无规共聚/均聚聚丙烯的发泡行为及其发泡材料的力学特性

Foaming behaviors of random copolymerization/homopolymerization polypropylene and the mechanical properties of its foaming materials

将均聚聚丙烯T03和无规共聚聚丙烯E02ES进行共混改性得到系列无规共聚/均聚聚丙烯(E02ES-T03),运用超临界CO_(2)模压发泡实验、DSC、SEM和力学测试表征技术,系统地研究了E02ES-T03的发泡性能、及其发泡材料的力学特性。研究发现,T03含量的增加提高了聚丙烯试样的熔融温度和结晶度,使其发泡上下限温度均有所提高。当T03加入量低于20wt.%时,E02ES-T03发泡温度上下限的提高幅度相近,发泡窗口与E02ES相近;而当T03含量高于20wt.%时,发泡下限温度有显著提高,使得聚丙烯试样发泡窗口收窄,所得高倍率(20倍)发泡材料泡孔尺寸不均匀性、具有高开孔率(大于50%)。T03含量为20wt.%的发泡材料因其较为完整的泡孔结构和较大的结晶度,表现出优异的强度和模量,较之发泡E02ES,压缩强度、弯曲强度和拉伸强度的增幅在30%至100%。

Homopolymerization polypropylene T03 and random copolymerizationpolypropylene E02ES were blended to obtain a series random copolymerization/homopolymerization polypropylene(E02ES-T03),and foaming behaviors of E02ES-T03 and mechanical properties of its foaming materials were studied by supercritical CO_(2) molded foaming experiment,DSC,SEM and mechanical tests.The results show thatthe foaming up-limit temperatureand low-limit temperature of E02ES-T03 are increased with T03 content increasing,resulting from the increase of melting temperature and cryst allinity.When theT03 content is below 20 wt.%,the foaming window of E02ES-T03 is similar to E02ES.However,when the T03 content is over 20 wt.%,the foaming window of polypropylene samples is narrowed and their high foaming ratio(20 folds)foamsshow uneven pore-size and high interconnectivity(over 50%),for the foaming lower limit temperature is significantly improved.The foamed polypropylene with 20 wt.%of T03exhibits excellent intensity strength and modulus due to its relativ ely complete pore structure and high crystallinity,and compared with foamed E02ES,its compressive strength,bending strength,and tensile strength is increased by 30%to 100%.