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The polymer/nano-inorganics composite microsphere possesses excellent application prospects, but it is difficult to resolve the problem of the aggregation of nano-inorganic particles in polymer and the affinity between inorganics and polymer matrix. In this study, the preparation and characterization of polystyrene (PS)/ethylene vinyl acetate copolymer (EVA)/CaCO3 microspheres fabricated via a novel phase inversion emulsion process are described. By this one-pot method, the PS/EVA/CaCO3 microspheres are obtained by firstly converting styrene monomer containing EVA and nano CaCO3 into droplets dispersed in water with help of emulsifiers and a following polymerization. Because the inorganic nanoparticles are ultrasonically dispersed in liquid monomer mixture before the polymerization, the aggregation of nano-inorganic particles could be prevented to a great extent. The EVA is designed to enhance toughness of polystyrene matrix and increase the affinity between polymer and inorganic particles. The morphological structure of PS/EVA/CaCO3 microspheres is that nano CaCO3 particles are embedded both in the interior and on the surface of the microspheres. The micro-sized PS/EVA/CaCO3 microspheres showed a significantly improved mechanical property and a better heat resistance. This technique also offers the possibility for fabricating many kinds of new and useful polymer/inorganic microspheres with tailored performance by using special monomers and inorganic particles. [ABSTRACT FROM AUTHOR]

In this paper, the effects of fiber shape, fiber distribution, fiber size and fiber hybridization on the tensile properties of short sisal fiber-reinforced polypropylene composites were studied by the generalized method of cells and laminate analogy approaches. It is found that the fiber distribution has a large effect on the axial Young’s modulus. The fiber shape and fiber size have stronger influences on the transverse Young’s modulus and axial Poisson’s ratio than the fiber distribution. The fiber type hybridization and fiber shape are shown to be important factors in affecting the axial shear modulus. Hybridization with glass fiber is found to be an efficient method of creating high-performance composites. [ABSTRACT FROM AUTHOR]

The main objective of this article was to study the capillary effects during the impregnation of polypropylene resin in the jute fiber mats. The static equilibrium contact angles between polypropylene matrix and fibers were measured and the dynamic impregnation of matrix in the fiber mats was researched in detail. The results show that the static contact angles are clam-shell shape. The capillary effects present little values in the dynamic impregnation. The preparation for low void composites should be performed below the critical resin flow velocity of 0.13 µm/s for polypropylene resin and 0.21 µm/s for polypropylene/maleated polypropylene blend resin, respectively. [ABSTRACT FROM AUTHOR]

In this article, the microstructures of sisal fiber composites were analyzed. The porous structure of sisal fiber, crystalline morphology of matrix and fiber distribution in composites were characterized by Voronoi diagram. The tensile properties of composites were also measured. The results show that the maleated polypropylene compatibilizer can accelerate the formation of transcrystalline interface between fibers and matrix. Improvement of interface adhesion and reduction of fiber polarity can lead to better fiber distribution in the matrix. The tensile moduli of composites are related to the degree of fiber distribution. [ABSTRACT FROM AUTHOR]