烧结工艺对PTFE烧结程度影响  

Effects of Sintering Process on Sintering Degree of PTFE

作　　者：叶素娟 郭云龙 李国一 袁佳宇 黄兴 Ye Sujuan;Guo Yunlong;Li Guoyi;Yuan Jiayu;Huang Xing(Guangzhou Mechanical Engineering Research Institute Co.,Ltd.,National Engineering Research Center of Rubber and Plastic Sealing,Guangzhou 510700,China)

机构地区：[1]广州机械科学研究院有限公司,国家橡塑密封工程技术研究中心,广州510700

出　　处：《工程塑料应用》2020年第9期61-66,共6页Engineering Plastics Application

基　　金：国家重点研发计划项目(2018YFB200065-04);中国机械工业集团项目(SINOMAST-ZDZX-2018-05)。

摘　　要：采用差示扫描量热(DSC)法,研究烧结过程中不同烧结温度、保温时间和升温速率对聚四氟乙烯(PTFE)坯料烧结程度的影响。DSC分析表明,烧结温度过低,坯料表面区域的熔融曲线上出现低温和高温双重熔融峰且结晶度较高,此时坯料烧结程度不足。烧结温度过高或者保温时间过长,坯料表面区域的数均分子量显著降低,此时坯料过度烧结。升温速率过高,在熔融曲线上出现高温熔融峰且结晶度较高,此时坯料内部区域烧结程度不足。烧结程度的过低或过高,均会导致坯料结晶度和数均分子量的异常变化,造成坯料拉伸性能下降。当烧结温度为370℃、保温时间为20~140 min、升温速率为50~100℃/h时,坯料的结晶度和数均分子量降低率保持在较低水平,此时坯料烧结程度较理想。By means of differential scanning calorimetry(DSC),the effects of different sintering temperature,holding time and heating rate on the sintering degree of the polytetrafluoroethylene(PTFE)billets were studied.DSC analysis show that when the sintering temperature is too low,the melting curve of the surface area of the billet shows a double melting peak at low temperature and high temperature,and the crystallinity is high at the same time,so it can be considered that the degree of sintering of the billet is insufficient.When sintering temperature is too high or holding time is too long,the number average molecular weight of the surface area of the billet is significantly reduced,because the billet is over-sintered.If the heating rate is too high,the melting peak appears at a high temperature on the melting curve and the crystallinity is high,the degree of sintering inside the billet can be considered insufficient.Abnormal changes in the crystallinity and number average molecular weight of the billet will appear with too low or too high degree of sintering,resulting in a decrease in the tensile properties of the billet.When the sintering temperature is 370℃,the holding time is 20–140 minutes,and the heating rate is 50–100℃/h,the crystallinity and number average molecular weight reduction rate are kept at a low level.It can be considered that the sintering degree of the billet is ideal.

关 键 词：差示扫描量热法 聚四氟乙烯 烧结程度 结晶度 分子量 

分 类 号：TQ325.4[化学工程—合成树脂塑料工业]