共查询到19条相似文献,搜索用时 125 毫秒
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滑石粉的成核作用对尼龙66的力学性能及非等温结晶行为的影响 总被引:3,自引:0,他引:3
研究了滑石粉,尼龙66样品的力学性能及非等温结晶行,探讨了滑石粉的比表面积和表面改性对尼龙66力学性能和非等温结晶过程的影响。结果表明:滑石粉的加入改善了尼龙66的拉伸性能和弯曲性能,冲击性能下降,表面处理后的滑石粉更有助于尼龙66性能的改善;滑石粉的比表面积对拉伸性能和冲击性能影响不大,对弯曲性能有较大影响;滑石粉的异相成核作用可提高尼龙66的结晶温度,滑石粉比表面积的增加和表面处理更有利于尼龙66结晶温度的提高。 相似文献
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《合成材料老化与应用》2016,(3)
尼龙材料在工程塑料、纤维材料中占有重要的地位,且随着近年来合成长链尼龙单体生产的实现,其应用更受关注。尼龙材料的性能与材料的聚集态结构中结晶结构密切相关。成核剂是一种用于改变结晶型聚合物的结晶度和结晶形态,加快结晶速率并改善聚合物性能的加工助剂。常用的尼龙成核剂可以分为无机成核剂、有机成核剂、复合成核剂三类。该文以聚合物结晶理论和成核剂作用机理为基础,介绍不同种类成核剂的加入对尼龙的晶型、结晶速率、结晶度、拉伸强度、弯曲性能、冲击强度以及透明度等结构与性能上的影响。 相似文献
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采用折射率法测定了尼龙66盐在水中的溶解度,用激光自动检测晶体粒子出现的方法测定了尼龙66盐水溶液的结晶成核诱导期.对溶液结晶成核诱导期作了简单的分析与讨论,导出了结晶成核诱导期与相对过饱和度之间的关联式.根据公式,由实验数据还获得了尼龙66盐水溶液结晶成核级数值. 相似文献
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采用双螺杆挤出机熔融制备了聚丁烯–1(PB-1)/滑石粉复合材料,研究了滑石粉含量对PB-1熔融及结晶行为的影响。结果表明,滑石粉显著促进了PB-1的结晶过程,其成核能力在滑石粉质量分数为1%时最佳。非等温结晶动力学研究表明,在滑石粉的实验用量范围内(1%~10%),要达到相同的结晶度,PB-1/滑石粉复合材料的完成温度明显高于纯PB-1的完成温度。当滑石粉质量分数为1%~5%时,要达到相同的结晶度,PB-1/滑石粉所需的时间明显比纯PB-1短;当用量为7%时稍短;当用量为10%时又稍长。但滑石粉不影响PB-1的依热成核方式和三维生长机制。偏光显微镜结果表明滑石粉对PB-1的异相成核作用显著。广角X射线衍射研究表明滑石粉阻碍了PB-1由晶型Ⅱ向晶型Ⅰ的转变过程,使晶型转变变缓。 相似文献
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Effect of nucleating agents on the crystallization behavior and heat resistance of poly(l‐lactide)
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Xiuqin Zhang Lingyan Meng Gen Li Ningning Liang Jing Zhang Zhiguo Zhu Rui Wang 《应用聚合物科学杂志》2016,133(8)
Poly (l ‐lactide) (PLLA) blends with various nucleators were prepared by melt processing. The effect of different nucleators on the crystallization behavior and heat resistance as well as thermomechanical properties of PLLA was studied systematically by differential scanning calorimetry, X‐ray diffraction, heat deflection temperature tester, and dynamic mechanical analysis. It was found that poly(d ‐lactide), talcum powder (Talc), a multiamide compound (TMC‐328, abbreviated as TMC) can significantly improve the crystallization rate and crystallinity of PLLA, thus improving thermal–resistant property. The heat deflection temperature of nucleated PLLA can be as high as 150°C. The storage modulus of nucleated PLLA is higher than that of PLLA at the temperature above Tg of PLLA. Compared with other nucleating agents, TMC was much more efficient at enhancing the crystallization of PLLA and the PLLA containing TMC showed the best heat resistance. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42999. 相似文献
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X‐ray diffraction methods, DSC thermal analysis, and polarized light microscopy (PLM) were used to investigate the structural changes of nylon 66/clay nanocomposites. PA 66/clay nanocomposites were prepared by the method of melt intercalation. The results indicate that the addition of the intercalated organo‐montmorillonite (OMMT) can induce generation of the β‐form crystal of PA 66 and substantially affect the arrangement of molecules in the α‐form crystal, although the crystallinity scarcely changes. Also, the DSC results indicate that the addition of OMMT in the PA 66 matrix leads to increases of crystallization temperatures and the full width at half maximum (FWHM) of the exothermic peaks. Moreover, the viscosity factor is the main influence on FWHM of the exothermic peaks of PA 66/clay nanocomposites. The results of nonisothermal crystallization kinetics show that OMMT has the effect of heterogeneous nucleation and leads to the decrease of the size of the spherocrystal. The heterogeneous nucleation effects of OMMTs influence the mechanism of crystallization and the growth mode of PA 66 crystals. PLM photographs verify that the size of spherocrystal is decreased and visually confirm the theory of crystallization kinetics. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 756–763, 2005 相似文献
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The melting behavior and nonisothermal crystallization kinetics of pure polyamide 6 (PA 6) and its molecular composites with polyamide 66 (PA 66) were investigated with differential scanning calorimetry. The PA 6/PA 66 composites had one melting peak, whereas the coextruded PA 6/PA 66 blends had two melting peaks. With the addition of PA 66 to PA 6 via in situ anionic polymerization, the melting temperature, crystallization temperature, and crystallinity of PA 6 in the composites decreased. The half‐time of nonisothermal crystallization increased for a PA 6/PA 66 molecular composite containing 12 wt % PA 66, in comparison with that of pure PA 6. The commonly used Ozawa equation was used to fit the nonisothermal crystallization of pure PA 6 and its composites. The Ozawa exponent values in the primary stage were equal to 1.28–3.03 and 1.28–2.97 for PA 6 and its composite with 12 wt % PA 66, respectively, and this revealed that the mechanism of primary crystallization of PA 6 and PA 6/PA 66 was mainly heterogeneous nucleation and growth. All the results indicated that the incorporation of PA 66 into PA 6 at the molecular level retarded the crystallization of PA 6. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2172–2177, 2005 相似文献
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结晶特性对微发泡聚丙烯材料发泡行为的影响 总被引:1,自引:0,他引:1
以化学发泡注塑成型技术为主线,在二次开模条件下制备微发泡PP材料;通过DSC、XRD技术分析了结晶特性对微发泡聚丙烯材料发泡行为的影响。结果表明:结晶特性对气泡的成核、长大和定型过程具有明显的影响;添加滑石粉的改性PP材料结晶特性较差,发泡质量明显降低,泡孔直径和泡孔密度分别为36.98μm、3.29×107个/cm3;添加云母粉的改性PP材料具有合适的结晶温度和结晶度,发泡质量较理想,泡孔直径和泡孔密度分别为22.09μm、4.76×108个/cm3;能够获得泡孔细小、均匀的微发泡PP材料。 相似文献
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通过偏光显微镜和差示扫描量热仪(DSC)研究了碳纤维(CF)和滑石粉对聚酰胺6(PA6)结晶行为的影响。结果表明,CF的加入在PA6和CF的界面诱发横晶,CF和滑石粉在PA6基体中起到了异相成核作用,改变PA6的成核机理和晶体生长方式,提高了起始结晶温度和结晶速率。结晶速率随普等温结晶温度的升高而下降。当冷却速率增大时,起始结晶温度下降,结晶度增大。 相似文献
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To reveal the effect of the nigrosine dye, that the addition of the dye lowers the crystallization point (Tc) of molten polyamide resins with substantially no shift in the melting point (Tm), thus suppressing the crystallization enhancement of the crystalline nucleation agents, the characteristics of polyamide 66 (PA‐66) containing nigrosine dye EX (N‐EX) were investigated. Differential scanning calorimetry (DSC) analysis showed that the addition of N‐EX reduced the crystallization rate and Tc of molten PA‐66 with substantially no shift in Tm, and the crystallization enthalpy per unit of weight of PA‐66 was substantially constant. Tc of molten PA‐66 was lowered with an increase in the amount of N‐EX and reached its maximum at 13 wt % N‐EX. Dynamic mechanical analysis showed that the glass‐transition temperature and the secondary glass‐transition temperature increased with an increasing amount of the dye. On the other hand, the DSC and X‐ray diffraction results indicated that no dye molecule was present in the crystal structure of PA‐66. This effect of the nigrosine dye on PA‐66 is in contrast to those of crystalline nucleation agents, plasticizers, and antiplasticizers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3270–3274, 2006 相似文献