Polypropylene（PP）/ethylene-octene copolymer（POE） blends were prepared with a twin-screw extruder.Their dynamic mechanical behavior were systematically investigated.The results show that PP/POE blends are heterogen...Polypropylene（PP）/ethylene-octene copolymer（POE） blends were prepared with a twin-screw extruder.Their dynamic mechanical behavior were systematically investigated.The results show that PP/POE blends are heterogeneities with a partial compatible two-phase structure,the glass transition temperature of PP phases in the blends tends to shift towards high temperature with increasing the POE content,and the glass transition temperature of POE phases shifts towards the low temperature with increasing the PP content.The Kerner＇s dispersed phase model and co-continuous phase model can reasonably predict the visco-elasticity of PP/POE blends with different compositions.Additionally,the morphological structure of the blends can be estimated via comparing the predicted DMA behavior with the experimental data.展开更多
A polymer blends containing thermoplastic polyurethane（TPU） and poly（lactic acid）（PLA） as a biomedical material were prepared by a process of modifying thermally induced phase separation（MTIPS） and melt blendi...A polymer blends containing thermoplastic polyurethane（TPU） and poly（lactic acid）（PLA） as a biomedical material were prepared by a process of modifying thermally induced phase separation（MTIPS） and melt blending.The influences of composition,shear frequency,and temperature on the rheological behaviors of the blends were investigated by small amplitude oscillatory shear rheology.The results revealed that the addition of TPU into PLA significantly decreased the non-Newtonian index of the blends,and increased the sensitivity of the blends on shear rate,suggesting that optimization of the shear rate and temperature could improve the flowability of the blend melts in the extrusion process.In addition,the results of SEM images revealed that TPU distributed well into PLA matrix and showed good compatibility between the TPU and PLA,which made the blends with good toughness.The primary cytocompatibility of the blends was evaluated using C2C12 cells.The results suggested that the TPU/PLA blends did not affect cell growth,showing no cytotoxicity.In short,the TPU/PLA blends with excellent toughness had potential application as biomedical devices.展开更多
A new Nylon 11（PA11）/polyethylene-octene（POE） blends compatibilized by maleic anhydride grafted mixture polyethyleneocten（POE-g-MAH） was prepared through melt blending method.The isothermal crystallization kinet...A new Nylon 11（PA11）/polyethylene-octene（POE） blends compatibilized by maleic anhydride grafted mixture polyethyleneocten（POE-g-MAH） was prepared through melt blending method.The isothermal crystallization kinetics and melting behaviors of PA11/POE blends were investigated in detail by differential scanning calorimetry（DSC） and polarized optical microscope.The n values of PA11 blending with POE or POE-g-MAH are almost similar with pure PA11,which indicates that the effect of POE and POE-g-MAH on nucleation and growth of PA11 crystal is slight.The overall crystallization rate of PA11/POE blends are higher than ones of pure PA11 at the same crystallization temperatures,but they decrease significantly when POE-g-MAH is added into PA11/POE blends.DSC heating curves of both PA11 and its blends exhibit two melting peaks,but the two melting peak become weaker when POE-g-MAH is add into PA11/POE blend systems.And the spherulite size is reduced significantly by the addition of POE-g-MAH compared with pure PA11 and PA11/POE blends.展开更多
A method to quantify crazing deformations by tensile tests for polystyrene （PS） and polyolefin elastomer （POE） blends was investigated. The toughness of PS/POE blends, reflected by the Charpy impact strength, incr...A method to quantify crazing deformations by tensile tests for polystyrene （PS） and polyolefin elastomer （POE） blends was investigated. The toughness of PS/POE blends, reflected by the Charpy impact strength, increased with the content of POE. SEM micrographs showed the poor compatibility between PS and POE. In simple tensile tests, it is very easy to achieve the ratio of crazing deformation, i.e. K by measuring the size changes of samples. The K values decreased with increasing the content of POE, and the deformations of PS/POE blends were dominated by crazing. The plots of the change of volume （△V） against longitudinal variation （△I） showed a linear relationship, and the slope of lines decreased with the content of POE. Measuring samples at the tensile velocities of 5 mm/min, 50 mm/min, and 500 mm/min respectively, the K values kept unchanged for each PS/POE blends.展开更多
基金Supported by the National Natural Science Foundation of China(No.20490220)Open Fund of State Key Laboratory of Plastic Forming Simulation and Die & Mould Technology,China(No.05-10)+1 种基金Open Fund of Hubei Key Laboratory of Materials Chemistry and Service FailureProgram for New Century Excellent Talents in Universities of China(No.NCET-05-0640)
文摘Polypropylene（PP）/ethylene-octene copolymer（POE） blends were prepared with a twin-screw extruder.Their dynamic mechanical behavior were systematically investigated.The results show that PP/POE blends are heterogeneities with a partial compatible two-phase structure,the glass transition temperature of PP phases in the blends tends to shift towards high temperature with increasing the POE content,and the glass transition temperature of POE phases shifts towards the low temperature with increasing the PP content.The Kerner＇s dispersed phase model and co-continuous phase model can reasonably predict the visco-elasticity of PP/POE blends with different compositions.Additionally,the morphological structure of the blends can be estimated via comparing the predicted DMA behavior with the experimental data.
基金Funded by the Major State Basic Research Development Program of China(973 Program)(No.2012CB933600)the National Natural Science Foundation of China(Nos.81271705 and 83171383)the Major Program of Natural Science Foundation of Shanghai,China(No.12JC1416302)
文摘A polymer blends containing thermoplastic polyurethane（TPU） and poly（lactic acid）（PLA） as a biomedical material were prepared by a process of modifying thermally induced phase separation（MTIPS） and melt blending.The influences of composition,shear frequency,and temperature on the rheological behaviors of the blends were investigated by small amplitude oscillatory shear rheology.The results revealed that the addition of TPU into PLA significantly decreased the non-Newtonian index of the blends,and increased the sensitivity of the blends on shear rate,suggesting that optimization of the shear rate and temperature could improve the flowability of the blend melts in the extrusion process.In addition,the results of SEM images revealed that TPU distributed well into PLA matrix and showed good compatibility between the TPU and PLA,which made the blends with good toughness.The primary cytocompatibility of the blends was evaluated using C2C12 cells.The results suggested that the TPU/PLA blends did not affect cell growth,showing no cytotoxicity.In short,the TPU/PLA blends with excellent toughness had potential application as biomedical devices.
文摘A new Nylon 11（PA11）/polyethylene-octene（POE） blends compatibilized by maleic anhydride grafted mixture polyethyleneocten（POE-g-MAH） was prepared through melt blending method.The isothermal crystallization kinetics and melting behaviors of PA11/POE blends were investigated in detail by differential scanning calorimetry（DSC） and polarized optical microscope.The n values of PA11 blending with POE or POE-g-MAH are almost similar with pure PA11,which indicates that the effect of POE and POE-g-MAH on nucleation and growth of PA11 crystal is slight.The overall crystallization rate of PA11/POE blends are higher than ones of pure PA11 at the same crystallization temperatures,but they decrease significantly when POE-g-MAH is added into PA11/POE blends.DSC heating curves of both PA11 and its blends exhibit two melting peaks,but the two melting peak become weaker when POE-g-MAH is add into PA11/POE blend systems.And the spherulite size is reduced significantly by the addition of POE-g-MAH compared with pure PA11 and PA11/POE blends.
文摘A method to quantify crazing deformations by tensile tests for polystyrene （PS） and polyolefin elastomer （POE） blends was investigated. The toughness of PS/POE blends, reflected by the Charpy impact strength, increased with the content of POE. SEM micrographs showed the poor compatibility between PS and POE. In simple tensile tests, it is very easy to achieve the ratio of crazing deformation, i.e. K by measuring the size changes of samples. The K values decreased with increasing the content of POE, and the deformations of PS/POE blends were dominated by crazing. The plots of the change of volume （△V） against longitudinal variation （△I） showed a linear relationship, and the slope of lines decreased with the content of POE. Measuring samples at the tensile velocities of 5 mm/min, 50 mm/min, and 500 mm/min respectively, the K values kept unchanged for each PS/POE blends.
