DSC Analysis and Crystallization Behavior of the PTFE/SiO2 Composites
-
摘要: 采用DSC技术,研究不同热压温度制备的PTFE/SiO2复合材料以及纳米SiO2部分取代微米SiO2的PTFE/SiO2复合材料的非等温结晶行为。DSC分析表明热压温度高于370℃时,PTFE分子聚合度下降,晶态PTFE微观形貌发生改变,其性能恶化。对复合材料非等温结晶DSC曲线应用Avrami方程分析发现,结晶过程包含了均相成核和异相成核两种成核机理。纳米SiO2取代部分微米SiO2量小于0.25%时,对PTFE成核作用有一定提升,当取代量大于0.25%时,由于偶联剂用量一定,造成SiO2颗粒团聚以及与PTFE界面相容性变差,成核效果不明显。Abstract: By means of DSC, non-isothermal crystallization behavior of PTFE/SiO2 composite at different thermoforming temperature is investigated in which part of micro-SiO2 is replaced by nano-SiO2.The results of DSC analysis show that when the thermoforming temperature is higher than 370℃, as degree of polymerization decreases, microstructure of the crystalline PTFE changes and performance of the composites deteriorates.The non-isothermal crystallization DSC analysis of composites indicates that their crystallization process includes both homogeneous nucleation and heterogeneous nucleation.When the substitution is less than 0.25%, the nucleation is enhanced.When the substitution is more than 0.25%, the nucleation enhancemont is not obvious for SiO2 particle agglomeration and poor interfacial compatibility between the PTFE and SiO2.
-
Keywords:
- DSC /
- crystallinity /
- thermoforming temperature /
- avrami equation /
- heterogeneous nucleation
-
计量
- 文章访问数: 48
- HTML全文浏览量: 10
- PDF下载量: 3
下载:
