无机刚性粒子增韧增强PP研究进展

综述了近些年来无机刚性粒子增韧聚丙烯（PP）的结构设计、刚性粒子粒径及其分布、改性剂种类及用量对增韧增强效果的影响以及无机刚性粒子增韧PP的机理。大量的研究表明，在刚性粒子增韧PP中，弹性体包覆刚性粒子的壳一核结构设计具有优异的增韧效果。在定量分析PP增韧机理方面，介绍了脆韧转变分析中界面黏结判据和粒间距判据，以及有限元方法在此领域的应用，刚性粒子增韧机理主要为界面脱黏到空洞／银纹化损伤和空洞／剪切屈服损伤的转变。此外还介绍了目前刚性粒子与橡胶混杂增韧PP的研究进展。     

刚性粒子增韧机理研究进展

本文综述了刚性有机粒子增韧、刚性无机粒子增韧、纳米粒子增韧和刚性粒子一弹性体混合增韧的增韧机理。分析了影响刚性粒子增韧效果的因素。展望了增韧在通用塑料工程化、工程塑料高性能化趋势下的发展前景。     

聚丙烯改性新进展

综述了橡胶或弹性体增韧PP及其机理，刚性粒子增韧及其机理和橡胶／刚性粒子／PP三元复合增韧体系，简要介绍了PP改性技术的最新进展以及PP综合改性的新思路。     

PS SAN 和AAS对PVC／ABS体系增韧改性的研究

采用非弹性体增韧的概念,探讨了三种有机刚性粒子(PS、SAN和AAS)对PVC/ABS二元体系的增韧改性作用,分析了有机刚性粒子增韧作用的影响因素和实现途径。结果表明,有机刚性粒子对PVC/ABS二元共混体系确有一定增韧作用,不同的刚性粒子对不同韧性的二元基体,增韧改性效果各不相同。     

无机刚性卡粒子增韧UPVC研究进展

概述了无机刚性粒子增韧改性UPVC的研究及发展的现状,阐述了无机刚性粒子增韧UPVC的机理及影响因素,总结目前国内增韧UPVC的无机刚性粒子的种类、方法、特点以及UPVC/无机刚性粒子复合材料的应用.     

无机刚性粒子增韧UPVC研究进展

概述了无机刚性粒子增韧改性UPVC的研究及发展的现状,阐述了无机刚性粒子增韧UPVC的机理及影响因素,总结目前国内增韧UPVC的无机刚性粒子的种类、方法、特点以及UPVC/无机刚性粒子复合材料的应用。     

弹性体增韧机理浅析

本文从增韧理论发展的两个阶段入手,对增韧机理进行了简单的论述。进一步分析了银纹—剪切带理论和有机刚性粒子增韧理论与无机刚性粒子增韧理论。     

聚丙烯增韧研究最新进展

系统论述了国内外有关PP增韧改性的研究进展。分别介绍了弹性体或橡胶、热塑性塑料、刚性粒子、刚性粒子协同弹性体、纤维对PP增韧改性的研究现状以及对聚丙烯力学性能、热性能、流变性能的影响,重点介绍了刚性粒子以及刚性粒子协同弹性体对PP的改性研究。刚性粒子协同弹性体能够避免弹性体增韧PP加工上的困难和刚性体在基体中易形成缺陷等问题,充分发挥两者的优势,在对PP增韧改性研究方面具有很大潜力。     

刚性粒子增韧聚氯乙烯的研究状况

详细论述了刚性粒子增韧聚氯乙烯的研究发展状况 ,探讨了刚性粒子的增韧机理。     

核壳型粒子改性聚氯乙烯的发展

分别介绍了国内外有关核壳结构粒子增强增韧PVC的研究工作，核壳结构的粒子包括弹性体、有机刚性粒子和无机刚性粒子。     

刚性微粒对硬聚氯乙烯性能的影响

概述了刚性微粒对硬聚氯乙烯加工性,热稳定性、光老化性以及力学性能的影响,并从结构－加工－性能关系角度分析说明刚性微粒的组成与形态。研究结果表明：聚氯乙烯的塑化状态是决定硬聚氯乙烯性能的关键因素,通过选择适当的刚性微粒,控制塑炼工艺条件可获得性能优异的硬聚氨乙烯材料。     

Liquid spouting of pulp fibers in a conical vessel

Pulp fibers can be spouted in water in a conical vessel. The entities which are spouted are fiber flocs rather than individual fibers. Synthetic fibers, which do not flocculate, cannot be spouted. For comparison, rigid spherical particles were spouted with water in the same conical vessel. Liquid spouting of rigid particles was similar to gaseous spouting. For pulp spouting, the minimum spouting velocity is proportional to the mass of fibers in the bed and inversely proportional to the diameter of the inlet. For rigid particles, the minimum spouting velocity is proportional to the height of the bed and inversely proportional to the square of the diameter of the inlet. A model for the minimum spouting velocity was developed for pulp spouting.     

Self-assembly of particles—The regulatory role of particle flexibility

Aspects of the self-assembly of particles, which uses nanometer or micrometer sized building blocks to bridge the gap between microscopic and macroscopic scales, are reviewed. Particle self-assembly has been the focus of considerable research in recent years because it can lead to superstructures with a complexity inaccessible by molecular self-assembly, and functionalities entirely different from or superior to those of the primary particles. Examples in molecular self-assembly suggests that anisotropic interactions could be useful in promoting particle self-assembly, with the exception of colloidal crystallization, which requires particles of uniform size and shape. Anisotropic particles prepared by surface modification of precursor particles are often rigid and submicron or micron sized, and thus relatively strong isotropic van der Waals interactions tend to resist self-assembly into regular superstructures. In addition, the relatively large contact area between particles needed for a sufficient binding enthalpy to stabilize a superstructure is difficult for rigid spherical particles. In contrast, flexible anisotropic polymeric particles dispersed in solvents have been shown to self-assemble into various superstructures. The flexibility of primary anisotropic particles enables them to fuse and stabilize into a superstructure. Some flexible and multi-component particles that are isotropic in common solvents can undergo deformation and sufficient material redistribution to anisotropically self-assemble into regular superstructures in selective solvents. The self-assembly is also driven by anisotropic interactions, which is induced during self-assembly rather than in the particles as synthesized. This review focuses on recent achievements in soft particle self-assembly and describes briefly the advancements in rigid particle self-assembly. The presentation is divided into discussion of self-assembly by the colloidal crystallization of isotropic rigid particles, anisotropic rigid particles, anisotropic soft particles and isotropic soft particles, in that order.     

刚性球粒在PEK-C/PF共混树脂复合材料中的增韧增强

本文探讨了在ＰＦ中加入ＰＥＫ－Ｃ形成的刚性ＰＦ球粒对复合材料的增韧增强,发现超细的刚性ＰＦ球粒的增韧通过界面脱粘,银纹化和树脂空化三种机制实现。其增强主要通过超细的刚性粒子数量的增加与连续相较好的界面结合来提高模量。     

Simulation of the Viscous Sintering of Coated Particles

Problems associated with the sintering of mixtures of hard and soft particles can be obviated by coating the hard particles (e.g., alumina) with a soft phase (e.g., glass). An analysis of the sintering kinetics of such materials based on finite-element simulations of the sintering of a pair of rigid spheres coated with a viscous material is presented. Until the contact radius is greater than the thickness of the coating, the sintering kinetics are very similar to those obtained if the rigid core is not present. The sintering rate decreases as the rigid cores approach each other and is limited by flow in the gap between the core particles. If the coating thickness is in excess of 20%, the simulations predict that a packing of such particles sinters to full density at a rate comparable to that of particles without a rigid core.     

The flow of suspensions through tubes: V. Inertial effects

The behavior of particles undergoing Couette and Poiseuille flows at rates when inertial effects become significant was investigated. The rotation of rigid particles was similar to that in the Stokes flow regime, except for a drift of cylinders to limiting rotational orbits corresponding to the maximum energy dissipation. In Poiseuille flow, rigid particles migrated to an equilibrium radial position which depended on the density difference of two phases, the directions of sedimentation velocity and flow, and the ratio of particle to tube radius. Neutrally buoyant deformable particles always migrated to the tube axis. In concentrated suspensions a plasmatic layer developed near the tube wall as a consequence of radial migration. The formation of this layer modified the velocity profile and caused a reduction in the apparent viscosity coefficient.