Effect of carbon black addition and its phase selective distribution on the stress relaxation behavior of filled thermoplastic vulcanizates

The long term mechanical behavior of thermoplastic vulcanizates (TPV) based on polypropylene (PP) and ethylene propylene diene terpolymer (EPDM) and different types and concentrations of carbon black (CB) has been characterized by means of stress relaxation experiments. Evaluation of the relaxation curves was carried out using the two‐component model allowing a division of the initial stress into different stress components which are caused by different networks available in TPV. The discussion focussed on the background of the stress components, which are originated by the CB addition, the non‐relaxing stress components σ, and σ, as well as the relaxing stress components Δσ^{CB(polymer‐layer)} and Δσ^CB(network). It was found that the concentration and type of CB as well as the phase specific CB distribution strongly affect the non‐relaxing and relaxing stress components. Up to a CB concentration of 9% in the EPDM phase the composite behaves as a thermo‐rheologically simple material because the impact of CB addition on the α‐relaxation of the crystalline PP phase is still negligible. A master curve was created by the horizontal shift of the relaxing stress curves Δσ^Comp(t) to a reference curve. At higher local CB loadings the additional relaxation processes induced by CB addition overlap with the α‐relaxation, thus, no master curve could be made in that case. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Improvement of mechanical performance of epoxy resins filled with cobalt and chromium powders

Epoxy/ powder metal composites have interesting electrical properties, becoming conductors above the percolation threshold. To complete this study, mechanical investigations have been carried out to show the influence of the fillers on the mechanical performance of these composites. In this framework, different epoxy/metallic powders (Cobalt, Chromium) composites were prepared. Scanning Electron Microscopy showed that the dispersion of the metallic fillers in the matrix is almost homogeneous. The dynamic mechanical thermal analysis (DMTA) measurements showed the dependence of the viscoelastic parameters with the frequency, temperature, nature, and content of fillers. The main relaxations observed are the primary α relaxation (associated to the glass transition, T_g) and a secondary β relaxation. A second DMTA run on the same samples showed a slight increase of the T_g. It clearly showed that the used metallic fillers improve the mechanical properties of the obtained composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

填料对生活垃圾降解及渗滤液水质水量的影响

为了考察在生活垃圾中添加具有吸附性和干燥性的填料对垃圾降解速率、渗滤液产生量、渗滤液水质的影响,在实验室建立了五个圆柱形垃圾厌氧填埋反应器,用于模拟垃圾填埋场的运行情况,以不添加填料反应器作对比,其余四个反应器中分别混合加入锯末、活性炭、沸石、报纸作为填料。实验中对五个反应器中的垃圾层高度、渗滤液产生量、产生渗滤液的COD和NH3-N及重金属离子浓度进行了检测。实验结果表明:在垃圾中添加具有吸附和干燥性的填料具有减少渗滤液产量、加速垃圾降解和减少溶入渗滤液中污染物质的作用,整体来看,锯末在发挥这些作用方面要好于其他三种填料。     

均匀设计在红外高发射率涂料配方中的应用

采用配方均匀设计方法,对红外涂料中使用到的高发射率填料进行配方设计,并获得了相应的数学模型,经试验验证,该模型适用性较好;指出了改善红外涂料辐射性能的有效途径,利用该数学模型,选择法向全发射率在某一固定值处或某一范围内的多个组成点制备填料,使用这些填料进行相应试验,分析出粘结剂种类和使用量对红外涂料辐射性能的影响方式,并最终确定出优化的涂料组成配方。     

In-situ growth of layered double hydroxide on montmorillonite nanosheets to improve the flame retardant performance of ABS resin

Layered double hydroxide (LDH) is a widely used flame retardant in polymer materials; however, the poor dispersion due to its high hydrophilic nature results in disappointing thermal stability and fire safety. In this work, LDH was in-situ grown on the disordered montmorillonite (MMT) nanosheets to obtain the hybrid of LDH and MMT nanosheets (LDH@MMT, simplified as LM). Various techniques, including X-ray diffraction, Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, and transmission electron microscope were used to characterize the microstructure of LM. In addition, the acrylonitrile-butadiene-styrene (ABS) composite containing LM and intumescent flame retardant (IFR) was prepared, and its mechanical and flame-retardant properties were also measured. The characterization results demonstrate that the LM exhibits a periodically alternating layered structure. The Limiting Oxygen Index (LOI) of the ABS composite reaches 27.2% with a V-0 rating in the UL-94 vertical burning test, while its flexural strength and tensile strength decrease by only 17.82% and 13.45%, respectively. Furthermore, the heat release rate, total heat release, smoke production rate, and carbon monoxide production rate of the ABS composite present a significant decline in cone calorimeter tests compared with those of pure ABS. The results further indicate that the hybridization could effectively improve the flame-retardant performance of ABS composites and perform lesser impacts on their mechanical properties.     

纸强中填料的检测

介绍和总结了显微分析法和化学分析法检测纸张中的填料组成,为开展科研工作,优化生产原料,改善纸张性能和降低成本提供支持.     

几种造纸填料对废纸浆过氧化氢漂白的影响

本文利用原子吸收光谱对轻质碳酸钙、高岭土、滑石粉、二氧化钛等常用造纸填料的元素组成进行分析。测定了轻质碳酸钙和高岭土两种填料悬浮液不同浓度下的ξ电位。研究填料的存在对纸浆碱性过氧化氢漂白的影响。结果表明，所用填料悬浮液的ξ电位随着填料加入量的增加而绝对值增加且均为负值，纸浆中不同的填料及其用量对过氧化氢纸浆漂白效果有不同的影响。     

有机填料填充聚四氟乙烯复合材料摩擦学及力学性能

采用共混-冷压-烧结-整形的工艺制备有机物填充聚四氟乙烯(PTFE)复合材料,考察相同含量的不同有机填料对PTFE复合材料力学性能和摩擦学性能的影响。结果发现,加入有机填料后,复合材料的拉伸强度降低,但硬度和压缩强度均提高;有机填料有效地改善了PTFE复合材料的摩擦学性能,其中,质量分数15%聚苯酯填充的PTFE复合材料减摩效果最好,质量分数15%聚酰亚胺填充的PTFE复合材料的耐磨损性能最优。相比之下,质量分数15%芳纶填充的PTFE复合材料摩擦磨损性能及力学性能最好,其耐磨损性能较纯PTFE提高了近400倍,而摩擦因数仅为纯PTFE的84%。其原因在于芳纶的加入有效地改变了摩擦机制,能形成均匀连续的转移膜,进而降低了磨损。     

造纸工业若干重要前沿研究课题

简要介绍近来国际造氏专家提出听若干重要前沿研究领域，包括工程纤维的研究与开发，纤维状填料的开发，单段漂白，单向压榨和新型碱回收系统。     

粉体材料在涂料中的应用技术Ⅰ

涂料用颜填料、粉体助剂和纳米材料统称粉体材料。本文重点介绍不同结构及性能的颜填料组合后的复配改性技术和协同增效技术,有效地提升涂料配方设计水平和涂料产品应用效能,为科学合理地选择颜填料提出了指导性的可操作方法。