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Effects of processing conditions on the mechanical performance of maleic anhydride compatibilized in‐situ composites of polypropylene with liquid crystalline polymer
Author(s) -
Meng Y. Z.,
Tjong S. C.
Publication year - 1998
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.10068
Subject(s) - materials science , composite material , maleic anhydride , polypropylene , ultimate tensile strength , izod impact strength test , extrusion , polymer , scanning electron microscope , thermotropic crystal , polymer blend , molding (decorative) , injection moulding , copolymer , liquid crystalline
Maleic anhydride compatibilized blends of isotactic polypropylene (PP) and thermotropic liquid crystaline polymer (LCP) were prepared either by the direct injection molding (one‐step process), or by twin‐screw extrusion blending, after which specimens were injection molded (two‐step process). The morphology and mechanical properties of these injection molded in situ LCP composites were studied by means of scanning electron microscopy (SEM), Izod impact testing, static tensile, and dynamic mechanical measurements. SEM observations showed that fine and elongated LCP fibrils are formed in the maleic anhydride compatibilized in situ composites fabricated by means of the one‐step process. The tensile strength and modulus of these composites were considerably close to those predicted from the rule of mixtures. Furthermore, the impact behavior of LCP fibril reinforced composites was similar to that of the glass fiber reinforced polymer composites. On the other hand, the maleic anhydride compatibilized blends prepared from the two‐step process showed lower mechanical performance, which was attributed to the poorer processing behavior leading to the degradation of PP. The effects of the processing steps, temperatures, and compatibilizer addition on the mechanical properties of the PP/LCP blends are discussed.