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β晶型成核剂改性聚丙烯纤维研究 总被引:4,自引:1,他引:4
研究了含 0 .2 5 %β晶型成核剂 (酰胺化合物 )的聚丙烯 Z3 0 S及其纤维的力学性能、晶型结构和微观形态。通过纺丝 -拉伸实验和力学性能测试、广角 X射线衍射分析、SEM观察 ,发现成核改性后生成了β晶型聚丙烯 (K值约为 75 .3 % ) ,抗冲性能大幅度提高。β晶型聚丙烯在纺丝卷绕过程中发生了β晶型→α晶型转变 ,纤维中产生约 10 %微孔隙 ,改性纤维的力学性能有所降低。 相似文献
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β晶型成核剂对PP结晶行为的影响 总被引:1,自引:0,他引:1
制备了β晶型聚丙烯(β-PP),利用广角X射线衍射仪与偏光显微镜表征了球晶形态,研究了其非等温结晶行为,并用Jeziorny法、莫志深法和Kissinger法对所得数据进行处理。结果表明,添加β晶型成核剂后,PP由α晶型向β晶型转变,起始结晶温度明显提高,总结晶时间缩短,结晶活化能降低。β-PP的Avrami指数在1.69~1.89,小于PP,表明β晶型成核剂的加入改变了PP的成核机理及生长方式。 相似文献
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采用一种过渡金属化合物MB作为成核剂,考察了成核剂MB对聚丙烯性能的影响。通过偏光显微镜(PLM)和差示扫描量热仪(DSC)对MB的成核效果进行了表征。结果表明,成核剂MB较好地改善了聚丙烯的力学性能以及熔体流动性能,降低了聚丙烯球晶尺寸。 相似文献
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采用直接混合法制得等规聚丙烯(iPP)/分子筛体系和iPP/有机磷酸盐成核剂(NA11)/分子筛体系,研究不同种类分子筛在不同含量下对iPP结晶温度及力学性能的影响,进而研究不同分子筛在低含量下协同有机磷酸盐对iPP体系成核性能的影响,从动力学角度解释了提升原因。结果表明,单独添加分子筛制得的iPP体系,随着分子筛含量的增加,结晶性能和力学性能得到显著提升,不同分子筛对iPP性能的影响不同,ZSM-5型分子筛在含量为5%(质量分数,下同)以上具有促进iPPβ晶型生成的效果;采用直接混合法制得的不同分子筛复配有机磷酸酯钠盐NA11成核剂可提升iPP的力学性能;特别是当0.1%NA11和0.1%4A型分子筛一起添加到iPP中时,可在保证iPP具有较好刚性的同时兼具有良好的韧性,使iPP的弯曲模量提高35.2%、冲击强度提高14.4%,从而达到促进iPP材料刚韧平衡的效果。 相似文献
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The effect of biogenic extra cellular ice nucleators (ECINs) on gel‐forming capacity and textural stability of a fish actomyosin (AM) gel system subjected to controlled freeze‐thaw (FT) cycles was studied. Stability changes were quantified by measuring the degree of retention of Ca2+ ATPase activity and changes in protein surface hydrophobicity. Results showed that different concentrations of ECIN suppressed Ca2+ ATPase activity loss during FT cycles depended quantitatively on ECIN concentration. After three FT cycles, Ca2+ ATPase activity retention was 76.20% with the highest ECIN concentration and 20.10% without ECIN, and surface hydrophobicity of AM with ECIN was 150.67, whereas the corresponding value of the control sample was 208.70. By measuring changes in surface hydrophobicity, we observed that ECIN significantly reduces denaturation of AM protein caused by FT cycling. Our data show that ECIN contributes a significant protective effect on gel‐forming capacity of fish and textural stability of fish AM during FT cycling. This demonstrates for the first time that ECINs have the potential to help stabilise the texture of fish AM and potentially other food products during frozen storage. 相似文献