超快扫描量热法研究纳米SiO2对聚丙烯在聚丙烯/聚苯乙烯共混物中受限结晶的影响  

Effect of Nano-SiO_2 Addition on Confined Crystallization of PP in PP/PS Blends Characterized by Fast Scanning Calorimetry

作　　者：李红梅[1] 杨榕[1] 姜菁 黄以能[1] 周东山 LI Hong-mei;YANG Rong;JIANG Jing;HUANG Yi-neng;ZHOU Dong-shan(Xinjiang Laboratory of Phase Transitions and Microstructures in Condensed Matter Physics, College of Physical Science and Technology,Yili Normal University,Yining 835000,Xinjiang,China;State Key Laboratory of Coordination Chemistry,School of Chemistry and Chemical Engineering,Nanjing University,Nanjing 210023,China)

机构地区：[1]伊犁师范学院物理科学与技术学院,新疆凝聚态相变与微结构实验室,新疆伊宁835000 [2]南京大学化学化工学院,配位化学国家重点实验室,南京210023

出　　处：《功能高分子学报》2018年第6期561-568,共8页Journal of Functional Polymers

基　　金：国家自然科学基金(21274059,21474049,51133002,21274060)

摘　　要：利用超快扫描量热仪(FSC)研究了聚丙烯(PP)在PP/聚苯乙烯(PS)(质量比20/80,表示为PP/PS(20/80),其余类推)共混体系中的结晶动力学过程,以及填充纳米二氧化硅(n-SiO_2)后其结晶动力学的变化,成功获得了各样品从玻璃化转变温度至熔点温度整个区间的等温结晶动力学曲线。研究表明:在PP/PS(20/80)共混物中PP以微米尺寸分散在PS主体中,受限结晶现象导致其结晶速率下降一个数量级,n-SiO_2的引入使样品中异相成核位点增多,同时减弱了两相界面上高分子链的受限作用,使得PP/PS/n-SiO_2(20/80/2)体系的总结晶速率相比PP/PS(20/80)体系增大,接近本体PP的结晶速率,提高了不相容共混物PP/PS的力学性能。Isothermal crystallization kinetics of polypropylene(PP)confined in a polypropylene/polystyrene(PP/PS(20/80))blend(m(PP)/m(PS)=20/80)was studied by fast scanning calorimetry(FSC)at a scanning rate up to 20 000 K/s over a wide temperature region from glass transition temperature to melting temperature.Due to the incompatibility,PP component was dispersed as micron droplets with an average size of 1μm in the PS matrix.Confined crystallization of PP droplets was observed by conventional differential scanning calorimeter(DSC)with multiple crystallization peaks during cooling.After the addition of nano-SiO 2 particles,no obvious change of the confined crystallization behavior was observed by DSC.With the new technique,FSC,by studying the total crystallization rate of PP at several annealing temperatures,the confined crystallization behavior of PP component in immiscible PP/PS blends was investigated,and one order of magnitude decrease of the crystallization half time of PP was observed,mainly due to the loss of heterogeneity in each PP droplet after dispersing in PS.By adding 2%mass fraction nano-SiO 2 particles in the blend,on one hand,more heterogeneous nucleation sites were introduced for PP component and the crystallization rate of PP was increased at higher temperatures where heterogeneous nucleation was dominating.On the other hand,some nano-SiO 2 particles were located at the interface between the continuous and dispersed phase,lowered the interfacial tension and increased the mobility of PP chains,thus increased the crystallization rate.From the isothermal crystallization kinetics of PP in PP/PS blends with and without nano-SiO 2,it was observed that the addition of nano-SiO 2 particles could partially suppress the confinement effect and increase the crystallization rate and crystallinity of PP in immiscible PP/PS blends,thereby improve the mechanical property of the blends.

关 键 词：聚丙烯 受限结晶 纳米颗粒 超快扫描量热 

分 类 号：O631[理学—高分子化学]