PC/PET合金的制备及其耐溶剂机理

Preparation and Solvent Resistance Mechanism of PC/PET Alloy

采用聚对苯二甲酸乙二酯(PET)与聚碳酸酯(PC)共混方式提高材料的耐溶剂应力开裂能力,解决PC制品喷漆龟裂、开裂问题。研究了PET含量对PC/PET合金耐溶剂性能、力学性能、耐热和流动性能的影响。综合汉森溶解度参数、相对能量差异参数、溶剂聚合物渗透速率、晶态聚合物特性等研究了PC及PC/PET合金的耐溶剂机理。随着PET含量的增加,PC/PET合金的耐溶剂能力逐渐增强,力学性能降低,流动性变好,耐热性能变差。PET含量≥30份的PC/PET合金同时具有较好的耐甲苯和四氯化碳能力,PET含量≥40份时,PC/PET合金的125℃热球压压痕直径>2.0 mm,不能满足电工电子产品安规要求。非晶态聚合物的耐溶剂能力与相对能量差异参数(修正后的溶解度参数差异)、溶剂渗透速率及聚合物的应力状态有关。晶态聚合物具有较好的耐溶剂能力主要是因为分子排列规整,堆砌紧密,分子间相互作用力强,溶剂分子渗入聚合物内部困难。

polycarbonate(PC)/polyethylene terephthalate(PET)alloy was prepared by melt blending to improve the solvent stress cracking resistance(SSCR)of materials and solve the cracks in painting of PC products.The effects of the PET content on SSCR,mechanical properties,thermal properties and flowability of PC/PET alloy were studied.The mechanism of SSCR on PC and PC/PET alloy were studied by combining Hansen solubility parameters(HSP),relative energy difference(RED),solvent-polymer penetration rate and the characteristics of crystalline polymer.The results show that,with the increase of PET content,the SSCR of PC/PET alloy is enhanced gradually,the mechanical properties are lowered to a certain extent,the flowability becomes better,and the thermal property becomes worse.The PC/PET alloy with PET content≥30 phr has good resistance to toluene and carbon tetrachloride.However,the indentation diameter at 125℃of PC/PET alloy is over 2.0 mm when the PET content≥40 phr,which can not be accepted in terms of the safety requirements of electrical and electronic products.The solvent resistance of amorphous polymer is related to the RED number(i.e.the modified solubility parameter difference),the solvent penetration rate,and the stress state of the polymer.The solvent resistance of crystalline polymer is better mainly because it is difficult for solvent molecules to penetrate into the polymer due to regular arrangement and close packing among molecules,strong intermolecular interaction force,etc.