The weld strength and phase structure of an ABS/PBT alloy was studied by using glycidyl methacrylate modified polymer as the compatibilizer. Both the weld strength and notched izod impact strength of the blend containing the compatibilizer was shown to be much higher than that of the non compatibilized blend.
The phase structure of the blends containing the compatibilizer showed better dispersion of rubber particles compared with the non compatibilized blend which showed rubber agglomeration. Rubber dispersion in blends became proportionally better as the compatibilizer content was increased from 5 to 15 percent.

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The weld strength and phase structure of an ABS/PA 6 alloy was studied by using acrylic acid modified SAN as the compatibilizer. Both the weld strength and the notched izod impact strength of the blend containing the compatibilizer was shown to be much higher than that of the non-compatibilized blend.
The phase structure of the blend containing the compatibilizer showed better dispersion of rubber particles compared with the non-compatibilized blend which showed agglomerated rubber particles. The X-ray diffraction patterns of a 60% drawn sample showed a non-oriented ring pattern for the PA 6 in the non-compatibilized blend.
On the other hand the compatibilized blend showed an oriented fiber pattern for the PA 6. This suggests that the weld strength and the izod impact strength are affected by this difference in the phase structure due to the addition of the compatibilizer.

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The effects of surface treatment using four kinds of coupling agents for clinoptilolite-type zeolite powder have been investigated in zeolite/polycarbonate (PC) composites. The composites were prepared by mixing the surface-treated zeolite powder with PC using a plastometer at 280°C. The number-average molecular weight (M_n) of PC, measured by gel permeation chromatography, decreased from 24300 to 13300 with the addition of untreated zeolite. The magnitude of the storage modulus (E′) and the glass transition temperature (T_g) of the composite evaluated by dynamic viscoelastometry decreased with decreasing molecular weight of PC.
The PC polymer is depolymerized during the mixing process due to the acid catalysis of zeolite. In composites where the zeolite was surface-treated with silane coupling agents with epoxygroups and polyphenol, the M_n of PC only decreased to 20700 and 22100, respectively. The E′ and T_g of the composites containing these surface-treated zeolites were larger than those of the neat PC. The coupling agents prevented the acid catalysis of zeolite powder, thus the surface-treatment of zeolites are effective in the reinforcement of composites.

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The effects of surface treatment of metal nickel (Ni) particles by different agents have been investigated in composites with polycarbonate resin (PC). The composites were prepared by mixing the surface-treated Ni particle with PC using a plastometer at 280°C. For the composites containing non-treated Ni particles, the number-average molecular weight (M_n) of PC in the composites, measured by gel permeation chromatography, decreased from 24, 300 to 10, 800 at a mixing time of 60min. The magnitude of the storage modulus (E′) and the glass transition temperature (T_g) of the composites evaluated by dynamic viscoelastometry decreased with decreasing molecular weight of PC. These results suggest that the PC molecule is depolymerized during the mixing process due to the catalyst-like action of the Ni particles. On the other hand, we found that the surface treatment of Ni particles with tannic acid or silane coupling agents, prevented the decrease in the values of E′, T_g and M_n of the composites. This implies that the surface treatment may be an effective method for composites containing a filler with catalyst-like action on the polymer.

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The tribological properties of blends of polyamide 6 (PA 6) with the polyolefins including high density polyethylene (HDPE), low density polyethylene (LDPE), and polypropylene (PP) at various blend ratios and maleic anhydride (MAH) content were investigated and the wear morphology at the sliding interface was discussed. Tribological properties such as coefficient of friction and the specific wear rate against stainless steel disks were measured by using a pin-on-disk type tribological test apparatus. The wear surface of the polymer samples and the metal disks were observed by SEM and polarized microscope. Tribological properties obtained were related to the choice of polyolefins, blend ratio of PA 6/polyolefins and MAH content. Tribological results were explained through mechanisms such as the transfer of polymer films onto the metal disks and wear debris at the interface between polymer and metal. It was found that the unique tribological properties of PA 6/LDPE and PA 6/PP blends, lower coefficient of friction than those of the parent polymers, were mainly caused by the formation of roll debris of LDPE and PP which reduces the true contact area. Furthermore, very high wear rates of the blends with lower PA 6 contents were due to an abrasion effect of worn PA 6 particles at the interface.

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The agglomerate of particles and voids at the polymer-particle interface and the heterogeneous structure, have been characterized by scanning acoustic microscopy for polypropylene (PP)/ethylene vinyl acetate polymer blends (EVA) filled with modified calcium carbonate (CaCO₃). The relationships between the hoterogeneous structure and mechanical properties (tensile strength, elongation at break, impact strength) of the PP/EVA/CaCO₃ series were investigated.
Using ultrasonic images, the haterogeneous structure in the PP/EVA/CaCO₃ series was evaluated based on the binarization method. Polymer blends were prepared by mixing PP and EVA using a two-roll mill, then the PP/EVA mixture and various size CaCO₃ particulates were mixed on the same mill. Stearic acid was used as a modifier for CaCO₃.
By adding 2wt% EVA to PP, the heterogeneous structure decreased to about one-seventh the value of the PP/CaCO₃ blend. Furthermore, the heterogeneous structure in the modified CaCO₃ series was about one-thirtieth that of the unmodified blends. The tensile elongation at break depends on the heterogeneous structure, irrespective of CaCO₃ size and EVA content. However, it is recognized that impact strength depends on the heterogeneous structure and particle size. The impact strength of PP/EVA filled with small CaCO₃ particulates was greater than that with larger CaCO₃ particulates for the same heterogeneous structure.

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A recycle technique for cut waste of polypropylene (PP) nonwoven fabrics as a matrix material for fiber reinforced thermoplastic composites was investigated. Glass and carbon fibers were selected as representative reinforcements and thermoplastic composites were molded using a simple injection molding method. The effects of surface treatment of the reinforcements on tensile modulus and strength of molded composites were discussed based on SEM observation results of fracture surfaces. Moreover, spun maleic anhydride grafted PP was fed into the injection machine together with the waste PP and reinforcements as a binder. The results suggest that the injection molding method described herein shows promise for contributing toward the material recycling of waste products of PP nonwoven fabrics.

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High speed spinnings of sheath/core=Poly (ethylene terephthalate)/Polyethylene (PET/PE) and PE/PET bicomponent fibers were carried out and the tensile behavior of the as-spun fibers was investigated. The structure development of the PET component in the bicomponent fiber was enhanced whereas that of the PE component was suppressed in comparison with respective single component spinnings. The analyzed birefringence for PET and PE components in bicomponent fibers did not change by reversing the sheath-core arrangement of the components. Accordingly the initial Young's modulus of both the sheath/core=PET/PE and PE/PET fibers were similar. On the other hand, the elongation at break and tenacity of the PE/PET fibers were larger than those of the PET/PE fibers. A three-dimensional model analysis of the bicomponent fiber conducted assuming transverse isotropy suggested that the generation of tensile or compressive radial stress could cause such behavior in tensile testing. The necking behavior of the low-speed spun bicomponent fibers was analyzed in detail. The natural draw ratio was found to be governed by the molecular orientation of the PET component. The necking behavior was slightly affected by the presence of the PE component in that the different sheath-core arrangement caused different types of influence.

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