Papers by Author: Kun Yan Wang

Abstract: Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/functionalized graphene blends were prepared by solution blend method. The structure, thermal properties, thermal degradation and crystalline morphology were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetry (TG), and polarizing optical microscopy (POM) analyses. Experimental results indicated that FGO increase the intensity of diffraction peak. Small-sized PHBV spherulites were formed. FGO affects the crystallization behavior of PHBV as heterogeneous nucleation agent. FGO acts as an effective thermal barrier due to its large aspect ratio and thereby hinders the degradtion of PHBV.

Abstract: Polypropylene (PP)/ethylene-vinyl acetate (EVA) blends were prepared using a twin-screw extruder by melt blending method. The influences of the EVA contents in PP/EVA blends on crystallization behavior and mechanical properties were investigated by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). XRD results show that the EVA not change the crystal structure in the blends but only decrease the intensity of the diffraction peak. DSC results showed that the melting point and crystallization point decreased when EVA added to the blend. The tensile properties of PP/EVA blend become much better.

Abstract: Polypropylene (PP)/Maleic anhydride grafted poly (ethylene-octene) (POEg) were prepared by melt blending method. The crystallization behavior and crystal morphology were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and polarzing optical microscope (POM). Differential scanning colorimetry (DSC) experiments showed that the melting point and crystallization point decreased when POEg added to the blend. XRD results show that the POEg not change the crystal structure in the blends but only decrease the intensity of the diffraction peak. The spherulitic structure could also observed when added POEg to the matix of PP, but the shape of the spherulites distorted.

Abstract: Poly (trimethylene terephthalate) (PTT)/acrylonitrile-butadiene-styrene (ABS) blends have been prepared in composition with various ratios using the twin screw extruder approach. Their morphologies and crystallization behavior were investigated. Typical sea-island morphologies were observed by scanning electron microscopy. The partical size of ABS increased as the content of ABS increasing. Differential scanning colorimetry (DSC) experiments showed that the melting point of pure PTT and their blends was almost constant. The presence of the ABS increased the crystallinity of the matrix in PTT/ABS blends with ABS content less than 30wt%.

Abstract: Poly (3-hydroxybutyrate-co-3-hydroxyvalerate)/CaCO₃ blends were prepared by solution blend method. The effect of CaCO₃ on the thermal and crystalline morphology properties was studied by differential scanning calorimetry (DSC), thermogravimetry (TG) and polarizing optical microscopy (POM) analyses. DSC showed the CaCO₃ affected the crystallization behavior of PHBV as heterogeneous nucleation agent. TG results indicated better processability of the blends with 3wt% CaCO₃ than that of pure PHBV. Integrated Maltese crossed spherulitic morphologies were revealed for both pure PHBV and PHBV/CaCO₃ blend. While small-sized PHBV spherulites were formed when CaCO₃ added to PHBV.

Abstract: Polypropylene/organoclay modified by dodecanol phase change material were prepared by melt blending method. The thermal stability and crystallization behavior was studied by thermogravimetry (TG), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). TG results indicated the window of processing of PP could be improved by adding small amount organoclay modified by dodecanol to the blend. DSC showed the organoclay modified by dodecanol affected the crystallization behavior of PP as heterogeneous nucleation agent. XRD results show that the organoclay modified by dodecanol does not change the crystal structure in the blends but only decrease the intensity of the diffraction peak.

Abstract: Several blends of poly (trimethylene terephthalate) and the classical mesogen jacketed liquid crystal polymer poly{2,5-bis[(4-butoxyphenyl)oxycarbonyl]-styrenes}(PBPCS) have been prepared with different compositions. The rheological and crystallization properties of the prepared blends have been investigated. The effect of the PBPCS amount on the complex viscosity was quit prominent at low frequency, and decreased with increasing frequency. Differential scanning colorimetry(DSC) experiments showed that adding small content of PBPCS (0.5wt%), the melting point of was slightly higher than that of pure PTT and The crystallinity of PTT incresased.

Abstract: Poly (trimethylene terephthalate)/polybutadiene grafted polymetyl methacrylate (PB-g-PMMA, MB) blends were prepared by melt processing with and without diglycidyl ether of bisphenol-A (DGEBA) epoxy resin as a reactive compatibilizer. The rheological and crystallization properties of the prepared blends have been investigated. The complex viscosity of PTT/MB blend increased in the presence of DGEBA at low frequency range. Differential scanning colorimetry(DSC) experiments showed that the melting point of pure PTT and their blends was almost constant. Crystallization points decreased when 1wt% DGEBA added to the blend.

Abstract: The blends of poly(trimethylene terephthalate) (PTT) with ethylene-propylene-diene copolymer grafted with maleic anhydride (EPDM-g-MA) and organoclay(OMMT) were prepared by melt blending.The composites were characterized by dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). The results suggest that the PTT is immiscible with EPDM-g-MA when OMMT was added to the blends. Strorage modulus of the PTT/EPDM-g-MA/OMMT are higher than those of pure PTT. The melting point of pure PTT and blends was almost constant. The crystallinity of the blends with OMMT were higher than that of pure PTT.

Abstract: Poly(trimethylene terephthalate) (PTT), and three different rubbers(maleated styrene-butylene-co-ethylene-styrene copolymer (SEBS-g-MA), ethylene-propylene-diene copolymer grafted with maleic anhydride (EPDM-g-MA) and maleic anhydride grafted poly (ethylene-octene) (POE-g-MA)) were mixed in the melt state. Their rheological properties and spherulite morphology were investigated. Rheological properties shows torque decreases with the time increasing for all blends. PTT/SEBS-g-MA blend have better processability than PTT/EPDM-g-MA and PTT/ POE-g-MA blend. Polarizing optical microscopy (POM) experiments showed that the introduction of rubber chain greatly affects the size of the PTT spherulites. Small-sized PTT spherulites were formed when rubber added to PTT.