不同方法制备的庚二酸钙对改性聚丙烯结晶和熔融行为的影响

摘要

Three types of calcium pimelate,D-CaPi,N-CaPi and S-CaPi,were prepared by a metadecomposition reaction,a neutralization reaction and physical compounding of pimelic acid with calcium stearate,respectively,and the effect of different types of calcium pimelate on crystallization and melting behaviors of polypropylene (PP) were investigated.The chemical structure of calcium pimelate was confirmed by Fourier-transform infrared spectroscopy,and the crystallization and melting characteristics of PP/calcium pimelate compounds were determined by differential scanning calorimetry.The results indicated that these three types of calcium pimelate exhibited a nucleation capability for the crystallization of PP,which leads to an increase in crystallization temperature by 4.9 ℃ for PP/D-CaPi and PP/N-CaPi compounds and 6.5 ℃ for PP/ S-CaPi compound.Moreover,S-CaPi was found much easier to induce β-form crystals for PP than D-CaPi and N-CaPi,and it could result in the formation of 84.5 ％ β-crystals for PP.%分别采用复分解反应法(D-CaPi)、中和反应法(N-CaPi)以及硬脂酸钙与庚二酸共混法(S-CaPi)3种不同方法制备了庚二酸钙,研究了3种庚二酸钙对聚丙烯结晶和熔融行为的影响.利用傅里叶变换红外光谱仪和差示扫描量热仪测试了庚二酸钙的结构及庚二酸钙改性聚丙烯的结晶和熔融行为.结果表明,3种制备方法都可以使庚二酸完全反应得到庚二酸钙;3种庚二酸钙对聚丙烯均有成核能力,其中D-CaPi和N-CaPi使聚丙烯结晶峰温度提高了约4.9℃,S-CaPi使聚丙烯结晶峰温度提高了6.5℃,同时,S-CaPi对于聚丙烯β晶型得诱导能力明显优于D-CaPi和N-CaPi,可使改性聚丙烯中的β晶型相对含量达到84.5％.