橡胶增韧聚合物机理

详细综述了橡胶增韧聚合物机理的研究进展,并对影响增韧效果的诸多结构因素进行了分析和讨论。     

影响橡胶增韧塑料的主要因素

综述了影响橡胶增韧塑料的主要因素,着重探讨了粒子间距对橡胶增韧塑料的影响,最后总结了橡胶增韧塑料的研究重点。     

塑料/橡胶共混物的相结构与增韧作用

塑料性脆，橡胶柔韧。用橡胶与塑料共混可以获得高抗冲共混物，从而拓宽了塑料的用途。另一方面，随着聚合物高度开发，制备新的单体以合成新型聚合物变得越来越困难。而现存的聚合物种类繁多，性能各异，用共混法制备类型新颖、性能优异的聚合物共混物比较容易，从而可获得巨大的技术经济效益。基于上述原因，聚合物共混的研究长期以来是高分子材料学科的最活跃的、长盛不衰的重要研究领域之一。目前为止，有关这一领域的研究报告、专著和专利文献数以万计。     

Toughening of glassy polymers by prepackaged deformation‐activated diluents

The use of low molecular weight liquid rubber diluents in concentrations of ∼ 1%, dispersed finely in the form of submicron‐sized pools, had been demonstrated in the past by Gebizlioglu and colleagues (Macromolecules 1990, 23, 3968) to be an effective source of toughening of brittle glassy polystyrene through deformation‐accentuated plasticization effects of craze matter during the development of craze plasticity. Herein, we present results of a study extending the range of this plasticization effect through the development of a new “precipitation‐molding” process that can routinely incorporate diluent pools of up to 4–5% by volume and can increase the tensile toughness by about a factor of 3 over what was achieved before. The experiments demonstrate that the toughening mechanism operates primarily through a substantial reduction of the craze flow stress that promotes an increase in craze plasticity that renders inactive adventitious inclusions that normally initiate fracture. Experiments with all blends at different temperatures and strain rates indicate that the fracture response can be represented by a universal behavior pattern of a single thermally assisted process of fracture of craze matter where the diluent merely modulates the plastic resistance. However, the experimental results show that the sorption of the diluent that controls the plasticization effect during straining competes against the time‐dependent fracture process and that the toughening effect decreases monotonically with increasing strain rate and decreasing temperature that limits the effectiveness of the process to a range considerably below what is required for impact response. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1469–1490, 1999     

丁二烯和苯乙烯共聚物橡胶在塑料增韧方面的应用

介绍了丁二烯和苯乙烯共聚物橡胶在塑料增韧方面的应用，同时对国内的有关生产及研究工作提出了一些建议。     

双马来酰亚胺树脂增韧改性研究进展

详细介绍了烯类化合物、二元胺、热塑性树脂、橡胶等增韧双马来酰亚胺(BMI)和新型BMI单体合成等的原理、研究进展。分析了这些增韧方法的优缺点及使用范围。     

Mechanical properties of epoxy resin/hydroxyl‐terminated polyester blends: effect of two‐phase structure

In this paper, the effect of two‐phase structure on the mechanism of rubber‐toughening of epoxy resins was studied. Three types of hydroxyl‐terminated polyesters with different molecular weights were synthesized in order to modify epoxy resins to obtain single‐phase (P‐1), critical phase separation (P‐2) and two‐phase (P‐3) structures. The results of dynamical mechanical analysis and scanning electron microscopy distinguished the dissolved and phase‐separated polyesters in the epoxy matrix. The P‐1 system showed the highest dissolved content of polyester in the epoxy matrix, while the P‐3 system exhibited the lowest content. Both dissolved and phase‐separated polyesters proved to be capable of increasing the toughness of modified epoxy resins. The phase‐separated polyester was found to contribute much more to the improvement of toughness. Copyright © 2005 Society of Chemical Industry     

Toughening of glassy polystyrene through ternary blending that combines low molecular weight polybutadiene diluents and ABS or HIPS‐type composite particles

The effectiveness of toughening brittle glassy polymers such as polystyrene (PS) through deformation‐induced plasticization by low molecular weight diluents of polybutadiene (PB) was amply demonstrated in earlier studies. In those applications, surface‐initiated crazes of unusual growth kinetics and stability could produce effective toughening in sheet samples of millimeter thicknesses, but would have been ineffective in more massive parts where crazes could not be initiated in the interiors to promote a plastic response of the entire volume. This shortcoming has now been rectified through the development of ternary blends incorporating into the previous PS/PB blends a critical small volume fraction of ABS‐ or HIPS‐type composite particles that serve to initiate crazes throughout the volume. Thus, we demonstrated in the present study that incorporation of 10% commerical ABS or 20% commercial HIPS into the most effective PS/PB‐3K blend results in tensile toughnesses equal to or exceeding those of commercial ABS or HIPS in full concentration. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2319–2328, 1999     

碳系填充型导电塑料的研究进展

综述了碳系填充型导电塑料的优点、常用制备方法和炭黑、石墨、碳纤维、超导碳粉和碳纳米管等碳系填充型导电塑料的研究进展。高导电碳纤维和高性价比导电填料的开发、导电机理研究的加强及纳米导电填料的应用将是未来碳系填充型导电塑料的研究方向和开发重点。     

废旧塑料分选技术

废旧塑料的回收包括 3个阶段 :收集、分选、加工或再生等步骤。只有清洁的废旧塑料才能生产高质量的产品 ,这需要有效的塑料分选方法。评述了光选、电选、风力分选、密度分选、浮选等废旧塑料分选技术 ,指出浮选在废旧塑料分选方面具备独特优势     

塑料淀粉研究进展

介绍了国内外淀粉塑料的研究开发、生产情况、今后发展趋势,以及各学派对淀粉塑料的不同看法的争议。     

Interaction of toughening mechanisms in a hybrid epoxy system

Interaction between different toughening mechanisms is studied using a heat treated hybrid system, consisting of carboxyl‐terminated butadiene acrylonitrile (CTBN) rubber and EXPANCEL (expandable hollow microspheres) as modifiers for an epoxy resin. It was found that the fracture toughness of the hybrid system is higher than that of either individually EXPANCEL‐ or CTBN‐modified system for a given content of modifier, although the maximum toughness was not substantially high compared with maxima of single modifier systems. Microscopic examination revealed that damage zone due to CTBN particles ahead of the crack reduces due to the presence of EXPANCEL particles and nevertheless its fracture toughness increased. A possibility was deduced that the cavitation due to CTBN assists with promoting compressive stresses around EXPANCEL particles ahead of the crack tip, resulting in increase in fracture toughness. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4470–4475, 2006