共查询到19条相似文献,搜索用时 62 毫秒
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超支化聚合物合成及其端基改性 总被引:8,自引:2,他引:6
超支化聚合物是近十几年得到快速发展的一种具有特殊大分子结构的聚合物。对超支化聚合物的发展简史、制备方法、端基改性及应用领域进行了评述。 相似文献
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超支化聚酯的合成及改性 总被引:10,自引:3,他引:10
以三羟甲基丙烷为核分子,二羟甲基丙酸为单体,合成了超支化聚酯。采用了IR、GPC、特性黏数和化学滴定等方法对产物进行了表征和分析。实验表明合成的超支化聚酯具有较窄的分子质量分布和较小的大分子流体力学半径,有类似球形的分子结构;得到的支化聚酯Mn=4.68×103g/mol,Mw=5.4×103g/mol,Mw/Mn=1.15,[η]=5.28 mL/g。进一步用油酸对聚合物进行改性,并研究了固含量与黏度的关系及其漆膜的性能;结果表明该树脂具有良好的成膜性和涂膜性能。 相似文献
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通过有核一步法,合成了端羧基超支化聚酯(CHP),然后与环氧氯丙烷经环氧化反应制备了端环氧基超支化聚酯(EHP),并制备了EHP改性环氧树脂(EP)体系。利用傅立叶变换红外光谱法、核磁共振氢谱法、凝胶渗透色谱法、差示扫描量热法、热变形温度分析、热失重分析、扫描电子显微镜等对EHP结构、改性EP体系固化工艺、力学性能、热性能等进行了研究。结果表明,合成了预期结构的EHP,数均分子量为1 908 g/mol,黏度为1 522.5 m Pa·s;当EHP含量为15 g时,改性EP体系的性能最佳,其冲击强度和弯曲强度分别为50.4 k J/m2,201.0 MPa,较改性前分别提高了213%,37%;热变形温度为147.5℃,热失重10%时的温度为360℃,较改性前分别下降了9%,7.7%。 相似文献
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The solution properties of hydroxyl terminated hyperbranched aliphatic polyesters and their acetyl derivatives have been studied by measuring viscosity parameters. The polarity of terminated groups of molecules is the most important factor affecting their properties. The intrinsic viscosity [η] cannot reflect the real monomolecular hydrodynamic volume of hydroxyl group-terminated hyperbranched polymer due to the strong intermolecular forces which lead to the formation of stable clusters. The intermolecular association constant KM depends not only on molecular weight, but also on the polarity of end-groups. However, the dynamic contact concentration CS can be determined accurately from reduced viscosity versus concentration plots. The reason why the intrinsic viscosity does not change linearly with the generation of the hyperbranched aliphatic polyesters is explained using ‘free-draining’ and ‘non-draining’ models. © 2001 Society of Chemical Industry 相似文献
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A hydroxyl‐functionalized hyperbranched polymer (HBP, H30) is used to modify 4,4′‐diaminodiphenylsulfone‐cured bisphenol‐A type epoxy resin and a separate phase structure of modified epoxy resins is observed. The effects of the H30 second phase size on the mechanical properties of modified epoxy systems are investigated systematically. The dependence of the toughening mechanisms on the HBP particle size is reported for the first time. It is shown that the nanosized H30 second phase is superior over microsized counterparts in modifying brittle epoxy resin. The tensile strength is slightly enhanced by the introduction of nanosized H30 second phase, whereas the strength is significantly reduced by the addition of microsized H30 phase. The failure strain and impact strength are obviously enhanced by the introduction of nanosized H30 second phase at low contents, whereas these properties are reduced by the addition of microsized H30 second phase at high contents. Finally, differential scanning calorimetric and thermogravimetric analyses are conducted to examine the effects of the HBP content on the glass transition temperature and the thermal stability, respectively. The glass transition temperature is slightly reduced while the thermal stability is not obviously influenced by the introduction of H30 second phase. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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将聚己内酰胺(PA6)与超支化聚合物(HBP)共混造粒、纺丝,研究了PA6/HBP共混物的流变性能及共混纤维的力学性能。结果表明:PA6/HBP共混物为非牛顿性假塑性流体,其表观黏度随着剪切速率的增大而减小;随着HBP含量增大,共混物非牛顿流动指数降低,剪切速率上升,加工温度降低;共混物黏流活化能随着HBP含量的增大而增大;PA6/HBP共混物较PA6结晶度提高,球晶明显细化;当w(HBP)为1.0%时,PA6/HBP共混纤维的断裂强度较纯PA6纤维略有降低,随着HBP含量的增加,共混纤维的力学性能明显降低。 相似文献
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Chi‐Jung Chang Shih‐Rong Hsieh Chung-Chi Wang Tsung‐Wei Hung Chih‐Chiao Hsieh 《Polymer International》2013,62(6):974-982
Hyperbranched polyurethanes with various lengths of linear segments between two branching points were synthesized by an A2 + B3 polymerization approach, where A2 is an aliphatic diisocyanate and B3 is a triol with three poly(ethylene glycol)–polycaprolactone diblock chains. The influences of the A2/B3 monomer ratio and the segment length on the gel point and thermal properties of the polymers were investigated. Crystallization behavior of the hyperbranched polymers can be controlled by tuning the segment length between two branching points. Surface restructuring is observed after oxygen plasma treatment because of the temperature effect and preferential etching effect. The effects of oxygen plasma treatment on the surface morphology, surface energy, surface chemical properties and postsurgical anti‐adhesion properties of hyperbranched polymer films were studied . 相似文献
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超支化聚酰亚胺的制备及其应用 总被引:1,自引:0,他引:1
综述了采用AB2型单体、A2 B3型单体、A2 B'B2型单体和AB AB2型单体合成超支化聚酰亚胺(HBPI)的制备方法,重点介绍了A2 B3型单体(包括二酐/三胺、二胺/三酐单体)制备HBPI的技术、HBPI的改性及应用领域和发展前景.HBPI具有较高的玻璃化转变温度和良好的溶解性能. 相似文献
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超支化大分子的最新应用进展 总被引:7,自引:0,他引:7
超支化大分子独特的构筑使其合成与应用在世界范围内受到人们越来越多的关注。笔者对最近以来国内外超支化大分子的最新应用进行了简要的综述,对今后超支化大分子的应用前景进行了展望和预测。 相似文献
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Hyperbranched polymer was synthesized from pentaerythritol (as the central core), 1,2,4‐trimellitic anhydride, and epichlorohydrin, and then hyperbranched polymer electrolytes with terminal ionic groups were prepared by the reaction of hyperbranched polymer with N‐methyl imidazole. The chemical structure, thermal behavior, and ionic conductive property of the hyperbranched polymer electrolytes were investigated by 1H‐NMR, FTIR, differential scanning calorimetry, thermogravimetric analyzer, and complex impedance analysis, respectively. The ionic conductivity of hyperbranched polymer electrolyte was up to 2.4 × 10?4 S cm?1 at 30°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献