聚合物复合材料填充剂的改性

在前人研究的基础之上，归纳总结了聚合物复合材料填充剂的种类，综述了对其进行表面改性的目的、条件、方法、工艺以及对改性结果的表征等。文章还分析了影响填充聚合物复合材料性能的因素，指出了今后发展的方向。     

浅色补强填充剂LEE白滑粉在合成橡胶中的应用

介绍了新型浅色补强填充剂ＬＥＥ白滑粉的组成、物化性质、加工特性、硫化胶性能及应用前景。     

Effects of a Nd—Fe—B magnetic filler on the crystallization of poly(phenylene sulfide)

The crystallization of poly(phenylene sulfide) (PPS) in a polymer–magnetic Nd—Fe—B powder suspension was studied. Isothermal crystallization behavior was analyzed by way of differential scanning calorimetry, and the kinetics were described via the Avrami equation. The Avrami parameters and the crystallization times were strongly affected by both the particle size and the presence of a coupling agent coated on the filler particles. The small Nd—Fe—B particles exhibited long induction and half‐times, whereas the large particles tended to have short crystallization times. Particles ranging from 38 to 150 μ appeared to have similar crystallization times and to have no significant change in the value of Avrami index with melt crystallization temperature. As a result of these analyses, the dynamic mechanical properties were determined to correlate the fundamental polymer crystallization characteristics and the physical properties of the PPS binder. The enhancement of the wetting of the filler to the binder was promoted through the coupling agent, as confirmed by dynamic mechanical testing performed on the samples. The storage modulus typically decreased because of the presence of the uncoated small particles. Conversely, the loss modulus was enhanced because of the presence of the coated small particles in the PPS binder. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1091–1102, 2002     

Filler-induced failure mechanism in plastic-encapsulated microelectronic packages

Based on empirical data, the present work provides a model to prevent filler-induced reliability degradation in plastic-encapsulated LOC (lead-on-chip) packages. According to the model, the maximum size of the silica fillers included in the plastic package body should be smaller than one half of the inter-distance between the device and its overlying lead-frame. In particular, it is shown in the model that the spherical silica particles, which are sometimes trapped in the space between the top surface of the device and the bottom of the lead-frame during the encapsulating process, can induce huge compressive stress on a specific site of the integrated circuit pattern due to the thermal shrinkage of the plastic package body. Further, the present model suggests that tiny fillers squeezed beneath a large trapping filler might directly attack the brittle layer of the device pattern because the compressive force from the large filler particle can develop into huge compressive stress due to the reduced load-carrying area.     

Mechanical properties and thermal stability of rice husk ash filled epoxy foams

Mechanical properties and thermal stability of epoxy foams filled with white and black rice husk ash were studied. Epoxy foams were prepared from a commercial system and filled with different amounts of both the ashes (0, 6.8, 12.8, 18.0, and 22.7 wt %). The incorporation of both the ashes modified the final morphology of the foam, decreasing the average cell size and increasing the number of cells per volume unit. For all filler percentages used, the specific modulus and strength results showed that the white ash is more effective as reinforcing agent than the black ash. The initial degradation temperature was not affected by the content and type of ash used as the filler. The integral procedure decomposition temperature, weight loss, and char residue results were related to the ash type and atmosphere used in the thermogravimetric analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Morphological aspects of rubber fracture and wear

Morphology of carbon black (CB)‐filled rubber was studied with AFM and SEM and the classification of filler agglomerates, based on their internal structure and filler–matrix interactions, has been proposed. It varies according to the activity of CB and the kind of rubber. It has been shown that fracture of rubber starts either inside filler agglomerates (de‐cohesion) or in a filler–matrix interphase (de‐adhesion) initiating wear of the material. Microscopic observations correlate well with TGA and EPR data of wear debris collected during friction of rubber. The increase of thermal stability of CB and the appearance of additional spin signals, respectively, for elongated samples or debris, are proposed to be associated with de‐cohesion or de‐adhesion of the agglomerates. New approach to the fracture of rubber called “fatal agglomerate concept” is presented. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Silicon doped carbon/Cu joints based on amorphous alloy brazing for first wall application

Amorphous ribbon-type filler-metals represent a promising selection for joining heterogeneous materials together. In this work, rapidly solidified ribbon-type Ti based amorphous filler with a melting temperature of 850 °C and a thickness up to 20 μm is used to join silicon doped carbon to pure copper. SEM examinations demonstrate that a high quality brazed joints could be acquired. The brazed seam has a uniform structure and pore free along its entire length. TiC and ZrC are formed near the interface of carbon and filler-metal when the brazing holds enough time. Using very thin Mo and Cu foil (0.2 mm in thickness) as multiple interlayer are very effective to mitigate the thermal stress occurred in the interface between carbon and copper. The shear strength of this carbon-multiple interlayer-copper joint is more than 20 MPa, and the rupture is mainly occurred on the carbon side.     

PP／mPE／无机填料三元复合材料的形态结构和力学性能

采用刚性无机填料对茂金属聚乙烯（mPE)弹性体增韧聚丙烯（PP）二元共混体系进行增强，从而制得PP／mPE无机填料三元复合材料。分别探讨了CaCO3用量对复合材料拉伸性能和低温冲击性能影响，并考察了不同填料的增强效果。实验结果表明，由于弹性体的存在，无机填料的增强作用减弱；共混物的低温冲击强度也因填料的加入而大幅度下降，但经过表面处理的高岭土体系的冲击强度反而提高。SEM断裂形貌显示，未经表面处理的填料和基体的界面结合较弱，而改性高岭土则以层状结构分散于基体中，并呈现牢固的界面结合。     

低翘曲玻纤增强PET复合材料的制备和性能研究

依据降低翘曲的机理，选用不同降低翘曲的方法，制备了系列翘曲玻纤增强PET复合材料，结果表明，具有较高形状对称性的填料，如滑石粉，云母粉和玻璃微珠都能不同程度地降低玻纤增强PET体系的翘曲，非晶聚合物也能有效改进该体系的翘曲性能。     

补强剂和共混工艺对PA/PVC/NBR三元共混弹性体性能的影响

在选择三元共聚尼龙（PA）、聚氯乙烯（PVC）、丁腈橡胶（NBR）为主体材料，制备PA／PVC／NBR（10／30／60）三元共混弹性体的工作基础上，进一步探讨了填料品种和用量，共混温度，加料顺序等因素PA／PVC／NBR三元共混弹性体的影响。试验结果表明：在PA／PVC／NBR（10／30／60）共混体系中，补强型填料的补强效果优于非补强型的填料，6种填料补强效果依次是：快压出炭黑＞半补强炭黑＞白炭黑＞活性重质，CaCO3＞陶土＞滑石粉，快压出炭黑的适宜用量是20－50份。在制备PA／PVC／NBR三元共混物时，适宜的共混温度是122－140℃，并且采用二段法混工艺制得的共混物性能优于采用一段法共混工艺。