聚四氟乙烯的辐射效应与结晶性质之间的相互影响

MUTUAL INFLUENCE BETWEEN THE RADIATION EFFECT ON STRUCTURE AND THE CRYSTALLIZATION BEHAVIOR OF POLYTETRAFLUOROETHYLENE

用电子显微镜(TEM、SEM),偏光显微镜,电子衍射(E.D)和示差扫描量热(DSC)等方法研究了^(60)Coγ辐射聚四氟乙烯(PTFE)的结晶行为。结果表明,PTFE晶体的形态随辐照剂量增大呈有规律的变化。经辐照过的PTFE晶体可以产生表面晶体、针晶十球晶、棒晶、单晶、球粒结构五类结晶形态。它们的结晶过程不仅与辐照条件有关,而且与PTFE晶体的完整性有关。这些结果与DSC测得的结晶性质之间存在对应关系。电镜图象表明,辐照过的晶体存在有序微区,它在结晶时起晶核作用。同一晶体辐照的不均一性,道明一个完整的晶格有抗γ射线的能力。

The structures and crystallization behavior of polytetrafluoroethy-lene (PTFE) were studied with electronoptical microscope, electron diffraction and di-fferential scanning calorimetry (DSC) techniques respectively. It was shown that themorphology of PTFE depends not only on the radiation intensity, but also on cry-stalline perfectness of PTFE. The irradiated PTFE had five kinds of typical structuremorphology including, to the surface crystals, needle-like+spherulite, rodlike. singlecrystals and spheric particles. These results were correlated with DSC crystallizationcurves very well. From electron pattern it is demonstrated that in these irradiated crystals there exi-sts some ordered regions, which act as nucleus of crystal. This indicated that withinsome range of dose, the inhomogenous distribution of irradiation of the same crystal,enables a perfect crystal lattice to have higher resistance to γ irradiation.