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A novel mechanism to form binary polymer blends is through phase separation by spinodal decomposition in the unstable region of the phase diagram. The present work investigates the effects of thermally‐induced phase separation by spinodal decomposition on the morphology development of liquid crystalline polymer/polycarbonate blends. Moreover, a thermodynamic binary phase diagram is obtained using a twin‐screw extruder at various processing melt temperatures. Differential scanning calorimetry and scanning electron microscopy were used to study the miscibility of the blends and the resulting morphology. A thermodynamic binary phase diagram exhibiting a lower critical solution temperature was obtained. The droplet size distribution of the blend was also obtained and discussed in light of the Cahn‐Hilliard theory. 相似文献
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通过分析聚碳酸酯的工艺特性,针对特定的厚壁注塑制品,在材料的选择上要考虑熔体流动速率、含水量等;在设备的选择上要考虑螺杆形式、压缩比、长径比等方面;在模具的设计上要考虑采用的浇口形式、大小、脱模斜度、排气、模具预热及冷却等;在注塑工艺上可通过调整料筒温度、注射压力、速度、模温等来设置合理的工艺参数。通过以上一些措施,可以使特定的厚壁制品达到要求。 相似文献
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Interfacial agents as compatibilizers have recently been introduced into polymer blends to improve microstructure and mechanical properties of thermoplastics. In this way, it is possible to prepare a mixture of polymeric materials that can have superior mechanical properties over a wide temperature range. In this study, an incompatible blend of Polycarbonate (PC) and Acrylonitrile Butadiene Styrene (ABS) Copolymer were made compatible by addition of 5, 10, and 20% Styrene–Isopren–Styrene Copolymer (SIS). The mixing operation was conducted using a twin‐screw extruder. The morphology and the compatibility of the mixtures were examined by SEM and DSC techniques. Furthermore, the elastic modulus, tensile and yield strengths, percentage elongation, hardness, melt flow index, Izod impact resistance, heat deflection temperature (HDT), Vicat softening point values of polymer alloys of various ratios were determined. It was found that addition of SIS to the structures decreased the tensile strength, yield strength, elastic modulus, and hardness, whereas it increased Izod impact strength and percentage elongation values. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 559–566, 2006 相似文献
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研究了马来酸酐接枝聚乙烯(PE-g-MAH),核-壳共聚物(甲基丙烯酸甲酯/丁二烯/苯乙烯)共聚物(MBS)和(甲基丙烯酸甲酯/甲基丙烯酸丁酯)共聚物(ACR)对光盘级聚碳酸酯(PC)的增韧作用。结果表明,MBS,ACR能很好地分散在PC中,对PC的增韧效果显著。对PC合金损伤机理的研究表明,核-壳共聚物增韧PC的增韧机理为共聚的粒子的空洞化引发基体的剪切屈服。 相似文献
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Epoxy, prepared through aminomethyl 3,5,5‐trimethylcyclohexylamine hardening of diglycidylether of bisphenol‐A (DGEBA) prepolymer, toughened with polycarbonate (PC) in different proportions, and reinforced with carbon fiber, was investigated by differential scanning calorimetry, tensile and interlaminar shear strength testing, and scanning electron microscopy (SEM). A single glass transition temperature was found in all compositions of the epoxy/PC blend system. The tensile properties of the blend were found to be better than that of the pure epoxy matrix. They increased with PC content up to 10%, beyond which they decreased. The influence of carbon fiber orientation on the mechanical properties of the composites was studied, where the fiber content was kept constant at 68 wt %. Composites with 45° fiber orientation were found to have very weak mechanical properties, and the mechanical properties of the blend matrix composites were found to be better than those of the pure epoxy matrix composites. The fracture and surface morphologies of the composite samples were characterized by SEM. Good bonding was observed between the fiber and matrix for the blend matrix composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3529–3536, 2006 相似文献
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