Synthesis, Characterization and Properties of Some Main-Chain Ferrocene-Based Polymers Containing Aromatic Units (original) (raw)
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Polymer, 2002
Three kinds of polyfunctional polyols with hydroxyl values of 180-320 mg/g were prepared by the reaction of hydrogenated terpinene-maleic ester type epoxy resin with secondary amines (diethylamine, N-methylethanolamine, and diethanolamine), and the chemical structures were characterized by Fourier transform infrared spectroscopy and NMR spectroscopy. These polyols were used in place of commonly used polyols to prepare twocomponent polyurethanes when reacted with polyisocyanates. The crosslinking reactions of the polyols with polyisocyanate could be catalyzed by the tertiary amine groups included in the polyols, and the reaction rate was affected by hydrochloric acid and the polarity of the solvents. The mechanical, water-resistance, and chemical-resistance properties of the crosslinked products of the polyols were evaluated by standard tests, and the thermal properties were examined by differential scanning calorimetry and thermogravimetric analysis. The results show that these epoxyurethane polymers, with glass-transition temperatures (T g 's) in the range À5 to 37 C, had good thermally resistant properties, and the temperatures at 5% weight loss were in the range 235-280 C. All of the polymers formed transparent, strong, flexible films, with good chemical-resistance properties and excellent impact strengths of greater than 50 cm, a flexibility of 0.5 mm, adhesions of 1-2, and pencil hardnesses of HB-2H. The larger OH functionality and OH value of the polyol resulted in higher T g and pencil hardness values and better alcohol resistance and thermal stability in the crosslinked product of the polyol. V
Polymer Composites, 2022
Three kinds of polyfunctional polyols with hydroxyl values of 180-320 mg/g were prepared by the reaction of hydrogenated terpinene-maleic ester type epoxy resin with secondary amines (diethylamine, N-methylethanolamine, and diethanolamine), and the chemical structures were characterized by Fourier transform infrared spectroscopy and NMR spectroscopy. These polyols were used in place of commonly used polyols to prepare twocomponent polyurethanes when reacted with polyisocyanates. The crosslinking reactions of the polyols with polyisocyanate could be catalyzed by the tertiary amine groups included in the polyols, and the reaction rate was affected by hydrochloric acid and the polarity of the solvents. The mechanical, water-resistance, and chemical-resistance properties of the crosslinked products of the polyols were evaluated by standard tests, and the thermal properties were examined by differential scanning calorimetry and thermogravimetric analysis. The results show that these epoxyurethane polymers, with glass-transition temperatures (T g 's) in the range À5 to 37 C, had good thermally resistant properties, and the temperatures at 5% weight loss were in the range 235-280 C. All of the polymers formed transparent, strong, flexible films, with good chemical-resistance properties and excellent impact strengths of greater than 50 cm, a flexibility of 0.5 mm, adhesions of 1-2, and pencil hardnesses of HB-2H. The larger OH functionality and OH value of the polyol resulted in higher T g and pencil hardness values and better alcohol resistance and thermal stability in the crosslinked product of the polyol. V
Newly Developed Epoxy-Polyol and Epoxy-Polyurethane From Renewable Resources
British Journal of Applied Science & Technology, 2013
Bio-polyols are important component in polyurethane industries. The preliminary studies into the synthesis of bio-polyol products (epoxy-polyol and epoxyl-polyurethanes) from Jatropha curcas were investigated. The reactions were followed by both Infrared and nuclear magnetic resonance. Infrared analysis was performed on a Nicolet 380 Fouriertransform infrared (FTIR) spectrophotometer using NaCl cells.
Polymer, 2010
A synthetic two-stage procedure was developed for the synthesis of moderately crosslinked polymers based on poly(aryl-ethereethereketone) (PEEK). Rigid crosslinks based on aromatic imines were synthetically introduced into PEEK polymer matrix resulting in PEEK materials with various degrees of crosslinking. Two specific crosslinked PEEK polymers (5% and 10% of ketone groups crosslinked) were characterized and studied in detail. Thermomechanical properties, as well as chemical/solvent resistance of these materials at high temperatures (175e280 C) were investigated and compared to the original PEEK material (Victrex 151G). The introduction of rigid crosslinks was shown to disrupt crystallinity of PEEK very efficiently. Because tensile properties of PEEK depend on its crystallinity, we observed a decrease in properties such as Young's modulus and the ultimate elongation, the extent of which depended on the degree of crosslinking. We also observed an improvement in the elastomeric properties of the crosslinked materials, such as decrease in initial permanent set during high temperature cyclic tensile testing. Mechanical creep behavior at high temperature also improved for crosslinked polymers vs the original commercial Victrex 151G in terms of a reduced irreversible creep component. All crosslinked materials showed excellent resistance to hot oily, acidic and basic environments, as well as excellent thermal stability. Overall, we were able to synthesize "softer" materials that are more rubbery at high temperature than commercial thermoplastic Victrex 151G; these elastomer-like materials showed promising mechanical properties for high temperature applications in hot/corrosive environments.
2016
Polyester polyols from renewable resources have gained significant interest in the field of polyurethane chemistry. Two sets of segmented TPUs were prepared from crystalline and amorphous azelate polyols, 4,4 0-methylenebis(phenyl isocyanate), and 1,4-butanediol as a chain extender at a mole ratio of 1:2:1, respectively. Bio-1,3-propanediol (1,3-PDO) and 1,5-pentanediol (PTDO) were used to prepare crystalline azelate polyols, while 1,2-propanediol (1,2-PDO) and 2,2 0-dimethyl-1,3-propanediol (NPG) were used to prepare amorphous azelate polyols. All TPUs displayed clear glass transition temperatures (T g s) in between −36 and − 24 C, associated with azelate polyols soft segments, which are decreasing with increasing diols chain lengths in azelate polyols. TPUs based on crystalline azelate polyols exhibited higher mechanical properties and better heat resistance in comparison to their counter parts. Besides, TPU based on 1,3-PDO azelate showed lower percentage of hysteresis indicating lower heat build-up. This is essentially good for TPUs that are to be used in dynamic applications such as rollers and wheels. Hence, the study on structure-property correlation of the crystalline and amorphous azelate polyols and their effect on TPUs properties suggest that crystalline azelate polyols are suitable for dynamic application of TPU, and amorphous azelate polyols are suitable for coatings and adhesives applications.
Polymers, 2019
In this study, we enhanced the toughness of epoxy resin by blending it with the diblock copolymer poly(ethylene oxide–b–ε-caprolactone) (PEO-b-PCL) with a benzoxazine monomer (PA-OH) as the thermal curing agent. After thermal curing, Fourier transform infrared spectroscopy revealed that intermolecular hydrogen bonding existed between the OH units of the epoxy–benzoxazine copolymer and the C–O–C (C=O) units of the PEO (PCL) segment. Differential scanning calorimetry and dynamic mechanical analysis revealed that the glass transition temperature and storage modulus of the epoxy–benzoxazine matrix decreased significantly upon increasing the concentration of PEO-b-PCL. The Kwei equation predicted a positive value of q, consistent with intermolecular hydrogen bonding in this epoxy–benzoxazine/PEO-b-PCL blend system. Scanning electron microscopy revealed a wormlike structure with a high aspect ratio for PEO-b-PCL as the dispersed phase in the epoxy–benzoxazine matrix; this structure was re...
Thermal and dynamic mechanical analysis of cross-linked poly(esterurethanes)
Journal of Thermal Analysis and Calorimetry, 2007
New cross-linked poly(esterurethanes) (PEU) based on unsaturated olygo(alkyleneester)diol (OAE), 4,4'-diphenylmethane diisocyanate (MDI) and styrene or methyl methacrylate as curing monomers were prepared. The synthesis of PEU was performed in two steps. In the first step OAE was obtained from adipic acid, maleic anhydride and ethylene glycol. In the second step a prepolymer was obtained in a reaction of OAE with different amounts of 4,4'-diphenylmethane diisocyanate followed by crosslinking using previously mentioned curing monomers. The influence of structure of the poly(esterurethanes) on thermal and dynamic mechanical properties is studied. Thermogravimetric analysis shows that cross-linked poly(esterurethanes) demonstrate high thermal stability. Moreover the dynamic mechanical thermal analysis shows that the presence of styrene cross-linking chains in polymers lead to the phase separation in cross-linked poly(esterurethanes).
Synthesis and characterization of poly(ester ether siloxane)s
Polymer International, 2006
A series of novel thermoplastic elastomers based on ABA-type triblock prepolymers, poly[(propylene oxide)–(dimethylsiloxane)–(propylene oxide)] (PPO-PDMS-PPO), as the soft segments, and poly(butylene terephthalate) (PBT), as the hard segments, was synthesized by catalyzed two-step melt transesterification of dimethyl terephthalate (DMT) with 1,4-butanediol (BD) and α,ω-dihydroxy-(PPO-PDMS-PPO) (M̄n = 2930 g mol−1). Several copolymers with a content of hard PBT segments between 40 and 60 mass% and a constant length of the soft PPO-PDMS-PPO segments were prepared. The siloxane-containing triblock prepolymer with hydrophilic terminal PPO blocks was used to improve the compatibility between the polar comonomers, i.e. DMT and BD, and the non-polar PDMS segments. The structure and composition of the copolymers were examined using 1H NMR spectroscopy, while the effectiveness of the incorporation of α,ω-dihydroxy-(PPO-PDMS-PPO) prepolymer into the copolyester chains was controlled by chloroform extraction. The effect of the structure and composition of the copolymers on the transition temperatures (Tm and Tg) and the thermal and thermo-oxidative degradation stability, as well as on the degree of crystallinity, and some rheological properties, were studied. Copyright © 2006 Society of Chemical Industry
Poly(ether–ester)s modified with different amounts of fumaric moieties
Polymer, 2002
A series of novel poly(ether±ester)s modi®ed with fumaric moieties is synthesized by transesteri®cation in the melt of dimethyl terephthalate (DMT), dimethyl fumarate (DMF), 1,4-butanediol (BD) and poly(tetramethylene oxide) (PTMO, M Å n 1000 g/mol). The effect of the introduction of double bonds into both the hard and soft segments and their content on the structure and the thermal and rheological properties of the synthesized polymers are investigated. The introduction of double bonds into the polymer main chains increases the molecular weight of the copolyesters, but reduces the crystallinity of the hard segments and related properties such as modulus and hardness. The presence of double bonds improves the high temperature properties and thermal stability, especially the thermo-oxidative one, lowers the melting and crystallization temperature and increases the glass transition temperature. The incorporation of fumaric moieties into the macrochains improves the adhesive strength of the polymer to a metal surface. q
Journal of Polymer Science Part B, 2001
Thermoplastic polyimide (TPI) was synthesized via a traditional one-step method using 2,3,3 ,4-biphenyltetracarboxylic dianhydride (3,4-BPDA), 4,4-oxydianiline (4,4-ODA), and 2,2-bis(trifluoromethyl)benzidine (TFMB) as the monomers. A series of semi-interpenetrating polymer networks (semi-IPNs) were produced by dissolving TPI in bisphenol A dicyanate (BADCy), followed by curing at elevated temperatures. The curing reactions of BADCy were accelerated by TPI in the blends, reflected by lower curing temperatures and shorter gelation time determined by differential scanning calorimetry (DSC) and rheological measurements. As evidenced by scanning electron microscopy (SEM) images, phase separation occurred and continuous TPI phases were formed in semi-IPNs with a TPI content of 15% and 20%. The properties of semi-IPNs were systematically investigated according to their glass transition temperatures (T g), thermo-oxidative stability, and dielectric and mechanical properties. The results revealed that these semi-IPNs possessed improved mechanical and dielectric properties compared with pure polycyanurate. Notably, the impact strength of semi-IPNs was 47%-320% greater than that of polycyanurate. Meanwhile, semi-IPNs maintained comparable or even slightly higher thermal resistance in comparison with polycyanurate. The favorable processability and material properties make TPI/BADCy blends promising matrix resins for high-performance composites and adhesives.