In this work, rheological properties of poly (lactic acid) (PLA), low density polyethylene (LDPE) polymer blends were investigated in the molten state. The experiments were carried on a capillary rheometer. The effect...In this work, rheological properties of poly (lactic acid) (PLA), low density polyethylene (LDPE) polymer blends were investigated in the molten state. The experiments were carried on a capillary rheometer. The effect of shear stress, temperature and blending ratio on the flow activation energy at a constant shear stress and melt viscosity of the blends are described. The results showed that the PLA/LDPE polymer blends are pseudo plastic in nature, where there viscosity decreases with increasing shear stress. Also it was found the melt viscosity of the blends decreases with increasing PLA content in the blend.展开更多
With the help of differential scanning calorimetry, cone-plate and capillary rheometry andscanning electron microscopy, a research has been conducted on rheological behavior,crystallization and morphology of poly (but...With the help of differential scanning calorimetry, cone-plate and capillary rheometry andscanning electron microscopy, a research has been conducted on rheological behavior,crystallization and morphology of poly (butylene terephthalate) (PBT) blends containing athermotropic LCP. The blend has zero entrance pressure loss, although the LCP has rather largeone. The viscosity curve of the blend lies between those of the LCP and PBT. The crystallizationof PBT is not affected by the presence of the LCP together with no indication oftransesterification between the two ingredients. LCP spheres and ellipsoids with the size of 0. 5--1. 5 μm disperse in PBT matrix uniformly, which is related to the viscosity ratio of the two components.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
热塑性聚乙烯基电缆绝缘材料具有优于交联聚乙烯(cross-linked polyethylene,XLPE)的电气和机械性能,有望成为新一代绿色环保的电缆绝缘材料。在电缆结构设计中,保守的安全绝缘厚度使得电缆的生产成本增加,降低绝缘层的击穿电场强度;并...热塑性聚乙烯基电缆绝缘材料具有优于交联聚乙烯(cross-linked polyethylene,XLPE)的电气和机械性能,有望成为新一代绿色环保的电缆绝缘材料。在电缆结构设计中,保守的安全绝缘厚度使得电缆的生产成本增加,降低绝缘层的击穿电场强度;并且在电缆实际运行过程中,绝缘材料往往工作在70~90℃高温环境下;因此针对新型绝缘材料,温度及厚度对其击穿电场强度的影响研究具有工程实际意义。以线性低密度聚乙烯(linear low density polyethylene,LLDPE)/高密度聚乙烯(high density polyethylene,HDPE)共混绝缘材料为研究对象,进行不同温度下(30、70、90、105℃)及不同厚度下的工频击穿实验,研究温度和厚度对其交流击穿的影响。测试结果表明:相较于XLPE绝缘材料,70L-30H(即LLDPE与HDPE在配比为7∶3的情况下熔融共混得到的绝缘材料)具有较高的工频击穿电场强度,在低于工况温度环境下,其击穿电场强度的温度稳定性较高;然而70L-30H的工频击穿电场强度受厚度影响程度略高,但在相同厚度下其击穿电场强度仍明显高于XLPE。上述研究可为热塑性聚乙烯基电缆绝缘材料研发提供参考。展开更多
文摘In this work, rheological properties of poly (lactic acid) (PLA), low density polyethylene (LDPE) polymer blends were investigated in the molten state. The experiments were carried on a capillary rheometer. The effect of shear stress, temperature and blending ratio on the flow activation energy at a constant shear stress and melt viscosity of the blends are described. The results showed that the PLA/LDPE polymer blends are pseudo plastic in nature, where there viscosity decreases with increasing shear stress. Also it was found the melt viscosity of the blends decreases with increasing PLA content in the blend.
基金Supported by the National Natural Science Foundation of China
文摘With the help of differential scanning calorimetry, cone-plate and capillary rheometry andscanning electron microscopy, a research has been conducted on rheological behavior,crystallization and morphology of poly (butylene terephthalate) (PBT) blends containing athermotropic LCP. The blend has zero entrance pressure loss, although the LCP has rather largeone. The viscosity curve of the blend lies between those of the LCP and PBT. The crystallizationof PBT is not affected by the presence of the LCP together with no indication oftransesterification between the two ingredients. LCP spheres and ellipsoids with the size of 0. 5--1. 5 μm disperse in PBT matrix uniformly, which is related to the viscosity ratio of the two components.
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.
文摘热塑性聚乙烯基电缆绝缘材料具有优于交联聚乙烯(cross-linked polyethylene,XLPE)的电气和机械性能,有望成为新一代绿色环保的电缆绝缘材料。在电缆结构设计中,保守的安全绝缘厚度使得电缆的生产成本增加,降低绝缘层的击穿电场强度;并且在电缆实际运行过程中,绝缘材料往往工作在70~90℃高温环境下;因此针对新型绝缘材料,温度及厚度对其击穿电场强度的影响研究具有工程实际意义。以线性低密度聚乙烯(linear low density polyethylene,LLDPE)/高密度聚乙烯(high density polyethylene,HDPE)共混绝缘材料为研究对象,进行不同温度下(30、70、90、105℃)及不同厚度下的工频击穿实验,研究温度和厚度对其交流击穿的影响。测试结果表明:相较于XLPE绝缘材料,70L-30H(即LLDPE与HDPE在配比为7∶3的情况下熔融共混得到的绝缘材料)具有较高的工频击穿电场强度,在低于工况温度环境下,其击穿电场强度的温度稳定性较高;然而70L-30H的工频击穿电场强度受厚度影响程度略高,但在相同厚度下其击穿电场强度仍明显高于XLPE。上述研究可为热塑性聚乙烯基电缆绝缘材料研发提供参考。
