硫酸钙晶须/TMB-5复合成核剂改性聚丙烯的结晶和熔融行为研究

摘要

采用硅烷偶联剂(KH-550)对硫酸钙晶须进行表面改性,对改性前后硫酸钙晶须的结构进行了红外光谱表征,运用差示扫描量热仪研究了β成核剂(TMB-5)、改性后的硫酸钙晶须(K-CSW)及K-CSW/TMD5复合成核剂改性聚丙烯(PP)的结晶和熔融行为,并着重研究了K-CSW与TMB-5在PP中的协同成核改性效果.结果表明,硅烷偶联剂已成功偶联于硫酸钙晶须的表面,K-CSW可有效促进PP β晶型的形成,且K-CSW与TMP5在PP中具有明显的协同成核效果,对PP结晶峰温度和β晶成核能力的提升也更加显著;当PP中TMB-5添加量为0.2％(质量分数,下同)、K-CSW添加量为2％时,改性后PP中β晶的相对含量高达90.1％,结晶峰温度从纯PP的122.3℃升高至127.2℃.%A surface modification of calcium sulfate whiskers was performed by using a KH-550 silane coupling agent,and their structures before and after the surface modification were investigated comparatively by Fourier-transform infrared spectroscopy.The crystallization and melting behaviors of polypropylene (PP) nucleated with β-nucleating agent (TMP-5),surfacemodified CaSO4 whiskers(K-CSW),and a mixture of CaSO4 whiskers and TMB-5 were studied by differential scanning calorimetry,and the nucleating effects of these three nucleating agents were compared.The results indicated that the K-CSW could effectively promote the formation of β-crystals and it also exhibited a synergistic nucleating effect with TMB-5,thus resulting in an improvement in crystallinity of PP.When 0.2 wt ％ of TMB-5 and 2 wt ％ of K-CSW were incorporated into PP,the relative content of β-crystals in PP reached 90.1％,and the peak crystallization temperature of nucleated PP increased to 127.2 ℃ from 122.3 ℃ of pure PP.