热喷涂聚酰胺12/纳米SiO_2复合涂层的非等温结晶动力学

Non-isothermal crystallization kinetics of thermal sprayed polyamide 12/nano-SiO_2 composite coating

采用火焰喷涂法制备了聚酰胺12(PA12)及PA12/纳米SiO2复合涂层,利用差示扫描量热法(DSC)对PA12及其复合涂层的非等温结晶性能进行了分析,对所得的数据分别用Jeziorny法和Mo法进行处理。结果表明:用Jeziorny法和Mo法处理PA12及其复合涂层的非等温结晶过程比较理想;用Jeziorny法求出的Zc(结晶速率常数)和n(Avrami指数)均随冷却速率的增加而增加;而纳米SiO2的加入使复合涂层的Zc和n均大于纯PA12涂层,且使结晶半衰期缩短、结晶速率及结晶度增大。表明纳米SiO2具有明显的成核剂作用。

Coatings of polyamide 12 （PA12） and its composites with nanometer-sized silica （nano-SiO2） were prepared by a flame spraying process. The non-isothermal crystallization behaviors of the coatings were investigated by differential scanning calorimetry （DSC）. The DSC data for non-isothermal crystallization were analyzed by the Jeziorny and the Mo models. The result indicated that both the Jeziorny and the Mo methods can be suc- cessfully used to describe the non-isothermal crystallization behaviors of flame-sprayed PA12 and its composite coatings. The values of Zc（crystallization rate parameter） and n （Avrami exponent） determined by the Jeziorny method increased with increasing cooling rate. The values of Zc and n of composite coatings containing nano- SiO2 were higher than those of PA12, whilst the half-life of crystallization was higher and the crystallization rate and crystallinity were lower. Furthermore, it was found that nano-SiO2 in the PA12 coatings acted as an effective nucleation agent.