填充聚合物的流变行为

随着大量新型高分子材料的出现,了解高分子加工过程中的流变行为及规律,对于实际生产应用具有重要理论指导意义。分别讨论了炭黑填充聚合物、无机物质填充聚合物、纤维填充聚合物等填充聚合物体系的流变行为,初步探讨了影响填充聚合物流变性能的因素,并对其流变特性和粘弹性质作了简要概括。     

填充聚合物的流变行为探讨

对炭黑、无机物质、纤维填充聚合物的流变行为分别进行了讨论。初步探讨了影响填充聚合物流变性能的因素,并概括了其流变特性和粘弹性质。     

无机粒子填充聚合物的流变行为

研究了无机粒子填充聚合物的流变行为，探讨了无机粒子体积分数、无机粒子和聚合物组分特性、无机粒子与聚合物的界面特性和相互作用、以及加工条件对无机粒子填充聚合物的流变行为的影响。研究表明，一般情况下无机粒子填充聚合物的黏度随着填充聚合物体积分数的增加而增大；粒子性质、聚合物组分特性都会对流变性能产生影响，目前只能通过实验进行优选；无机纳米粒子填充聚合物有不同于普通粒子填充的反常现象，如果纳米粒子体积分数控制在一定范围内，填充聚合物的黏度可能出现随填充粒子体积分数增大而下降的趋势；表面活性剂、偶联剂等可以使无机粒子填充聚合物的流动性能得到显著改善；高速混合、增大剪切速率及升高温度都可以使无机粒子填充聚合物有更好的流变性能。     

高填充性聚合物/纳米粒子复合材料的流变行为研究进展

介绍了纳米粒子的含量、尺寸、形状、表面处理、分散性和聚合物熔体等对聚合物/纳米粒子复合材料流变行为的影响,概述了近些年来高填充性聚合物/纳米粒子复合材料的流变行为的研究进展,并对高填充性聚合物/纳米粒子复合材料的黏弹机理进行了总结。     

粘土或纳米碳酸钙填充聚合物的结晶性能和流变行为研究

总结了粘土、纳米碳酸钙填充聚合物的结晶性能和流变行为，阐述了无机纳米填料对聚合物复合材料结晶性能和流变行为的影响，同时论述了结晶性能和流变行为与纳米复合材料力学性能及加工性能的关系。结果表明，粘土和纳米碳酸钙对结晶聚合物均有异相成核剂的作用，在基本保持聚合物强度的同时，明显改善复合材料的韧性，同时保持材料原有的加工性能。     

玻璃微珠填充改性聚合物研究进展

玻璃微珠作为一种新型刚性粒子,除了对聚合物有增强增韧作用,在许多方面都已引起聚合物改性工作者的关注。本文从玻璃微珠对聚合物的增韧效果、玻璃微珠填充聚合物的界面、拉伸性能、动态力学性能、流变性能、压缩性能以及其他性能等方面综述了近年来玻璃微珠填充改性聚合物的最新研究进展。     

高填充聚乙烯体系中碳酸钙对模头析出的影响

在无机填料高填充的聚合物体系中,除了流动过程中聚合物熔体的粘弹性行为外,填料也是引起析出的一个重要因素。本工作研究了碳酸钙高填充聚乙烯的模头析出现象。通过析出实验、流变性能、扫描电镜图像及热性能等测试结果,分析填充聚合物的析出物成分和填料的填充量、粒径及其分布以及表面处理等因素对混合物模头析出的影响。     

聚乙烯改性材料流变行为研究进展

对无机粒子、弹性体和其他类型的聚合物填充改性聚乙烯的流变行为分别进行了讨论，探讨了影响各个体系的流变性能的因素及产生这种流变行为的机理，并总结了改性体系的流变行为的较典型的一些规律。     

填充剂分散作用的研究

尽管填充剂在溶体聚合物中的分散性能通常借助各种助剂来改善,但尚无用来表征助剂对流变性能影响的简单方法。加入填充剂可改变聚合物的流变性能,这种影响通常压低剪切速率下更大。这是由于填充剂颗粒的凝聚作用所致。据发现,在小应变幅度下的动态测定法预期对凝聚程度敏感。然而,简单的毛细管粘度法对填充剂的扩散细节并不敏感。本文将选定这两种主要方法一小应变幅度试验法和毛细管粘度计法进行比较的方法以表征矿物填充热塑性塑料的流变行为。本实验是以含有不同表面处理剂的白云灰质碳酸钙填充的聚丙烯作为研究对象。     

PET/蒙脱土纳米复合材料的流变性能

采用毛细管流变仪的方法，研究具有反应活性的有机蒙脱土与聚对苯二甲酸乙二酯通过原位聚合和熔融共混所得的2种插层复合材料的流变行为。结果表明，2种插层方法制备的纳米复合材料在熔融流变性能方面具有较大的差异，熔融共泥时更表现出无机填充聚合物体系的普通特征。熔融插层复合材料在低浓度复合时会出现高浓度大颗粒粒子填充聚合物体系类固体行为的屈服现象。     

Rheological behavior of polymer melts with natural fibers

Flow behavior of polymer liquids filled with short fibers (particulate fillers) was theoretically analyzed from the point of view of the free volume theory. Assuming that the filler addition changes the occupied volume, while the temperature variations cause mainly the free volume changes, a general expression describing the viscosity of the system as a function of the filter content, temperature variations, and rheological properties of the pure polymer liquid was derived. If the viscosity curve of the unfilled polymer is described by the Carreau equation, the corresponding viscosity curve of the filled polymer is also represented by an equation of Carreau type. However, this equation has other values of Newtonian viscosity and the power exponent in comparison with the initial equation. Both parameters depend on the filler content and temperature. The derived equation predicts a viscosity rise and a stronger non‐Newtonian behavior of the system with increasing filler content. The temperature rise exerts an opposite effect on the rheological behavior. The theoretical predictions are in good accordance with viscosity measurements for low‐density polyethylene and polystyrene melts filled with short cotton, flax, and hemp fibers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1401–1409, 2005     

填充型导电高分子复合材料的逾渗理论进展

总结了粒子填充型导电体系逾渗网络的形成及逾渗理论概况，以热力学和动力学的观点对导电粒子种类、形状、浓度、分布和分散、基体树脂的种类、粒子与基体树脂的相互作用、加工条件等影响逾渗的重要因素作了系统的分析，阐明了体系的导电性、微观形貌、流变性能和物理性能的相互关系。对低逾渗值填充聚合物尤其是炭黑复合材料的成型与加工提供了理论指导。     

Rheological behavior of neat and carbon fiber-reinforced poly(ether ketone ketone) for extrusion deposition additive manufacturing

To develop new materials for extrusion additive manufacturing (AM) systems, a fundamental understanding of rheological properties is essential to correlate the effect of processing on material structure and its properties. In this work, the rheological properties of five different grades of neat and carbon fiber (CF)-reinforced poly(ether ketone ketone) are reported. Rheological properties are essential to understand the effect of reinforcing fibers and AM process parameters such as time, temperature, environment, and shear rate on flow behavior during processing. Small-amplitude oscillatory shear tests and steady shear tests indicated neat grades to exhibit less increase in viscosity over time when processed in air than the CF-filled grades. The filled grades showed greater shear thinning and lower sensitivity to temperature. Overall, this rheological analysis provides a broad framework for determining appropriate processing conditions for extrusion deposition AM of such high-temperature polymer systems.     

Study of the Role of Silane-treated Filler on the Compatibility of Polypropylene/Polystyrene Blends at Different Ratios

A systematic study of the effect of the filler on the immiscible blend properties is presented as a function of the blend composition. As a representative of semicrystalline polymer/amorphous polymer blends, a polypropylene/polystyrene system was chosen. The presence of filler in the blends has induced significant changes in the rheological properties. This behavior is a function not only of filler surface treatment but also of blend composition. Solid state dynamic mechanical analysis is performed and the relaxation behavior is correlated with the morphology of the blends. The increase in tensile strength of the blends filled with surface-treated glass beads is related to the enhancement of the adhesion and polymer/polymer interactions.     

晶须状碳酸钙填充聚合物材料性能的研究

研究了晶须状碳酸钙的填充量及表面处理状况对填充ＰＶＣ材料和ＰＰ材料性能的影响。力学性能和流变性能的测试结果表明，碳酸钙晶须作为填充材料，在相同的填充量下加工 交小、拉伸强度和冲击强度较高，对晶须进行适当的表面处理后，体系的性能可以得到进一步提高，这是因为晶须具有特殊的针状外形，在加工应力的作用下可以迅速地在聚合物熔体中定向排列，对体系起到良好的增强和增韧作用。     

Morphology and finite strain rheologyof NBR/TPU blends

Due to orientational and dispersional interactions between molecules in polar polymer blends, such as NBR/TPU, secondary molecular networks are formed, which, despite their weakness, essentially affect rheological properties of the blends. Being highly susceptible to strain and temperature changes, the secondary networks under such conditions undergo breakdown, causing changes in blends' rheological characteristics. Particularly suitable method for tracking such network breakdown is by measuring the blends' dynamic mechanical functions at different strains and temperatures. For elucidation of these measurements a model is chosen, analysing a secondary network breakdown by statistical mechanics, whose final result is strain, temperature and compositional dependence of the blends' dynamic mechanical functions. Along with the measurements', the chosen model, originally devised to study rheological properties of carbon black filled rubbers, also provides means for quantitative characterization of secondary networks in polar polymeric systems.