热处理对聚四氟乙烯-聚苯胺系列导电复合膜性能的影响

Influences of Heat-Treatment on the Performance of Series of Polytetrafluoroethylene-Polyaniline Conductive Composite Films

对电化学制备的聚四氟乙烯-聚苯胺系列导电复合膜进行热处理,采用热重、红外和X衍射等手段研究了在空气和真空氛围中,热处理对复合膜的电导率及力学性能的影响。热分析结果表明:此系列复合膜在100～180°C失重较少,在此温度区间内对聚苯胺-聚四氟乙烯复合膜热处理,其电导率在空气和真空氛围中均随热处理温度升高而下降,聚苯胺-聚四氟乙烯-银复合膜在空气氛围中的电导率也随热处理温度升高而下降,两种复合膜的强度不变,断裂伸长率降低;聚苯胺-聚四氟乙烯-银复合膜在真空氛围中经120°C热处理后电导率提高最显著,力学强度也有所提高,但断裂伸长率降低。X衍射研究表明复合膜经180°C热处理后结晶度降低。红外分析结果表明聚苯胺-聚四氟乙烯复合膜经180°C热处理,发生了磺基水杨酸的脱掺杂和聚苯胺的结构热氧化、分子链的断裂和交联,复合膜电导率降低。

A series of polytetrafluoethylene-polyaniline（PTFE-PANI） conductive composite films synthesized by electrochemical method were heat-treated in air or vacuum atmosphere.The conductivity and mechanical properties in different atmospheres were studied by thermogravimetric（TG） analysis,infrared ray（FT-IR） and X-ray diffraction（XRD）.TG results showed that the residual of mass of the composite film was minor from 100 °C to 180 °C.The conductivity of PTFE-PANI composite film dropped at the heat treatment temperature region in air and vacuum,so did the PTFE-PANI-Ag composite film in air.The mechanical strength of the series of composite films changed less,while the elongation at break reduced dramatically.The conductivity of PTFE-PANI-Ag composite film got a maximum in vacuum at 120 °C,and its mechanical strength improved while the elongation at break reduced.XRD spectra results showed that the crystallinity of PTFE-PANI film was lower after heat treatment at 180 °C in air.FT-IR spectra results showed that 5-sulfosalicylic acid dedoped from PTFE-PANI composite film,and benzene rings transformed into quinone by thermal oxidation.At the same time,thermal oxidation also caused break and cross-linking of the PANI molecule chain,therefore the conductivity of the films decreased.