超临界二氧化碳协助丙烯酸丁酯固相接枝改性聚丙烯

以超临界CO2为溶胀剂和携带剂协助丙烯酸丁酯(BA)固相接枝改性聚丙烯(PP)。考察了超临界溶胀条件、接枝反应条件等因素对接枝产物PP-g-BA的接枝率和接枝效率的影响,通过傅里叶变换红外光谱、热重分析、示差扫描量热、扫描电子显微镜等方法对PP-g-BA进行了表征,并测试了PP-g-BA的接触角、熔体流动速率和力学性能。实验结果表明,在41℃、8.1MPa的超临界CO2中溶胀4h,再在80℃、常压下反应2h,得到接枝率为3.95%的极性PP。表征结果显示,BA接枝到了PP分子链上;PP-g-BA的熔点和表观结晶度明显下降;随接枝率的增加,PP-g-BA的热稳定性提高;与PP原料相比,接枝PP的接触角由98°降至72°,极性和亲水性明显改善;PP-g-BA的熔体流动速率和力学性能与原料的性能相近,接枝过程中PP几乎未降解。

Solid-Phase Grafting of Butyl Acrylate onto Polypropylene with the Aid of Supercritical Carbon Dioxide

Solid-phase free radical grafting of butyl acrylate(BA) onto polypropylene(PP) matrix was studied using supercritical CO2 as swelling agent and solvent carrier.Effects of swelling conditions and grafting conditions on grafting percentage of product PP-g-BA and grafting efficiency were investigated.The morphology and structure of the product were characterized by means of FTIR,SEM,DSC and TG.Besides,water contact angle,melt flow rate(MFR) and mechanical properties of PP-g-BA were measured.It was found that 3.95% of BA in PP-g-BA could be obtained under swelling conditions of 8.1 MPa,41 ℃ and 4 h,and the grafting conditions of atmospheric pressure,80 ℃ and 2 h.It was proved that BA could be grafted onto main chain of PP.Melting point and the crystallinity of grafted polymer obviously decreased.The water contact angle dropped from 98° to 72°,which indicated the polarity and hydrophilicity of PP were improved effectively.Measurements of MFR and mechanical properties of PP-g-BA showed that PP in it almost had not been degraded.The grafted product maintained the versatile mechanical properties of PP.