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聚醚醚酮 (PEEK)自英国 ICI公司开发并工业化以来 ,由于其优异的性能已在机械、航天等领域得到广泛应用 .但 PEEK的 Tg 只有 41 6K,影响了使用范围 .因此其它聚芳醚酮类聚合物相继被开发出来 .但这些聚芳醚酮的主链结构大都为全对位连接 ,使其熔点较高以至加工难度增大 .如果在聚合物主链结构中引入间位结构 ,则可在对玻璃化转变温度影响较小的情况下降低熔点来改善加工条件[1,2 ] .新型间位聚醚酮醚酮酮 (PEKEKm K)是其中一种 ,其玻璃化转变温度 Tg 为 41 7K,Tm 为 5 82 K.无论熔体结晶、冷结晶和溶剂诱变结晶 ,PEKEKm K都只出… 相似文献
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聚醚醚酮(PEEK)自工业化以来[1],由于其优异的性能已在机械、航天等领域得到广泛应用.各种聚芳醚酮类聚合物相继被开发出来.但以亲电缩聚路线制备聚醚醚酮醚酮(PEEKEK)的报道较少[2].本文以二苯醚和4-氟苯甲酰氯为主要反应试剂,采取付氏酰基化... 相似文献
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Poly(vinylidene fluoride) (PVDF) and poly(butylene succinate-co-24 mol% hexamethylene succinate) (PBHS), both crystalline polymers, formed melt-miscible crystalline/crystalline polymer blends. Both the characteristic diffraction peaks and nonisothermal melt crystallization peak of each component were found in the blends, indicating that PVDF and PBHS crystallized separately. The crystalline morphology and crystallization kinetics of each component were studied under different crystallization conditions for the PVDF/PBHS blends. Both the spherulitic growth rates and overall isothermal melt crystallization rates of blended PVDF decreased with increasing the PBHS composition and were lower than those of neat PVDF, when the crystallization temperature was above the melting point of PBHS component. The crystallization mechanism of neat and blended PVDF remained unchanged, despite changes of blend composition and crystallization temperature. The crystallization kinetics and crystalline morphology of neat and blended PBHS were further studied, when the crystallization temperature was below the melting point of PBHS component. Relative to neat PBHS, the overall crystallization rates of the blended PBHS first increased and then decreased with increasing the PVDF content in the blends, indicating that the preexisting PVDF crystals may show different effects on the nucleation and crystal growth of PBHS component in the crystalline/crystalline polymer blends. 相似文献
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含间位聚醚酮醚酮酮的合成与结晶 总被引:2,自引:0,他引:2
聚芳醚酮类聚合物因其综合性能优异而在高技术领域得到广泛应用.这些高聚物的主链大都为全对位连接,使其熔点较高以至加工难度增大.如果在聚合物主链中引入间位结构,则可在对玻璃化转变温度影响较小的情况下降低熔点来改善加工条件[1].含间位聚醚酮醚酮酮(PEKEKmK)也是其中一种.本文主要研究PEKEKmK的合成、基本物性与结晶行为.样品的合成与制备:单体4,4′双(对苯氧基)二苯甲酮按文献[2]方法合成.聚合物参照文献[3]合成.将粉末样品在油压机上熔融后快速取出投入冰水中淬火得无定形样品,或将熔融… 相似文献
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聚醚醚酮(PEEK)自八十年代初由英国ICI公司开发并工业化以来,由于其优异的性能已在机械、航天等领域得到广泛应用.但PEEK的Tg只有143℃,影响了使用范围.因此其它聚芳醚酮类聚合物相继被开发出来.但这些聚芳醚酮的主链结构大都为全对位连接,使其熔点较高以至加工难度增大.因此,高Tg和低Tm的聚芳醚酮的合成是一项很有意义的工作.如果在聚合物的主链结构中引入间位结构,则可在对Tg影响较小的情况下降低熔点来改善加工条件[1,2].新型间位聚醚酮醚酮酮(PEKEKK(T/I))也是其中一种.本文主要研究PEKEKK(T/I)的合… 相似文献
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The influence of cyanuric acid (CA) as an efficient nucleating agent on the crystallization behavior and morphology of biodegradable poly(ε-caprolactone) (PCL) was extensively studied in this work with several techniques for the first time. The nonisothermal melt crystallization behavior and overall isothermal melt crystallization rate of PCL were significantly enhanced by only a small amount of CA. The addition of CA apparently improved the nonisothermal melt crystallization peak temperature, overall isothermal melt crystallization rate, and nucleation density of PCL spherulites, but did not modify the crystallization mechanism and crystal structure of PCL, indicating that CA was an efficient nucleating agent for the crystallization of PCL. The possible nucleation mechanism of CA on the crystallization of PCL was also discussed on the basis of their crystal structures. 相似文献
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由于相对较高的价格、较慢的结晶速率、较弱的力学性能、较差的热稳定性、较窄的加工窗口和较慢的生物降解速率等自身的弱点,生物降解高分子材料并未如通用高分子材料一样得到广泛应用,制备以生物降解高分子为基体的纳米复合材料是有效的改性方法之一。本文结合作者近年来在生物降解高分子改性领域中的工作,对以笼型倍半硅氧烷(POSS)作为纳米填料改性左旋聚乳酸(PLLA)和聚ε-己内酯(PCL)的研究进行简单综述,POSS可有效提高PLLA和PCL基体的结晶速率和力学性能,并促进了聚合物基体的水解过程。 相似文献