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1.
Two kinds of aliphatic alternating polyesteramide prepolymers were prepared through melt polycondensation from N,N’-bis(2-hydroxyethyl)-adipamide and adipic acid or sebacic acid. Chain extension of them was conducted with 2,2′-(1,4-phenylene)-bis(2-oxazoline) and adipoyl biscaprolactamate as combined chain extenders. The chain extended polyesteramides (ExtPEAs) were characterized by IR, 1 H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide angle X-ray scattering, tensile test and enzymatic degradation. The results showed that the ExtPEA(4,m)s were mainly constituted with the diester adipamide alternating units. ExtPEA(4,4) and ExtPEA(4,8) had Tm of 83.8℃ and 85.8℃ and initial decomposition temperature above 310.0℃. They crystallized similarly as Nylon-66 did and were flexible thermoplastic materials with tensile strength up to 25.64 MPa and strain at break up to 737%. 相似文献
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Two polyborosiloxanes(PBSis) with char yield up to 74.13% at 800 °C were synthesized by the direct polycondensation of boric acid with phenyltrimethoxysilane in diglyme. The PBSis were characterized by gel permeation chromatography, IR spectroscopy as well as1H-,29Si- and11B-NMR. PBSi modified phenol-formaldehyde resins(PBSi/PFs) were prepared at different PBSi/PF mass ratios and were cured at 150 °C. The PBSi/PFs were characterized by IR spectroscopy, scanning electron microscopy, thermogravimetric analysis and tensile test. The results revealed that the cured PBSi/PFs had sea-island morphology and higher char yield than the common PF. PBSi/PF blend with PBSi/PF mass ratio of 0.4:1 had char yield up to 70.83% at 800 °C. The PBSi/PFs had tensile strength similar to PF. The ceramization of PBSi/PFs was also studied. The silicon boron oxycarbide(SiBOC) ceramics formed were characterized by IR spectroscopy and elemental analysis. This method provided a valuable way to prepare easily shapeable polymer blends as ceramic precursors. 相似文献
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合成生物降解性聚酯研究的进展 总被引:20,自引:0,他引:20
对近年来采用化学法,主要是缩合聚合法及开环聚合法,合成生物降解性聚酯的研究进展作了综述。 相似文献
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A non-isocyanate route for synthesizing thermoplastic polyurethanes with excellent thermal and mechanical properties was described. Melt transurethane polycondensation of 1,6-bis(hydroxyethyloxy carbonyl amino)hexane with four poly(ethylene glycol)s(PEGs), i.e. PEG400, PEG600, PEG1000, or PEG1500, was conducted at different molar ratios. A series of thermoplastic poly(ether urethane)s(TPEUs) with long PEG sequences were prepared. The TPEUs were characterized via gel permeation chromatography, FTIR, 1H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide-angle X-ray scattering, and tensile tests. The TPEUs exhibit Tg between 12.4 °C and-40.4 °C, Tm of up to 149.8 °C, and initial decomposition temperature over 239.4 °C. The tensile strength of the TPEUs reaches 38.39 MPa with a strain at break of 852.92%. 相似文献
6.
将乙酰丙酮(AcAc)、乙酰乙酸乙酯(AcAcE)、苯甲酰基丙酮(BzAc)作为β-二羰基基团通过烷基化反应,引入到氯甲基聚苯乙烯(PSt-CH2Cl)微球,研究了该微球在硝酸铈铵(CAN)存在下引发丙烯酰胺(AAM)的接枝聚合,以接技前后β-二羰基功能化聚苯乙烯微球吸水率及氮含量的变化、颗粒的增重、ESCA及FT-IR光谱、显微照相等方法,对接枝聚合物进行了表征,并提出了接技聚合反应的机理. 相似文献
7.
β-二酮或β-三酮对铈(Ⅳ)盐引发烯类单体聚合的影响 总被引:1,自引:0,他引:1
研究了β-二酮或β-三酮(如:3-苄基乙酰丙酮、苯甲酰基丙酮、二苯甲酰基甲烷及3-苯甲酰基乙酰丙酮)对铈(Ⅳ)盐引发丙烯酰胺聚合的促进作用,测定了聚合反应速度及表现活化能,表明铈(Ⅳ)盐/β-二酮或β-三酮可组成活性很高的氧化还原体系;采用自旋捕捉技术及ESR谱研究了体系的初级自由基结构;通过FTIR光谱端基分析检测到这类体系引发丙烯腈所得聚合物端基有β-二酮结构。以此为基础,提出了这类体系引发烯类单体聚合的机理。 相似文献
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将乙酰丙酮、乙酰乙酸乙酯、苯甲酰基丙酮作为β-二羰基基团通过烷基化反应,引入到氯甲基聚苯乙烯微球,研究了该微球在硝酸铈铵存在下引发丙烯酰胺的接枝聚合,以接枝前后β-二羰基功能化聚苯乙烯微球吸水率及氮含量的变化、颗粒的增重、ESCA及FT-IR光谱,显微照相等方法对接枝聚合物进行了表征,并提出接枝聚合反应的机理。 相似文献
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A simple non-isocyanate route is developed for synthesizing crystallizable aliphatic thermoplastic poly(ester urethane) elastomers(TPEURs) with good thermal and mechanical properties. Three prepolymers of1,6-bis(hydroxyethyloxycarbonylamino) hexane(BHCH), i.e. Pre PBHCHs, were prepared through the self-transurethane polycondensation of BHCH. A poly(butylene adipate) prepolymer(Pre PBA) with terminal HO― groups was prepared and used as a polyester glycol. A series of TPEURs were prepared by the co-polycondensation of the Pre PBHCHs with Pre PBA at 170 ℃ under a reduced pressure of 399 Pa. The TPEURs were characterized by gel permeation chromatography, FTIR,1H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide-angle X-ray diffraction, atomic force microscopy, and tensile test. The TPEURs exhibited M_n up to 23300 g/mol, M_w up to 51100 g/mol, Tg ranging from-33.8 ℃ to-3.1 ℃, T_m from 94.3 ℃ to 111.9 ℃, initial decomposition temperature over 274.7 ℃, tensile strength up to18.8 MPa with a strain at break of 450.0%, and resilience up to 77.5%. TPU elastomers with good crystallization and mechanical properties were obtained through a non-isocyanate route. 相似文献
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淀粉乙酸酯的阴离子接枝己内酯聚合研究 总被引:5,自引:0,他引:5
将淀粉在二甲基甲酰胺、吡啶存在下 ,以乙酸酐进行部分乙酰化 ,制备取代度为 0 7~ 1 9的淀粉乙酸酯 (St Ac) .以萘钠与淀粉乙酸酯中残余的羟基反应 ,将羟基转化为醇盐 (ONa) ,引发己内酯进行阴离子开环接枝聚合 ,合成了淀粉 聚己内酯接枝共聚物 (St g PCL) .采用凝胶渗透色谱法 (GPC)研究了接枝前后聚合物分子量的变化情况 ,并以接枝率、单体转化率对接枝反应进行了表征 .研究了接枝条件如温度、溶剂、引发剂和单体的用量对接枝率及单体转化率的影响 .研究发现随着反应温度升高 ,接枝率、单体转化率呈S曲线变化 ,单体浓度、引发剂浓度的增大有利于接枝反应的进行 . 相似文献