The blends of thermoplastic polyether-based urethane elastomer (TPEU) and monomer casting polyamide 6 (MCPA6) were prepared using -caprolactam (CL) as a reactive solvent, and CL sodium as a catalyst at various TPEU contents (2.5-15 phr by weight). In situ anionic ring-opening polymerization and in situ compatibilization of TPEU/MCPA6 blends were realized in one step. The dissociated TPEU chains acted as macroactivator to initiate MCPA6 chain growth from the TPEU chains. The formed block copolymers (TPEU-co-MCPA6), which have been confirmed by Fourier transform infrared spectroscopy and 1 H-NMR analysis, improved the compatibility between TPEU and MCPA6. In addition, both differential scanning calorimetry and dynamic mechanical analysis studies revealed that the crystallinity temperature, melting temperature, the degree of crystallization, and the glass-transition temperature of MCPA6 component remarkably shifted to a low temperature with increasing TPEU content. Mechanical properties demonstrated that the impact strength and the elongation-atbreak of the blends significantly increased with the content of TPEU, whereas a progressive decrease occurred in tensile strength, flexural strength, and flexural modulus. WAXD spectra showed that only ␣-form crystal of PA6 component existed in the TPEU/MCPA6 blends. Furthermore, scanning electron microscopes (SEM) of the cryo-fractured surfaces confirmed a substantially improved compatibility, and reflected a seemly single-phase morphology. POLYM. ENG. SCI., 46: 1196 -1203, 2006.

Summary: In this work, blends of monomer casting polyamide 6 (MCPA6) and acrylonitrile‐butadiene‐styrene (ABS) were successfully prepared by in situ polymerization via the application of ε‐caprolactam as a reactive solvent. The morphology and thermal properties of MCPA6/ABS were investigated by means of wide angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), respectively. The domain sizes of the ABS phase in MCPA6/ABS blends were much finer than those in corresponding polyamide 6 (PA6)/ABS blends prepared by simple melt blending. With an increased amount of ABS in MCPA6, the melt enthalpy (ΔHf), the rate of crystallization (Tc) and the degree of crystallinity (Xc(DSC)) of MCPA6 in MCPA6/ABS blends were all decreased. The degree of supercooling (ΔTd) showed a contrary trend. However, the melting temperatures of these blends were almost unchanged. All the results could be attributed to in situ polymerization and the hydrolysis reaction of ABS that occurred during the polymerization process. Furthermore, WAXD results showed that only α‐form crystals existed in the MCPA6/ABS blends, despite the ABS content and heat treatment.

Abstract. Firstly, a novel grafted polypropylene (PP) was prepared by one step free-radical melt grafting method in a single-screw extruder. It was shown that the addition of St to the melt-grafting system as a comonomer could significantly enhance the grafting degree of MMA onto PP and reduced the degradation of PP matrix by means of FTIR and MFR tests, respectively. Then, the extruded multi-monomer grafted PP, as a component, was directly blended with poly(vinyl chloride) (PVC), denoted as gPP/PVC. The corresponding improved compatibility was examined. Due to the addition of gPP the tensile strengths of gPP/PVC blends increased significantly in comparison to pure polypropylene/poly(vinyl chloride) blends (PP/PVC), while the impact strengths remained unchanged. The DSC results also suggested that the compatibility of PP/PVC blends were improved largely.

ABSTRACT:In this article, maleated-grafted ethylene-covinyl acetate (EVA-g-MA) was used as the interfacial modifier for polypropylene/polyamide-6 (PP/PA6) blends, and effects of its concentration on the mechanical properties and the morphology of blends were investigated. It was found that the addition of EVA-g-MA improved the compatibility between PP and PA6 and resulted in a finer dispersion of dispersed PA6 phase. In comparison with uncompatibilized PP/PA6 blend, a significant reduction in the size of dispersed PA6 domain was observed. Toluene-etched micrographs confirmed the formation of interfacial copolymers. Mechanical measurement revealed that the addition of EVAg-MA markedly improved the impact toughness of PP/PA6 blend. Fractograph micrographs revealed that matrix shear yielding began to occur when EVA-g-MA concentration was increased upto 18 wt %.