共查询到19条相似文献,搜索用时 156 毫秒
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以钛酸酯偶联剂(NDZ-105)改性的高岭土为填料、马来酸酐接枝的聚丙烯(PP-g-MAH)为相容剂,与聚丙烯(PP)熔融共混制备复合材料,测定了复合材料的力学性能,并通过X射线衍射(XRD)、红外光谱(Fr-IR)、热失重分析(TG)、扫描电镜(SEM)等手段研究其结构.结果表明,NDZ-105分子包覆到高岭土颗粒表面,有效改善了高岭土与PP基体的相容性;改性高岭土在PP基体中起到异相成核作用,并诱导PP基体产生β晶型;与纯PP及PP/未改性高岭土复合材料相比,PP/改性高岭土复合材料的拉伸强度、冲击强度、屈服强度、弹性模量、维卡软化温度及外推起始失重温度均明显提高,分别增加了7.6%、31%、21%、89.3%、8.4℃及97℃. 相似文献
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通过差示扫描量热(DSC)仪分析了己二酸(AA)和无水硫酸钙晶须(ACSW)复配改性聚丙烯(PP)的等温结晶行为,用偏光显微镜(PLM)观察了AA/ACSW复配改性PP的晶体形貌。DSC分析结果表明,随着结晶温度升高,半结晶时间和最大结晶时间增加,半结晶速率降低;与纯PP相比,ACSW和AA/ACSW复合改性都能使PP的结晶时间降低,结晶效率增加,说明ACSW和AA/ACSW对PP具有异相成核作用,并且AA/ACSW复合改性PP对提高PP的结晶性能有更好的效果,此外ACSW改性PP的等温结晶活化能最低。对改性PP的PLM的观察说明ACSW对PP具有异相成核作用,而AA/ACSW对PP的β晶成核具有协同促进作用。 相似文献
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滑石粉、碳酸钙填充聚丙烯复合材料等温结晶行为的对比研究 总被引:3,自引:0,他引:3
邹燕;纪彬彬;温变英 《中国塑料》2010,24(2):26-29
用熔融共混法分别制备了聚丙烯(PP)/滑石粉、PP/碳酸钙(CaCO3)复合材料,用差示扫描量热法(DSC)考察了PP及其复合材料的等温结晶过程,并用Avrami方程对纯PP及PP/滑石粉、PP/CaCO3复合材料的等温结晶动力学行为进行了分析。结果表明,PP、PP/滑石粉及PP/CaCO3复合材料的Avrami指数均小于2.3,存在均相成核和异相成核双重成核机理,且其结晶速率常数和结晶速率均随着结晶温度的升高而减小;在该体系中,滑石粉对基体PP有明显的异相成核作用,使PP的结晶速率加快、结晶时间缩短;而CaCO3则没有明显的异相成核作用。 相似文献
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通过双螺杆挤出机熔融共混制备了聚丙烯(PP)/凹凸棒土(ATP)复合材料样品,分别采用偏光显微镜和差示扫描量热仪对其结晶行为进行了研究。研究表明,复合材料样品的偏光显微镜照片呈现球晶所特有的十字消光现象,球晶尺寸与纯PP球晶的尺寸相比有所减小。非等温结晶测试结果表明,复合材料样品的结晶温度随着ATP含量的增加向高温方向移动,而且半结晶期缩短,PP/ATP复合材料的总体结晶速率增加;ATP的加入改变了PP成核的机制,起到了异相成核的作用。随着降温速率的增大,PP及PP/ATP(95/5)复合材料的结晶起始温度和结晶峰值温度均向低温方向移动,半结晶期变短。 相似文献
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以聚丙烯(PP)、聚酯(PET)纤维为主要原料,马来酸酐接枝PP(PP-g-MA)为相容剂,经熔融共混、粉碎、注塑加工成样条后进行表征,并研究了其性能。结果表明:PET纤维对PP具有异相成核作用,主要诱导PP形成α晶,可提高PP结晶温度并降低球晶尺寸;PET纤维可显著提高PP的拉伸强度和弹性模量,但会降低其冲击强度;加入相容剂PP-g-MA对PP/PET纤维共混物的结晶性能基本无影响,但对其力学性能影响显著,与未增容的PP/PET纤维共混物相比,经PP-g-MA增容后,共混物的拉伸强度、冲击强度、弹性模量均得到显著提升。 相似文献
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合成了YB超分散剂并制备talc/PP复合材料。采用红外光谱(FT-IR)、差示扫描(DSC)、X衍射(XRD)和扫描电镜(SEM)等方法研究了复合材料的结晶行为和微观结构。结果表明:改性后的talc表面连接了新的有机基团;talc的加入具有异相成核作用,提高了PP结晶温度,但无晶型转变,当talc用量超过30%,异相成核作用减弱;超分散剂与talc存在异相成核协同作用,进一步提高结晶温度,并且对β晶型具有诱导效应,YB超分散剂加入,使部分α晶型向β晶型转变;同时使复合材料的冲击断面从脆性断裂转变为强韧性断裂。 相似文献
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Hai Huang Bing Han Lei Wang Ning Miao Hong Mo Ning‐Lin Zhou Zhen‐Mao Ma Jun Zhang Jian Shen 《应用聚合物科学杂志》2011,119(3):1516-1527
The subject of this study was the crystallization behavior and thermal properties of polypropylene (PP)/maleic anhydride (MAH) modified nano calcium carbonate (nano‐CaCO3) composites. In this study, 5 wt % nano‐CaCO3 modified with different contents of MAH was filled into a PP matrix. X‐ray diffraction and differential scanning calorimetry were used to characterize the crystal morphology and crystallization kinetics of a series of composites. The results demonstrate that the nano‐CaCO3 modified with MAH had an important effect on the thermal and morphological properties of the nanocomposites. The Avrami exponent of the pure PP was an integer, but those of the composites were not integers, but the crystallization rate constant decreased as the content of MAH in the nano‐CaCO3 filler increased in isothermal crystallization. In nonisothermal crystallization, the kinetic parameter F(T) and the degree of crystallinity of pure PP were compared with those of the PP composites filled with nano‐CaCO3. We suggest that heterogeneous nucleation existed in the PP composites and that the transformation and retention of the β‐form crystal into the α‐form crystal took place in the composite system and the β‐form crystal had a higher nucleation rate and growth process than the α‐form crystal in the PP composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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通过采用PEG10000改性沸石,并与聚丙烯(PP)进行共混制备了聚丙烯/沸石复合材料。对复合材料进行热性能、结晶形态及微观形态测试分析。结果表明,沸石的引入使PP产生了异相成核结晶,结晶度提高;沸石质量分数为3%时,复合材料体系结晶较为完善;而随着沸石用量进一步提高,复合材料的结晶尺寸快速下降,呈现碎晶状。采用PEG10000对沸石进行有机化改性抑制了沸石在PP中团聚,实现了较好的分散。 相似文献
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The crystallization and melting behavior of isotactic polypropylene (iPP) and polypropylene copolymer (co‐PP) containing silicon dioxide (SiO2) were investigated by differential scanning calorimeter (DSC). SiO2 had a heterogenous nucleating effect on iPP, leading to a moderate increase in the crystallization temperature and a decrease in the half crystallization time. However, SiO2 decreased the crystallization temperature and prolonged the half crystallization time of co‐PP. A modified Avrami theory was successfully used to well describe the early stages of nonisothermal crystallization of iPP, co‐PP, and their composites. SiO2 exhibited high nucleation activity for iPP, but showed little nucleation activity for co‐PP and even restrained nucleation. The iPP/SiO2 composite had higher activation energy of crystal growth than iPP, indicating the difficulty of crystal growth of the composite. The co‐PP/SiO2 composite had lower activation energy than co‐PP, indicating the ease of crystal growth of the composite. Crystallization rates of iPP, co‐PP, and their composites depended on the nucleation. Because of its high rate of nucleation, the iPP/SiO2 composite had higher crystallization rate than iPP. Because of its low rate of nucleation, the co‐PP/SiO2 composite had lower crystallization rate than co‐PP. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1889–1898, 2006 相似文献
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The influence of lignin (L) on the thermal properties and kinetics of crystallization of isotactic polypropylene (PP) is reported in this article. PP blends containing 5 and 15 wt % of L were prepared by mixing the components in a screw mixer. An increase of the thermal degradation temperature of the blends was observed as a function of L content. The crystallization and thermal behavior of the pure PP and of the PP/L blends were analyzed by differential scanning calorimetry (DSC). Isothermal crystallization kinetics were described by means of the Avrami equation, which suggests a three‐dimensional growth of crystalline units, developed by heterogeneous nucleation. The isothermal growth rate of PP spherulites was studied using a polarizing optical microscope. The enhancement of PP crystallization rate for the PP/L blends was observed and ascribed to the nucleating action of lignin particles. Non‐isothermal crystallization kinetics were applied, according to the results elaborated by Ziabicki and the method modified by Jeziorny. The kinetic crystallizability of the PP is not influenced by the L present in the blend. In the presence of L, PP can simultaneously crystallize in both the α and β crystalline forms, and the ratio between the α and β forms was determined by X‐ray diffraction analysis. Two melting peaks relative to the two crystalline form of PP were observed for the PP/L blends, for all isothermal crystallization temperatures investigated by means of DSC. The equilibrium melting temperature for α‐form of pure PP was obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1435–1442, 2004 相似文献
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Tomlal Jose E. Aju Joseph Mikael Skrifvars Sabu Thomas Kuruvilla Joseph 《Polymer Composites》2010,31(8):1487-1494
Techniques like thermogravimetric analysis, differential scanning calorimetry, and polarized optical microscopy were used to study the thermal and crystallization behavior of cotton‐polypropylene (PP) commingled composite system. Thermal analysis was used to understand the structure‐property relationship and also to quantify the amount of moisture and volatiles, which causes the deterioration of the composite performance. Thermal stability of the composite was found be intermediate between that of PP and cotton fibers. Presence of treated reinforcements had increased the crystallinity of PP. Also, fibers act as heterogeneous nucleants and favor the early crystallization of PP in the composites. The crystallization and onset crystallization temperature values were increased by the presence of cotton fibers. The theories of heterogeneous nucleation and crystal growth kinetics were used to explain the growth of transcrystalline layer (TCL) of PP on cotton fibers. The interfacial free energy difference for nucleation of PP on fiber was found to be smaller compared with that in the bulk PP. This favors the formation and growth of TCL. The thickness of TCL and radius of the spherulites increase with the increase in the crystallization temperature. Fiber surface roughness and thermal stresses facilitate the growth of transcrystallinity on cotton fiber. POLYM. COMPOS., 31:1487–1494, 2010. © 2009 Society of Plastics Engineers 相似文献
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