摘要
采用以化学键合方式在CaCO3表面包覆上聚丙烯蜡和将改性后的CaCO3先与EPDM复合、再与PP复合的工艺,制备PP/EPDM/CaCO3三元复合材料,以期在PP基体材料中得到EPDM包裹CaCO3的相结构.通过测量三元复合体系中各组分的表面张力,计算各可能组分对之间的界面张力和黏结功,分析三元复合体系中可能的相结构.热力学计算结果表明,三元复合体系中既存在以EPDM为壳、CaCO3为核的"核壳结构",又存在CaCO3与EPDM各自独立分散在PP基体中的结构.电镜照片进一步揭示,在PP/EPDM/改性CaCO3三元复合体系与PP/EPDM/未改性CaCO3三元复合体系中,这两种相结构的比例是不同的,在前者中以核壳结构为主.CaCO3表面性质的不同是产生这一差别的原因.由于这一结构差别的存在,PP/EPDM/改性CaCO3三元复合体系比PP/EPDM/未改性CaCO3三元复合体系具有更好的力学性能.当EPDM用量为8 phr、改性CaCO3用量为15 phr时,三元复合体系的冲击强度达14.25 kJ/m2,是纯PP的3.17倍.
Phase structure is one of the important influence factors to the properties of the polymer/elastomer/rigid filler ternary composite.In this paper,aiming to obtain the core/shell microstructure with calcium carbonate（CaCO3） particle as the core and ethylene-propylene-diene monomer copolymer（EPDM） as the shell in the ternary composite,the polypropylene（PP）/EPDM/CaCO3 composites were prepared using two techniques：surface modification of rigid filler and processing control.The modified CaCO3（PPW-CaCO3） was prepared by using a patent method,and the modified layer of lower molecular weight polypropylene（PPW） on the CaCO3 surface has the characteristics of chemical bonding.The processing control has a two-step procedure.First,EPDM was compounding in a twin-roll mill with raw CaCO3 or PPW-CaCO3 followed by pulverization.Secondly,the pulverized EPDM/CaCO3 or EPDM/PPW-CaCO3 powder was compounding with PP in a twin-screw extruder.The possible phase structures in the ternary composites were analyzed from the views of thermodynamics by measuring the surface tension of each constitute and calculating the interfacial tension and work of adhesion for all possible PP/EPDM,PP/CaCO3,EPDM/CaCO3 pairs in the ternary composites.The calculation results indicate that there are two kinds of possible phase structures existing in the ternary composites,one is the core/shell structure with CaCO3 particles as the rigid core and EPDM as the soft shell,another is CaCO3 particles and EPDM dispersing separately in PP matrix.However,SEM photos show that the proportions of the two structures in PP/EPDM/CaCO3 and PP/EPDM/PPW-CaCO3 composites are different,the core/shell structure mainly exists in PP/EPDM/PPW-CaCO3,resulting from the different surface properties of CaCO3.Because of the core/shell structure,the mechanical properties of PP/EPDM/PPW-CaCO3 ternary composites are better than those of PP/EPDM/CaCO3 ternary composites.When the content of EPDM is 8 phr and PPW-CaCO3 is 15 phr,the mechanical properties of composites are the best.The notched impact strength can reach 14.25 kJ/m2,which is 3.17 times higher than that of the PP matrix.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2008年第11期1061-1067,共7页
Acta Polymerica Sinica
基金
福建省科技厅(基金号2006F5031
2004J017)
教育厅基金(基金号JB06075)资助项目
关键词
碳酸钙
表面改性
聚丙烯
三元乙丙橡胶
相结构
力学性能
Calcium carbonate,Surface modification,Polypropylene,Ethylene-propylene-diene monomer copolymer,Phase structure,Mechanical properties
