No abstract

SYNPOSISIn recent years, blend technologies have been developed to modify mechanical properties of polypropylene by dispersing discrete stress-concentrating polyamide microparticles in the continuous polypropylene matrix. The work presented here is concerned with the examination of fundamental relationships between blend morphologies and mechanical properties, especially plastic deformation mechanisms at high strain. Polyamide-6, polyamide-12, polyamide-12 plasticized with N-butyl-phenylsulfonamide, and polyamide-6 in situ embedded in a shell composed of polyamide-36,6 have been used as blend components in polypropylene blends containing 30 vol % of these polyamides. For modification of interfacial adhesion, maleic-anhydride-grafted-polypropylene has been added. When the yield stresses of polyamide and polypropylene are matched, large elongations at break of the resulting blends can be achieved. The influence of crazing, voiding, and shear yielding has been elucidated by transmission electron microscopic analysis of strained blend samples. 0 1995

No abstract

No abstract

Various anhydride‐terminated isotactic and atactic oligopropenes of number average molecular weights ranging between 1,000 and 10,000 g/mole, prepared by maleinating vinylidene‐terminated propene oligomers obtained with isospecific and nonstereospecific metallocene‐based Ziegler–Natta catalysts, have been evaluated as blend compatibilizers of polypropylene/polyamide‐6 (70 vol%/30 vol%) blends to study the role of blend compatibilizer molecular architecture. When added during processing, as shown by IR spectroscopic analysis, the anhydride‐terminated oligopropenes react with the amine‐terminated polyamide‐6 to yield polypropylene‐block‐polyamide‐6 in situ. Such block copolymers are efficient dispersing agents. While the polyamide dispersion in the polypropylene continuous phase is not affected by blend compatibilizer stereoregularities, both stiffness and yield stress as well as notched Charpy impact strength increase with increasing stereoregularities and molecular weights. With oligopropene molecular weights exceeding 1,150 g/mole, the average size of the dispersed polyamide microphases correlates with the volume fraction of the oligopropene‐block‐polyamide‐6 blend compatibilizer and the dicarboxylic acid anhydride/amine molar ratio.