聚三氟氯乙烯共混增韧改性及结构与性能

Toughening Modification of Poly(trifluorochloroethylene)and the Relationship Between Structures and Properties

通过不同相对分子质量聚三氟氯乙烯(PCTFE)复配来改善其耐应力开裂性,以期在不添加其他功能助剂的情况下改善韧性,从而最大限度保持其优良的光学透明性和介电性能。采用动态流变学研究了PCTFE共混体系的流变特性。结果表明,不同相对分子质量PCTFE共混相容性较好,随着高相对分子质量PCTFE含量的增加,共混物分子链缠结程度增加,分子链运动能力下降,共混体系更多表现为弹性行为。偏光显微镜和差示扫描量热结果表明,高相对分子质量PCTFE的加入使其晶体尺寸显著减小,结晶度有所降低。当高相对分子质量PCTFE用量为30%时,共混物冲击强度相比于未改性PCTFE提高了140%,呈现出韧性断裂特征。

Poly(trifluorochloroethylene)(PCTFE)is one of the most important thermoplastic fluororesins.Due to its regular molecular structure and large crystal size,the products are usually brittle,sensitive to notches and prone to stress cracking.In this paper,PCTFE with different molecular weight were blended to improve its cracking resistance,and the toughness is enhanced,without the addition of other functional aids.The dynamic rheology results of the PCTFE blends show that PCTFE with different molecular weight has good compatibility.When the PCTFE content of the higher molecular weight(that is,PCTFE-M)increases,the entanglement of the molecular chains is enhanced,resulting in the restriction of the molecular mobility.The results of polarized optical microscope(POM)and differential scanning calorimetry(DSC)exhibit that the crystal size and the crystallinity of PCTFE are decreased after the addition of PCTFE-M.When the content of PCTFE-M is 30%,the impact strength of the blends is 140%higher than that of unmodified PCTFE,exhibiting typical ductile fracture behavior.