EVA的熔体皂化及其与PP动态硫化共混物的研究

Study on the Melt Saponification of EVA and its Dynamically Vulcanized PP/EVA Blends

为研究乙烯-醋酸乙烯共聚物(EVA)的熔体皂化并拓展其应用,直接将氢氧化钠和EVA熔体共混进行皂化反应制备皂化EVA,并以马来酸酐为交联剂,采用动态硫化技术将其同聚丙烯(PP)共混制备PP/EVA共混物。结果表明:熔体皂化可在EVA的侧链上生成游离的羟基;通过改变混炼时间、混炼温度和碱用量可实现EVA的可控熔体皂化。以皂化EVA为原料制备的PP/EVA共混物拉伸、冲击性能均高于PP/未经皂化处理的EVA共混物。当EVA的皂化度为49.5%时,PP/EVA共混物具有最佳的力学性能和熔体流动性。经EVA熔体皂化、动态硫化技术制备的PP/EVA共混物中EVA具有更好的分散效果。

Sodium hydroxide and melted ethylene-vinyl acetate copolymer （EVA） were mixed to preparesaponified EVA and the process of melt saponification of EVA was investigated. The saponified EVA wasblended with polypropylene （PP） to prepare dynamically vulcanized PP/EVA blends crosslinked with maleicanhydride. The results show that the EVA saponification degree can be controlled by changing the mixingtemperature, time and sodium hydroxide concentration. FT-IR and NMR results prove that free hydroxyl isdeveloped on the side chain of EVA by melt saponification. Moreover, saponification has a significant effect onthe properties of PP/EVA blends. The tensile and impact properties of PP/saponified EVA blends are higher thanthose of PP/unsaponified EVA blends. When the saponification degree of EVA is 49.5%, dynamicallyvulcanized PP/EVA blends show the best mechanical properties and melt flowability. The melt saponification ofEVA and dynamic vulcanization also improve the dispersion of EVA in PP/EVA blends.