Kraton compatibilizers, adhesion

Microfibrils in the blend compatibilized with Kraton G probably formed by drawing of the rubbery shell of the core-shell particle. Important factors would have been the amount of rubber in the shell, the strength of the rubber, and the strength of adhesion to LLDPE. All these factors may have contributed in some degree to the high fracture stress and strain of the blend with Kraton G. The amount of compatibilizer in the shell differed for the various Kratons the thicker coating was certainly one of the reasons Kraton G gave better properties to the compatibilized blend than the Kraton D compatibiliz-ers. 

The scratch resistance of polypropylene was improved by blending 20 wt% PPE/HIPS blend (Noryl PX0844) as a modifier and 5 % styrene-ethylene/ propylene diblock copolymer (Kraton G) as a compatibilizer (Sue 2001, 2002). It appears that the fracture energy dissipation in the PP matrix occurs by craze promotion around the dispersed particles of PPE/HIPS blend and thus preventing crack formation, while the compatibilizer promoted the PP/PPE interfacial adhesion. 

Kraton FG1901X is used as the compatibilizer. This maleated SEBS (sty-rene-ethylene-butene-styrene) triblock presumably reduces the PE-PP interfacial tension to promote compatibilization by improving interfacial adhesion. 

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