4.5 N), by about 69%, 52%, 36%, 48%, and 26% compared to the control sample (P1), respectively. Agar diffusion tests showed antibacterial activity of PU-DESs against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. This research highlights DESs as promising platforms to enhance the properties of PU coatings for the creation of eco-friendly, high-performance antiseptic coatings. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
Chemical Engineering Journal (13858947) 471
Epoxy (EP) adhesives as high-shear strength permanent adhesives have been used in various engineering applications, particularly aerospace and automotive. However, these adhesives suffer from disadvantages such as high fragility, poor tensile strength, and toughness, which limits adhesion efficiency in structural bonding. Here, a novel EP nanocomposite adhesive-based SiO2-nanoscale ionic materials (SiO2-NIMs) with excellent adhesives strength, transparency, thermal stability, and mechanical properties was prepared via a solvent-free process. To prepare SiO2-NIMs, the sulfonated-SiO2 nanoparticles (SiO2-SO3H) were ionically tethered as a core-corona with Jeffamine-ED-2003 chains as a canopy. Then, SiO2-NIMs/EP nanocomposites with various SiO2-NIMs contents were fabricated. We demonstrate that SiO2-NIMs as high-performance additives, unlike conventional additives, via an exclusive mechanism can simultaneously improve interfacial bond strength, stiffness, and toughness of EP adhesive. The RMS and DMTA tests averred the liquid-like SiO2-NIMs played a magnificent multi-functional role that acts as nonvolatile solvents, reinforcing-agent particles, and toughening agents, causing improved shear strength and resistance to crack growth of epoxy adhesives. The core-corona-canopy parts of SiO2-NIMs make hydrogen bonds and ionic-electrostatic interactions between the adhesive and adherent layers. The single lap shear under different temperatures, TGA, tensile, and SEM tests were applied to investigate adhesion strength, thermal and mechanical properties, and fracture surface morphology of EP adhesives, respectively. For example, the 5 phr SiO2-NIMs/EP showed increased lap shear strength at RT, tensile toughness, tensile strength, stiffness, elongation% and char-yield% by 54%, 240%, 92%, 36%, 91%, and 50% compared to neat EP, respectively. This study introduces SiO2-NIMs as promising additives for high-performance EP adhesives. © 2023 Elsevier B.V.
Polymer Bulletin (01700839) (9)
Designing new drug delivery systems (DDSs) with appropriate performance and tunable release properties for targeted cancer treatment is still a topic of interest. Waterborne polyurethanes (WPU)s are versatile materials for this purpose. However, they need to hybrid with natural polymers to improve their biodegradability. New pH-sensitive folate-targeted peptide-based PEGylated nanocarriers utilizing biodegradable WPUs with tunable bioactivity were designed for paclitaxel (PTX) delivery in this work. Enjoying different structural designs of WPUs through changing block arrangement and synthesis strategies, we adjusted degradation and different aggregation morphologies of water-dispersed nanocarriers comprising micelles, nanoparticles (NPs), or core–shell NPs. The effectiveness of these structural designs was studied completely in vitro. Their hydrodynamic size and zeta potentials range 148–470 nm and − 8 to − 23.5 mV, respectively; two formulas with micellar and core–shell nanoparticular characteristics were selected as the best candidates (PEU2-PEG-FAend micelles with a hydrodynamic size of 251 nm, ZP about − 16.1 mV, and CMC value of 0.024 mg/mL; PEU2@PEG-FA core–shell NPs with a hydrodynamic size of 153 nm and ZP of about − 23.5 mV). Benefiting from the precise design and sequencing of structural segments and the bioactivity of Ser and LCP, these synthetic nanocarriers exhibited reasonable biodegradation rate, cytocompatibility, and blood compatibility. Core–shell NPs showed the highest loading capacity for PTX (LC% was 44) and the most controlled release among all studied nanostructures. In vitro release studies showed that the drug-loaded nanocarriers (PEU2-PEG-FAend micelles and PEU2@PEG-FA core–shell NPs) have a sustained release feature at acidic pH of 5.5 to about 100% within 72 h. The IC50s of nanomicelles (49.5 μg/mL) and core–shell NPs (32.5 μg/mL) were lower than free PTX (69.5 μg/mL). Finally, flow cytometry results approved better internalization of targeted micelles (99.6% versus 87.6%) and core–shell NPs (100% versus 73.5%) than non-targeted ones into HeLa cells via endocytosis. These nanocarriers would be promising targeted anticancer DDS to guarantee adequate drug concentration to kill the cancer cells and avoid multi-drug resistance. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Additive Manufacturing (22148604)
Additive manufacturing technology is a growing field, which demands advanced chemistry and fabrication process if smart-materials are desired. Herein, the concept of jammed microgels designed with a new crosslinking method is introduced to be used in 3D-printing applications. Jammed microgels decorated with superficial hydrophobic segments and pure thermo-sensitive gelatin are applied as inks and exhibit shear-induced transition and fast recoverability, which are important for 3D-printing. The interaction of microgels within the as-extruded filaments and with the adjacent deposited layers guarantees shape-fidelity. After printing, a deep eutectic solvent (DES) formed from Arginine and Glycerol ([DES]Arg/Gly) is applied over the construct to trigger a chemical crosslinking reaction between epoxy and amine groups. The introduced [DES]Arg/Gly can play simultaneously two roles: (1) activator of covalent bond formation and (2) conducting agent. Generally, a variety of features including printability, rheological properties and shape-retention are dependent on the fraction of hydrophobic segments and the applied [DES]Arg/Gly concentration. Further, the main network percolation reaction follows a different strategy to achieve a sustainable printable system with biological, mechanical and physiological sustainability of the construct. These results open new possibilities to fabricate a wide range of adaptive platforms of smart materials with ease. © 2022 Elsevier B.V.
Carbohydrate Polymers (01448617)
In this research we focused on the fabrication of an asymmetric bilayer membrane with core-shell/simple layer configuration providing the functions of needed hierarchically hydrophilicity and porosity, anti-infectious, tissue adhesion as well as degradation and integration with tissue, cells proliferation, and enhanced promotion of tissue regeneration. The bilayer membrane composed of collagen (Col), chitosan (CS), aloe vera (AV) and gelatin (Gel), not only simulates the features of the epidermis and dermis layer of a natural skin but also benefits from the materials necessary for the regeneration of injured skin tissue during the healing process. The results of full-thickness skin wound evaluation revealed that the fabricated asymmetric membrane could facilitate wound healing within 10 days mainly through enhancing cellular activities, enhancing collagen deposition, and promoting proliferation. Results of histopathological analysis and immunohistochemistry after 10 days of treatment, demonstrated more re-epithelialization and collagen density for the treated groups compared to the control group. © 2022
Journal of Molecular Liquids (01677322)
Many engineered epoxy products in the recent years require sustainable materials to be contributive in the coming decades. The efficiency of [DES]Arg/Eg and [DES]Glu/Eg deep eutectic solvents (DESs) on the curing reaction of bisphenol A diglicydyl ether (DGEBA) with the application of differential scanning calorimetry (DSC) at temperatures 313–333 K is assessed. The both DESs studied here can act as the catalyst of epoxy-amine reaction, hardener and conducting agents in a simultaneous manner. Moreover, it reveals different reaction kinetics which strongly depend on the type of hydrogen bonding acceptor of the mixture. It is observed that there exist many fundamental differences between the progress of isothermal curing reaction in the presence of [DES]Arg/Eg and [DES]Glu/Eg considering the conductive ionic liquids and non-conductive conventional hardeners. The [DES]Glu/Eg at lower concentrations exhibits different catalytic behavior in the initial stages of the reaction, in a sense that the reaction progresses at higher rates up to 5 min and hampered afterward. In contrast, [DES]Arg/Eg act as a high-efficient catalyst in a sense that it allows the curing reaction approaches the completion level within 30 min which is comparable to previously reported conducting dopants. From kinetic results it is deduced that the mechanism of curing reaction follows the first-order kinetic in the presence of [DES]Arg/Eg and [DES]Glu/Eg and reaction occurring in the presence of [DES]Glu/Eg is characterized by higher activation energy compared to [DES]Arg/Eg. To analyze the efficiency of DESs as a catalyst for the epoxy-amine reaction, a computational study is run on a simplified model reaction catalyzed by [DES]Glu/Eg revealing a significant decrease in activation energy of the catalyzed reaction. © 2021 Elsevier B.V.
Iranian Polymer Journal (10261265) (10)
New biodegradable poly(ether-urethane)s (PEU)s were synthesized via the reaction of L-leucine anhydride cyclo-peptide, polyethylene glycol-1000 and hexamethylene diisocyanate. Then, they were end-functionalized with aspartic acid (AS) as a dispersing agent and were dispersed in water. MWCNTs were also functionalized by AS under microwave irradiation. Polymer/MWCNT-AS composites and polymer/MWCNT-AS water dispersed composites were prepared through an ultrasound-assisted method. We have designed these PEUs with two different structural architectures (PA1and PA2) which can be readily dispersed in water (PA1-D and PA2-D). The structure and properties of the polymers, MWCNTs-AS and PEUs/MWCNTs-AS composites were investigated by FTIR and NMR spectroscopy methods and FE-SEM, TEM and TGA techniques. The particle sizes of the resulting PA1-D and PA2-D dispersions were in the range of 200–300 nm. The results showed that by increasing MWCNT-AS loading, the degradation rate and particle sizes of the dispersed composites decreased, while thermal stability and dispersion stability of the composite systems increased. The degradation tests of polymers and their composites in PBS at 37 °C after 10 days showed weight losses ranging from 23 to 44 and 17–37%, respectively. The cytotoxicity study of polymers using the direct-contact test on L929 mouse fibroblast cell line showed no toxicity. Other properties such as thermal stability, dispersion’s particle size, degradation rate and morphology of the composites were studied, and the effect of simultaneous dispersion of MWCNTs-AS and PEUs in water on the properties of the resulting mixtures was studied. We suggest that these polymers have tunable properties which may potentially be considered for drug carriers’ studies. © 2018, Iran Polymer and Petrochemical Institute.
Designed Monomers and Polymers (1385772X) (4)
In this study, the effect of organically modified montmorillonite (OMMT) on the properties of water-based polyurethane (WPU) colored coatings was studied. For this, a dye incorporated waterborne polyurethane anionomer (WPUA) containing 3 mol% of 2,2-Bis(hydroxymethyl) propionic acid (DMPA) as a matrix polymer was synthesized. Cloisite30B/WPUA nanocomposites containing various amounts of OMMT were prepared by the insitu method. The structural, morphological, and thermal characteristics of Cloisite30B/WPUA nanocomposites were performed by WAXS, transmission electron microscopy (TEM), scanning electron microscopy (SEM), FT-IR spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). From the WAXS and TEM analyses, it was found that the OMMT layers were completely exfoliated and dispersed in the PUA matrix. The influence of different OMMT loading on the properties of the nanocomposite was also investigated. OMMT/WPUA nanocomposites exhibited enhanced thermal and scratch resistance relative to the pure WPUA. The DSC results indicated an increase in Tg and melting temperature of the OMMT/WPUA nanocomposites compared to pure WPUA. © 2015 Taylor and Francis.
Journal of Applied Polymer Science (00218995) (39)
In this study, plasticized poly(vinyl chloride) (PVC) composites with different nanofillers, including single-walled carbon nanotubes (SWCNTs), organoclay, TiO2, and ZnO nanoparticles, were prepared, and their effects on plasticizer migration were investigated. Scanning electron micrographs revealed the dispersion quality of the nanofillers in the polymer matrix. It had a significant influence on the performance of the nanofillers in the process of plasticizer migration. Migration and exudation tests showed that the nanofillers could efficiently hinder plasticizer migration. On the basis of these results, we concluded that carbon nanotubes were the best antimigration agent in the plasticized system. This was ascribed to the high aspect ratio of the SWCNTs and the good interactions between them and the plasticizer. Also, TiO2 nanoparticles showed a better performance compared to the ZnO nanoparticles. This was due to the more homogeneous dispersion of the TiO2 in the polymer matrix and the higher surface area of the particles. The differential scanning calorimetry thermograms were in good agreement with the migration tests. The lowest change in the glass-transition temperature was observed for the composite filled with SWCNTs. This indicated that a lower amount of the plasticizer migrated from PVC. The thermogravimetric analysis curves showed that the incorporation of the nanofillers improved the thermal stability of the PVC. The results could be useful for determining the efficiency of plasticized PVC in applications. © 2015 Wiley Periodicals, Inc.
Applied Biochemistry and Biotechnology (02732289) (4)
The present work for the first time investigates the effect of Bacillus amyloliquefaciens, M3, on a new poly(ether-urethane-urea) (PEUU). PEUU was synthesized via reaction of 4,4′-methylenebis(4-phenylisocyanate) (MDI), l-leucine anhydride cyclopeptide (LACP) as a degradable monomer and polyethylene glycol with molecular weight of 1000 (PEG-1000). Biodegradation of the synthesized PEUU as the only source for carbon and nitrogen for M3 was studied. The co-metabolism biodegradation of the polymer by this organism was also investigated by adding mannitol or nutrient broth to the basic media. Biodegradation of the synthesized polymer was followed by SEM, FT-IR, TGA, and XRD techniques. It was shown that incubation of PEUU with M3 resulted in a 30–44 % reduction in polymer’s weight after 1 month. This study indicates that the chemical structure of PEUU significantly changes after exposure to M3 due to hydrolytic and enzymatic degradation of polymer chains. The results of this work supports the idea that this poly(ether-urethane) is used as a sole carbon source by M3 and this bacterium has a good capability for degradation of poly(ether-urethane)s. © 2015, Springer Science+Business Media New York.
Journal of Applied Polymer Science (10974628) (4)
A new series of poly(amide-imide)s (PAI) modified with a siloxane linkage was synthesized under microwave radiation in ionic liquids and organic salts via the isocyanate method. The polymerization reactions of a novel siloxanic diacid monomer with 4,4'-methylene-bis(4-phenylisocyanate) MDI were studied in ammonium, phosphonium, and imidazolium-type organic salts. These poly(amide-imide-siloxane)s (PAI-Si)s were obtained with high yields and good inherent viscosities ranging from 0.30 to 0.55 dL/g. The normally high softening temperatures and poor solubility of PAIs in organic solvents were improved via the incorporation of the flexible siloxane segments into the polymer backbone. The PAI-Sis showed glass transition temperatures around 100°C and their 10% mass loss was about 300°C. They have a char yield in the range of 30-40% at 800°C. Calculated limiting oxygen index values of the polymers were about 30; therefore, they can be considered as self-extinguishing. The dielectric constants of these silane-containing PAIs (2.5) are lower than common siloxane-free polyimides (∼ 3). Their good thermal stability, enhanced solubility, and low dielectric constants suggest they may function as electrical insulators. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 Copyright © 2012 Wiley Periodicals, Inc.
Amino Acids (14382199) (2)
Conventional polyurethanes (PUs) are among biomaterials not intended to degrade but are susceptible to hydrolytic, oxidative and enzymatic degradation in vivo. Biodegradable PUs are typically prepared from polyester polyols, aliphatic diisocyanates and chain extenders. In this work we have developed a degradable monomer based on α-amino acid to accelerate hard segment degradation. Thus a new class of degradable poly(ether-urethane-urea)s (PEUUs) was synthesized via direct reaction of 4,4′-methylene-bis(4- phenylisocyanate) (MDI), l-leucine anhydride (LA) and polyethylene glycol with molecular weight of 1,000 (PEG-1000) as polyether soft segment. The resulting polymers are environmentally biodegradable and thermally stable. Decomposition temperatures for 5 % weight loss occurred above 300 C by TGA in nitrogen atmospheres. Some structural characterization and physical properties of these polymers before and after degradation in soil, river water and sludge are reported. The environmental degradation of the polymer films was investigated by SEM, FTIR, TGA, DSC, GPC and XRD techniques. A significant rate of degradation occurred in PEUU samples under river water and sludge condition. The polymeric films were not toxic to E. coli (Gram negative), Staphylococcus aureus and Micrococcus (Gram positive) bacteria and showed good biofilm formation on polymer surface. Our results show that hard segment degraded selectively as much as soft segment and these polymers are susceptible to degradation in soil and water. Thus our study shows that new environment-friendly polyurethane, which can degrade in soil, river water and sludge, is synthesized. © 2012 Springer-Verlag.
Journal of Research in Medical Sciences (17357136) (11)
Introduction: This study is performed to investigate the effect of strength and endurance training on the levels of depression, anxiety, and C-reactive proteins inflammatory biomarker changes. Materials and Methods: The research method was experimental, and the statistical population is formed of 300 volunteer male students. After the pre-test, 120 subjects with notable depression and anxiety levels obtained from Beacke and Ketel's questionnaires were selected and randomly divided into two groups of strength and endurance, each containing 60 subjects, and then, again into two groups of experimental and control, each with 30 subjects. All 120 subjects were blood-sampled in the first stage to determine CRP concentration. After 20 sessions of strength and endurance exercises again depression, anxiety, and C-reactive proteins testes were used for both control and experimental groups. Ultimately, the obtained data were analyzed by using t-test in dependent and independent groups and covariance analysis in P 0.05 level. Results: The results showed that the average of age is 25.1±3.2, average of weight is 70.4±8.4 and average of height is 169.8±12.1, in the subjects. Also, the strength and endurance training had reduced the anxiety by 27% (P =.0001), depression by 37% (P =.0001) and C-reactive proteins by 20% (P =.0001), in the subjects. Discussion: Regarding the different effects of training types on research variables, the results showed that the endurance training has a greater effect in reducing the depression, and strength training, in blood C-reactive proteins reduction, Although, no significant difference was observed between anxiety-reducing effects of strength and endurance training.
Rafiemanzelat, F. ,
Abdollahi, E. ,
Moghadam, M. ,
Mirkhani, V. ,
Tangestaninejad, S. ,
Mohammadpoor baltork, I. Journal of Applied Polymer Science (00218995) 124(1)pp. 638-646
New electron deficient tin(IV) porphyrins were used as efficient catalysts for the reaction of 4,4â-methylene-bis-(4-phenylisocyanate) (MDI), with L-leucine anhydride cyclodipeptide (LAC) and polyethyleneglycol-400 (PEG-400) and the results were compared with those obtained in the presence of a commercial catalyst, dibutyltin dilaurate (DBTDL). Molar ratio of catalysts to MDI, polymerization reaction time, viscosity, and yield of the resulting poly(ether-urethane-urea)s (PEUU) were compared in the presence of different catalysts. The rate of NïCïO conversion in the presence of each catalysts under the same reaction conditions was also compared and followed by FT-IR NïCïO absorption band. FT-IR, GPC, and viscosity studies have shown that tin(IV) porphyrins afford higher viscosity and reaction progress. © 2011 Wiley Periodicals, Inc.
Macromolecular Research (20927673) (9)
In this study novel multi block polyurethane (PU) copolymers containing cyclodipeptide were synthesized under microwave irradiation using a quaternary ammonium salt (QAS) as reaction media. For this, L-leucine cyclodipeptide (LC) was prepared and then a new class of poly(ether-urethane-urea)s (PEUUs) was synthesized in tetrabutylammonium bromide (TBAB) via two-step polymerization method. In the first step, 4,4'-methylene-bis-(4-phenylisocyanate) (MDI) was reacted with LC to produce isocyanate-terminated oligo(imide-urea) as hard segment. The reaction of the aforementioned pre-polymer with poly(ethylene glycols) (PEG) with different molecular weights (PEG400, 600, 1000, and 2000) was the second step to furnish a series of new PEUUs. These PEUUs are thermally stable, soluble in amide-type solvents, hydrolysable, and biodegradable. The resulting PEUUs have inherent viscosities in the range of 0.37-0.67 dL/g. The effects of polymerization method and soft segment length on some of the polymers' properties and their structural characteristics were compared. The protocol presented here has the merits of environmentally benign, simple operation, convenient work-up, short reaction time and good yields without using volatile organic solvents or catalysts. Ammonium type reaction medium was air and water stable, and relatively cheap, which makes it suitable for applications. The results demonstrate that it can be easily separated and reused without losing activity which makes the method cost effective and eco-benign.
Amino Acids (14382199) (6)
This study concerns the synthesis of novel multi block polyurethane (PU) copolymers containing cyclodipeptide, taking the advantage of ionic liquids (ILs) under microwave irradiation. For this, l-leucine anhydride cyclodipeptide (LACP) was prepared and then a new class of poly(ether-urethane-urea)s (PEUUs) was synthesized in molten ammonium type ILs. ILs were used as reaction media and PUs were prepared via two-step polymerization method. In the first step, 4,4′-methylene-bis-(4-phenylisocyanate) (MDI) was reacted with LACP to produce isocyanate-terminated oligo(imide-urea) as hard segment (NCO-OIU). Chain extension of the aforementioned pre-polymer with polyethyleneglycol (PEG) of molecular weights of 1000 (PEG-1000) was the second step to furnish a series of new PEUUs. These multiblock copolymers are thermally stable, soluble in amide-type solvents, hydrolysable and biodegradable. PEUUs prepared in ILs under microwave irradiation showed more phase separation and crystallinity than PEUUs prepared under conventional method. The protocol presented here has the merits of environmentally benign, simple operation, convenient work-up, short reaction time and good yields without using volatile organic solvents, and catalysts. Ammonium type reaction media were air and water stable, and relatively cheap, which makes them suitable for application. The results demonstrate that they can be easily separated into water and reused without losing activity. Reusability of tetrabutylammonium bromide as reaction media makes the method a cost effective and environmentally benign method under microwave irradiation. Thus, we could prepare environmentally friendly polymers via environmentally benign method. © 2011 Springer-Verlag.
Polymer Degradation and Stability (01413910) (1)
3,6-diisobutyl-2,5-diketopiperazine (DIBDKP) was prepared from L-Leucine with good yield. Then a new class of biodegradable poly(ether-urethane)s (PEUs) was synthesized by the pre-polymerization reaction of DIBDKP with 4,4-methylene-bis-(4-phenylisocyanate) (MDI). Prepolymer reacted with poly(tetramethylene glycol) (PTMG) with molecular weight of 1000 (PTMG-1000) to obtain a series of new poly(ether-urethane-urea)s (PEUU)s. These multiblock copolymers are biodegradable and thermally stable. Some structural characterization and physical properties of these polymers before and after degradation in soil, river water and sludge are reported. The environmental degradation of the polymer films was investigated by SEM, FT-IR, TGA, DSC, GPC and XRD techniques. A significant rate of degradation was occurred in PEU samples under river water and sludge condition. The polymeric films were not toxic to Escherichia coli (Gram negative), Staphylococcus aureus and Micrococcus (Gram positive) bacteria and showed good biofilm formation on polymer surface. Our results show that hard segment degraded selectively as much as soft segment and these polymers are susceptible to degradation in soil and water. © 2011 Elsevier Ltd. All rights reserved.
Polymer Bulletin (01700839) (4)
In this work, some segmented poly(ether-urethane-urea)s (PEUUs) containing aza crown ether (cryptand) were prepared and characterized. These polymers were synthesized via the reaction of kryptofix 22 with 2 mol excess of 4,4′-methylene-bis-(4-phenylisocyanate) (MDI), and different molecular weights of polyethylene glycols (PEGs). Morphology, thermal, and complexation properties of these polymers were studied by Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), atomic absorption spectroscopy (AAS), and solid state NMR (S-NMR). The data confirmed complexation ability of these polymers for Li+ ion absorption and revealed the effect of Li+ ion complexation on the morphology and thermal behavior of the PEUUs. © 2010 Springer-Verlag.
Polymer Degradation and Stability (01413910) (6)
l-leucine anhydride cyclodipeptide (LAC) was prepared through a green method under microwave irradiation with good yield. Then a new class of hydrolysable poly(ether-urethane-urea)s (PEUUs) was synthesized via two-step polymerization method. In the first step, 4,4′-methylene-bis-(4-phenylisocyanate) (MDI) was reacted with LAC to produce isocyanate-terminated poly(imide-urea) oligomers (hard segment). Reaction of the resulting pre-polymer with different molecular weights (MW) of polyethyleneglycols (PEG)s such as PEG-400, PEG-600, PEG-1000 and PEG-2000 was the second step to furnish a series of new PEUUs. The resulting multiblock copolymers have inherent viscosities in the range of 0.4-1.8 dL/g. These multiblock copolymers are hydrolysable, thermally stable and soluble in amide-type solvents. Polymers containing different molecular weights of PEGs soft segments show different thermal stability, phase separation, hard segment cohesiveness and hydrolysis rate. Some structural characterization and physical properties of these PEUUs are reported. © 2010 Elsevier Ltd. All rights reserved.
Journal of Applied Polymer Science (10974628) (5)
A new class of optically active poly(amide imide urethane)s (PAIUs) was synthesized via a two-step diisocyanate route. In the first step, 4,4′-methylenebis(phenyl isocyanate) (MDI) was reacted with different diacids to produce an isocyanate-terminated oligo(amide imide). The chain extension of the previous hard segment with poly (ethylene glycol) diols with a molecular weight of 400 was the second step for furnishing a series of new PAIUs. N-Trimellitylimido-L-leucine was used as a diacid monomer for polycondensation reactions. Polymerization reactions were performed without any catalysts or with pyridine or dibutyltin dilaurate as a catalyst. The optimized reaction conditions were used for the reaction of N-trimellitylimido-L- isoleucine, N-trimellitylimido-L-methionine, N-trimellitylimido-s-valine, and N-trimellitylimido-L-phenylalamne as diacid monomers with MDI. The resulting multiblock copolymers had inherent viscosities of 0.25-0.78 dL/g. These multiblock copolymers were optically active, thermally stable, and soluble in amide-type solvents. All these polymers were fully characterized with Fourier transform infrared spectroscopy,1H-NMR and ultraviolet-visible spectroscopy, specific rotation measurements, and thermal analyses. Some structural characteristics and physical properties of these new optically active PAIUs were examined. © 2008 Wiley Periodicals, Inc.
High Performance Polymers (13616412) (2)
Two series of thermally modified thermoplastic polyurethane elastomers (TPU)s based on poly(oxytetramethylene glycol) (PTMG) (PT samples), and poly(oxyethylene glycol) (POE) (PO samples) were synthesized from 4,4'-methylene-bis-(4-phenylisocyanate) (MDI) and an aromatic diacid, bis(p-amido benzoic acid)-N-trimellitylimido- L-leucine (BPABTL) (1). The aromatic diacid contains a L-leucine group and a preformed imide ring. The novel diacid was reacted with excess MDI to give an isocyanate terminated oligomer that was subsequently reacted with a polyol to give the poly(amide-imide-ether- urethane)s (PAIEU)s. The properties of the resulting PAIEUs were compared with poly(ether urethane)s without incorporation of BPABTL. The PAIEUs had a constant soft segment (SS) length derived from the polyol (average Mn 1000) but a variable hard block length. Studies were conducted on the effect of hard segment (HS) molar ratio on dynamic mechanical thermal properties, thermal properties, phase separation, crystallinity and solvent resistance of these new PAIEUs. © 2008 SAGE Publications.
Iranian Polymer Journal (10261265) (1)
For the first time, we report the optimization of reaction conditions for the synthesis of novel thermally modified optically active poly(amide-imide- ether-urethane)s (PAIEU)s prepared by diisocyanate route. The effects and importance of different reaction parameters such as reaction temperature, reaction time, and soft segment length on the controlling of chain growth of the resulting copolymers were investigated. Thus, four different series of PAIEUs based on different molecular weight of polyethylene glycol (PEG)s were synthesized through the reaction of a new imide containing diacid, with 4,4′-methylene-bis-(4-phenylisocyanate) (MDI). A linear correlation was constructed using experimental values of viscosities of the resulting copolymers based different molecular weights of PEGs at different reaction temperatures, and reaction time. The influence of each parameter was studied by factorial design analysis. Analysis of variance (ANOVA) was also used to evaluate the significance of the linear regression model (correlation). The statistical parameters reveal strong evidence that the constructed correlation is reliable.
Polymer Bulletin (01700839) (2)
Two series of new optically active poly(amide-imide-ether-urethane)s (PAIEU)s based on polytetrahydrofuran (PTHF), of Mn=1000 as soft segment were synthesized. These copolymers were prepared via direct polycondensation reaction of an aromatic diacid based on L-leucine with preformed imide ring, 4,4'-methylene-bis-(4-phenylisocyanate) (MDI) and PTHF-1000. The effects of different reaction conditions and method of preparation (one-step vs. two-step method) on the physical properties of these new PAIEUs have been investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide angle X-ray scattering (WAXS), FTIR spectroscopy, and dynamic mechanical thermal analysis (DMTA). The effect of the introduction of bis(p-amido benzoic acid)-N-trimellitylimido-L-leucine (BPABTL) (1) into PU back-bone on their properties was also studied. © Springer-Verlag 2007.
Dyes and Pigments (01437208) (3)
In this work, four series of new self-colored segmented polymeric dyes were successfully synthesized via the reaction of an azo-based diacid, different diisosyanates and polyethylene glycol with molecular mass of 400 (PEG-400), under microwave irradiation via diisocyanate route. The polymers were characterized using FT-IR, 1H NMR, UV-vis spectroscopy and flourimetery. The inherent viscosities of the poly(amide-ether-urethane)s (PAEU)s were in the range of 0.28-0.75 dL/g. Thermal properties of the PAEUs were evaluated by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). In terms of dye migration character, the PAEUs with a covalent molecule of dye are proven to have much lower thermal migration values (Mp%) than those of simple mixing of polymer and dyestuff. Solvent resistance and solvent migration of resulting colored copolymers were also compared with monomeric dye in different solvents. The resulting copolymers showed good viscosities, solvent and thermal migration resistance and good thermal stability. © 2006 Elsevier Ltd. All rights reserved.
Polymer Bulletin (01700839) (1)
Three series of new optically active poly(amide-imide-ether-urethane) (PAIEU) copolymers with different soft segments including polyethylene glycol (PEG), polypropylene glycol (PPG) or polytetramethylene glycol (PTMG) of molecular weight (MW) of 1000 were successfully synthesized. These copolymers were prepared via direct polycondensation reaction of an aromatic diacid based on L-leucine (1), 4,4'-methylene-bis-(4-phenylisocyanate) (MDI) (2) and different polyether polyols. FTIR spectroscopy shows the different absorption bands of NH, urethane and imide-I, II groups that suggests the different intermolecular interactions due to hydrogen bonding in these PAIEUs. On the other hand, DSC analysis reveals that the glass transition temperature for hard segments (Tgh) of PAIEUs based on polyethers with higher ratio of O/CH 2 is higher than that of polyethers with lower ratio of O/CH 2 and it decreases with the soft segment length in PAIEUs consisting of the same type of PEG soft segments.
Iranian Polymer Journal (10261265) (1)
In connection with our interest in preparing thermally stable optically active polymers, this work deals with a detailed study on the synthesis and characterization of three series of novel optically active poly(ether-urethane)s (PEU)s based on polytetrahydrofuran (PTHF), polyoxyethylene (POE) and polypropyleneglycole (PPG). Also the possibility of their thermal modification by introducing the imide and amide functions in the PEU backbone through the reaction of a new imide containing diacid, bis(p-amido benzoic acid)-N-trimellitylimido-L-leucine (BPABTIL) (1) with 4,4′-methylene-bis- (4-phenylisocyanate) (MDI) (2) was explored. The effect of different reaction conditions such as reaction temperature, reaction time, catalysts, reaction solvent, soft segment length and type, method of preparation and addition of chain extender on the properties of copolymers including solubility, viscosity and thermal behaviours were investigated.
European Polymer Journal (00143057) (12)
A new class of optically active poly(amide-imide)s based on an α-amino acid was synthesized via direct polycondensation reaction of different diisocyanates with a chiral diacid monomer. The step-growth polymerization reactions of N-trimellitylimido-S-valine (TISV) (1) with 4,4′-methylene-bis(4-phenylisocyanate) (MDI) (2) was performed under microwave irradiation, as well as solution polymerization under graduate heating and reflux conditions. The optimized polymerization conditions for each method were performed with tolylene-2,4-diisocyanate (TDI) (3), hexamethylene diisocyanate (HDI) (4), and isophorone diisocyanate (IPDI) (5) to produce optically active poly(amide-imide)s via diisocyanate route. The resulting polymers have inherent viscosities in the range of 0.02-1.10 dL/g. Decomposition temperatures for 5% weight loss (T5) occurred above 300 °C (by TGA) in nitrogen atmospheres. These polymers are optically active, thermally stable and soluble in amide-type solvents. Some structural characterization and physical properties of this new optically active poly(amide-imide)s are reported. © 2005 Elsevier Ltd. All rights reserved.
Iranian Polymer Journal (10261265) (10)
Anew class of optically active poly(amide-imide-urethane)s (PAIUs) was synthesized via one-step diisocyanate route under microwave irradiation. 4,4′;-methylenebis-(4-phenylisocyanate) (MDI) was reacted with bis(p-amido benzoic acid)-N-trimellitylimido-L-leucine (BPABTL) and polyethyleneglycol- diols (PEG)s to furnish a series of new PAIUs. The effect of different reaction conditions such as irradiation power, irradiation time, reaction solvent, soft segment length, and reaction catalysts as well as no catalyst condition were investigated. Also, the possibility of the synthesis of modified thermoplastic polyether urethanes by introducing the imide and amide functions in the Polyurethane (PU) backbone was explored. The resulting multiblock copolymers have inherent viscosities in the range of 0.09-0.63 dL/g. These copolymers are optically active, thermally stable and soluble in amide-type solvents.
Journal of Applied Polymer Science (00218995) (4)
A new class of optically active poly(amide-imide-urethane)s (PAIUs) was synthesized via a two-step diisocyanate route under microwave irradiation. In these reactions, 4,4′-methylene-bis(4-phenylisocyanate) was reacted with bis(p-amido benzoic acid)-N-trimellitylimido-L-leucine and poly(ethylene glycol diol)s (PEGs), such as PEG-400, PEG-600, PEG-1000, and PEG-2000, to furnish a series of new PAIUs. The effects of different reaction conditions, such as the method of preparation (polyol or acid chain extension), the prepolymerization step (NCO-terminated oligoamide or NCO-terminated polyether polyol), the irradiation time and power, the reaction solvent, the soft-segment length, and the presence or absence of reaction catalysts (e.g., triethylamine, pyridine, and dibutyltin dilaurate), on the properties of the copolymers, including the solubility, viscosity, and thermal behavior, were investigated. The resulting multiblock copolymers had inherent viscosities of 0.15-0.53 dL/g. These multiblock copolymers were optically active, thermally stable, and soluble in amide-type solvents. © 2005 Wiley Periodicals, Inc.
Reactive and Functional Polymers (13815148) (2)
A new class of optically active poly(amide-imide-urethane)s (PAIUs) was synthesized via two-step diisocyanate route. In the first step, 4,4′-methylene-bis-(4-phenylisocyanate) (MDI) was reacted with bis(p-amido benzoic acid)-N-trimellitylimido-l-leucine (BPABTL) to produce the diisocyanate-terminated polyamide oligomers (hard segment). The chain extension of the above hard segment with the polyethyleneglycol-diols (PEGs) such as PEG-400, PEG-600, PEG-1000 and PEG-2000 was the second step to furnish a series of new PAIUs. Polycondensations were performed in the presence of triethylamine (TEA), pyridine (Py), dibutyltin dilurate (DBTDL) as a catalyst and without catalyst, respectively, in different solvents, different reaction time and reaction temperatures. The resulting multiblock copolymers have inherent viscosities in the range of 0.08-0.82 dL/g. These multiblock copolymers are optically active, thermally stable and soluble in amide-type solvents. All of the above polymers were fully characterized by IR spectroscopy, 1H NMR spectroscopy, elemental analyses, specific rotation and thermal analyses. Some structural characterization and physical properties of these new optically active PAIU thermoplastic elastomers are reported. © 2004 Elsevier B.V. All rights reserved.
Iranian Polymer Journal (10261265) (2)
A new class of optically active poly(amide imide urethane) (PAIU) thermoplastic elastomers was synthesized via the reaction of NCO-terminated polyether polyols with an imide containing optically active amino acid-based dicarboxylic acid chain extender via two-step diisocyanate route. In the first step 4,4′-methylene-bis-(4-phenylisocyanate) (MDI) (6) was reacted with polyethyleneglycol-diols (PEG)s such as PEG-400, PEG-600, PEG-1000, and PEG-2000 to produce the NCO-terminated polyether soft segment. The chain extension of the above soft segment with bis(p-amido benzoic acid)-N-trimellitylimido-L- leucine (BPABTL) (5) was the second step to furnish a series of new optically active PAIUs. The PAIUs were characterized by conventional methods, and their physical properties such as solution viscosity, solubility, and thermal behaviour were studied. The copolymerization reactions were performed in the presence of triethylamine (TEA), pyridine (Py), dibutyltin dilurate (DBTDL), and no catalyst, respectively. The resulting multiblock copolymers had inherent viscosities in the range of 0.12-0.55 dL/g. These copolymers are optically active, thermally stable and soluble in amide-type solvents. Some structural characterization and physical properties of these new optically active PAIU thermoplastic elastomers are reported.
Journal of Applied Polymer Science (00218995) (4)
A new class of optically active poly(amide imide)s were synthesized via direct polycondensation reaction of diisocyanates with a chiral diacid monomer. The step-growth polymerization reactions of monomer bis(p-amido benzoic acid)-N-trimellitylimido-L-leucine (BPABTL) (5) as a diacid monomer with 4,4′-methylene bis(4-phenylisocyanate) (MDI) (6) was performed under microwave irradiation, solution polymerization under gradual heating and reflux condition in the presence of pyridine (Py), dibuthyltin dilurate (DBTDL), and triethylamine (TEA) as a catalyst and without a catalyst, respectively. The optimized polymerization conditions according to solvent and catalyst for each method were performed with tolylene-2,4-diisocyanate (TDI) (7), hexamethylene diisocyanate (HDI) (8), and isophorone diisocyanate (IPDI) (9) to produce optically active poly (amide imide)s by the diisocyanate route. The resulting polymers have inherent viscosities in the range of 0.09-1.10 dL/g. These polymers are optically active, thermally stable, and soluble in amide type solvents. All of the above polymers were fully characterized by IR spectroscopy, 1H NMR spectroscopy, elemental analyses, specific rotation, and thermal analyses methods. Some structural characterization and physical properties of this new optically active poly(amide imide)s are reported. © 2004 Wiley Periodicals, Inc.
Polymer International (09598103) (2)
Cis-9,10-dihydro-9,10-ethanoanthracene-11-12-dicarboxylic acid anhydride (1) was converted into its amic acid derivative by reaction with L-leucine. The cyclization reaction was carried out in situ using triethylamine to give the succinic imide-acid derivative (2). Compound (2) was converted to the acid chloride (3) by reaction with thionyl chloride. The reaction of acid chloride (3) with isoeugenol (4) was carried out in chloroform and a novel optically active isoeugenol ester derivative (5) was obtained in high yield. 4-Phenyl-1,2,4-triazoline-3,5-dione (PhTD) (6) was allowed to react with compound (5). The reaction is very fast and gives only one diastereoisomer of (7) via Diels-Alder and ene pathways in quantitative yield. Compound (7) was characterized by 1H NMR, IR, specific rotation and elemental analysis, and was used as a model for the polymerization reactions. The polymerization reactions of compound (5) with bis-triazolinediones (8), (9) were performed in N,N-dimethylacetamide (DMAc) at room temperature. The reactions are exothermic and fast, and give novel optically active polymers. Some physical properties and structural characterizations of these new polymers have been studied, and are reported. © 1999 Society of Chemical Industry.
Vysokomolekularnye Soedineniya. Ser.A Ser.B Ser.C - Kratkie Soobshcheniya (05075475) (8)
New polyurethanes bearing benzo[k]fluoranthene moieties in the main chain were synthesized by the reaction of 7,12-bis(2-hydroxyethyl)benzo[k]fluoranthate with hexamethylene-, isophorone, or tolylene 2,4-diisocyanates. The reaction was carried out without a catalyst in the presence of triethylamine or pyridine; chloroform or the mixtures of DMAA with chloroform or dioxane were used as solvents. The resulting polyurethanes exhibit high fluorescent activity and can be used as photoactive tracers.
Iranian Polymer Journal (10261265) (1)
7,12-Bis(2-hydroxyethyl)benzo[k]fluoranthate (BHBF) was prepared from benzyne intermediate in four steps. Polycondensation of BHBF with isophthaloyl dichloride and terephthaloyl dichloride was performed by solution as well as interfacial techniques. The solution polymerizations were performed in chloroform and in DMAc (N,N′-dimethylacetamide)/chloroform system, in the presence of pyridine or triethylamine at room or refluxing temperature. The interfacial polymerizations were performed by DMAc/cyclohexane, an organic/ organic system, in the presence of pyridine or triethylamine at room temperature. The above polymerization reactions lead to the formation of novel aromatic polyesters having benzo[k]fluoranthene moieties in the main chain. The resulted polyesters show intense violet fluorescence property and were characterized by IR, 1H NMR, UV, DSC and the elemental analyses. The fluorescence excitation and emission spectra of the monomer BHBF and one of the polyesters (PS2) were also studied. Some physical properties of these novel polymers are also reported.
Iranian Polymer Journal (10261265) (4)
Polybutadiene with a narrow molecular weight is synthesized by anionic polymerization of butadiene monomer in cyclohexane at 20 °C using n-butyllithium as initiator. This polymer is statistically functionalized with 4-phenyl-1,2,4-triazoline-3,5-dione by hydrogen abstraction addition reaction (ene reaction) in an extent of 5, 10, and 15%. These functionalized polymers are reacted with acetyl chloride as well as benzoyl chloride in presence of pyridine at room temperature. These reactions lead to the replacement of N-H with acetyl and benzoyl groups. The amount of urazole and acyl incorporation are determined by 1H NMR technique. Some physical properties of these modified polybutadienes are reported.
Electrically conductive epoxy thermosets are getting widespread consideration due to the fast-growing advanced engineering material industry. There are known platforms for encapsulating semiconductors, equipment constituents, electric circuit board substances, aerospace, etc. Currently, various efforts are being made to manufacture conductive epoxy-based nanocomposites, and a systematic and comprehensive understanding is required to move the achievements a step ahead. The conduction mechanism appears as a result of conductive network formation created in the presence of a specific type of additives, namely electrically conductive fillers. Conductive fillers are powders, fibers, and other materials added to epoxy resin to make it easier for electrons to pass through. This chapter describes how the electrical conductance of epoxy thermosets is improved using different types of conductive fillers. The emphasis is on conventional electrically conductive agents (e.g., metals, carbonaceous fillers, and intrinsically conductive polymers) as well as green ionic mixtures, including multi-functioning ionic liquids and deep eutectic solvents. The latter category is important since ionic mixtures can play simultaneously as epoxy hardening compounds and curing catalysts, in addition to their role as electrically conductive agents. Numerous examples of recent and current research activities are given to introduce a complete background of achievement. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Biodegradable and biocompatible polyurethanes are a class of polymers that are useful in medical industry. In this study, new biodegradable and nontoxic water dispersed co-poly(ether-urethane-urea)s (PEUU)s were synthesized based on amino acid and peptide moiety. These polymers were prepared via the reaction of L-leucine anhydride cyclopeptid (LAC), polyethylene glycol (PEG), hexamethylene diisocyante (HDI) and serine (S) as dispersing agent. These polymers were characterized by FT-IR, NMR, TGA, DSC, AFM, and DLS. PEUU polymers were synthetized with three different structural architectures and block sequence. The polymer’s particle size dispersions are around 300 nm. The degradation test was carried out in PBS at 37 °C and evaluated by weight loss, viscosity and particle size decrement as well as by AFM. In order to determine cytotoxicity of the polymers, in vitro toxicity of final polymer was assessed using L929 mouse fibroblast cell line. The results showed no cytotoxicity of these polymers. © Springer Nature Switzerland AG 2020.
