强紫外光作用下PVC／增韧剂体系结构与性能的演变

Microstructure and Properties Development of Impact-modified PVC During Photoageing

通过UV,FTIR,DSC及力学性能和色差的测试分析,实时追踪了在紫外光老化过程中,聚氯乙烯/氯化聚乙烯(PVC/CPE),聚氯乙烯/丙烯酸酯类共聚物(PVC/ACR)及聚氯乙烯/丙烯腈-丁二烯苯乙烯共聚物(PVC/ABS)体系的微观结构和宏观性能的演变过程.结果表明,在光老化过程中,ACR和CPE对PVC脱HCl生成共轭双键反应、氧化降解反应、交联反应及玻璃化转变温度(Tg)的变化等均有抑制作用,而ABS则对这些反应起促进作用.在宏观上表现为ACR和CPE的加入能提高体系的色泽稳定性,体系的力学性能保持率较高.而ABS的作用相反.

The effects of acrylonitrile-butadiene-styrene copolymer（ABS）, acrylic resin（ACR） and chloride polyethylene （CPE） on photodehydrochlorination, photooxidative degradation and photocrosslinking of poly（ vinyl chloride） （PVC） were investigated by UV-Vis, FTIR spectra and DSC. The gel content in exposed sample was estimated gravimetrically. The color change and mechanical properties of PVC during photoageing were also studied. It was found that compared with PVC, the polyene, the carbonyl and the gel content in both PVC/ ACR and PVC/CPE blends became much lower after irradiated by UV. The ATs of PVC/ACR blend and PVC/CPE blend were 79% and 24% lower than that of the blank, respectively. However, the reverse phenomena could be found in PVC/ABS blend. Especially, the gel content of PVC/ABS was much higher than that of PVC. These indicate that the addition of ACR and CPE decelerate photodehydrochlorination, photooxidation and photocrosslinking of PVC, while the addition of ABS accelerates the reactions. As a result, the PVC/ACR and PVC/CPE blends have higher color stability and mechanical properties than those of PVC/ABS blend during the photoageing.