Study On Properties Of PB-1/PB-PP/PP Extruded Blends

Iso-polybutene-1 (PB-1) has good properties such as thermal creep esistance, low temperature fluidity resistance, environmental stress crack resistance, mechanical strength and high toughness, therefore, it is honored as the "golden plastic". In this paper, PB-1 was blended with polypropylene (PP) to improve the performance of PB-1 and reduce it’s costs. Considering the incompatibility of PB-1 and PP, PB-1/PB-PP/PP blends were prepared by melting blending PB-1 and PP with the ratio of 60/40 through extruder, using PB-PP as compatibilizer which synthesised by melting grafting and crosslinking polymerization of PB and PP. The crystallization behavior of the blends were studied via polarized optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction(XRD); the mechanical properties were studied via mechanical testing machines and mechanical analyzer (DMA); the rheological behavior were studied via dynamic rheometer and capillary rheometer. In addition, we studied the thermally stimulated shape memory behavior of the blends.The results showed that when the preparation temperature of the compatibilizer is 175 ℃,mixing time is 7min and BPO content is 1.5wt%, PB-PP exhibited the best compatibilization efficiency to PB-1/PP blends. After adding the compatibilizer in the blends, the size of spherulites of PB-1 and PP decreased; two components retained their peaks without new crystal; the crystallinity of PB-1/PB-PP/PP blends decreased with the compatibilizer adding; the tesile properties of the blends were the highest when the content of compatibilizer was 2phr; the E" and E1 of ternary blends alloy were the highest when the content of compatibilizer was 2phr on certain temperature. In addition, when the content of compatibilizer is 2phr, the Cole-Cole curves develop to almost semicircular shape, so the compatibility of PB-1 and PP got improved; when the PB-1/PB-PP/PP blend ratio is 60/2/40, the stretch ratio is 60%,the tensile speed is 35mm/min, and the recovery temperature is 150℃, PB-1/PB-PP/PP blends shows the optimal shape memory properties.