加工工艺对HDPE/CaCO_3共混体系性能的研究

采用偏光显微镜研究了4种不同加工工艺对改性HDPE结晶结构的影响,并且通过SEM分析方法研究了纳米CaCO_3在HDPE基体中的分散特性。研究结果表明:在HDPE/Ca CO_3共混体系配方不变的情况下,加工工艺d更有利于提高纳米CaCO_3粒子在HDPE基体中的最终分散性和HDPE/CaCO_3共混体系的力学性能。     

PC/PBT共混体系相容性及其性能的研究

根据相容性理论 ,自制了几种PC与PBT的相容剂 ,讨论了相容剂对PC/PBT共混物力学性能的影响。研究表明 :加入相容剂改善了PBT与PC两相间的相容性 ,共混体系力学性能得到提高。通过红外光谱分析得知 ,PBT与PC之间的酯交换反应促进了PBT/PC共混体系的相容性     

废胶粉/塑料共混物的研究进展

介绍了废胶粉(WRP)与塑料共混制备热塑性弹性体/复合材料的研究进展;重点阐述了WRP的种类、粒径、含量以及界面增容方法对WRP/塑料共混物力学性能的影响规律,指出提高WRP与基体间的界面相容性是制备具有优异性能共混物的关键;最后,针对WRP在塑料共混应用中存在的问题提出了今后的研究方向。     

过氧化二异丙苯和酚醛树脂对HDPE/GTR共混物的原位反应性增容

采用过氧化二异丙苯(DCP)和热塑性酚醛树脂(HY-2045)在未添加催化剂时实现了对高密度聚乙烯(HDPE)/废旧轮胎胶粉(GTR)共混物的原位反应性增容, 并研究了其对共混物的微观形貌、 应力-应变曲线、 动态力学性能和结晶性能的影响. 扫描电镜结果显示, 共混物橡塑界面处有大量的纤维状物质同时嵌入到基体相和分散相中, 使得共混物的界面强度得到显著增加, 从而获得较好的综合力学性能. 差式扫描热量(DSC)和X射线衍射(XRD)测试结果表明, 原位增容后的共混物的结晶度显著降低, 致使其明显的拉伸屈服现象消失. 由于反应型增容剂DCP和HY-2045使得共混物在界面处形成化学交联, 尽管其结晶度有所降低, 但是其拉伸强度和断裂伸长率还是得到了显著的增加. 另外, 动态力学性能测试表明, 增容后的HDPE/GTR共混物中GTR相的玻璃化转变峰变宽, 玻璃化转变温度升高.     

过氧化二异丙苯和酚醛树脂对HDPE/GTR共混物的原位反应性增容（英文）

采用过氧化二异丙苯(DCP)和热塑性酚醛树脂(HY-2045)在未添加催化剂时实现了对高密度聚乙烯(HDPE)/废旧轮胎胶粉(GTR)共混物的原位反应性增容,并研究了其对共混物的微观形貌、应力-应变曲线、动态力学性能和结晶性能的影响。扫描电镜结果显示,共混物橡塑界面处有大量的纤维状物质同时嵌入到基体相和分散相中,使得共混物的界面强度得到显著增加,从而获得较好的综合力学性能。差式扫描热量(DSC)和X射线衍射(XRD)测试结果表明,原位增容后的共混物的结晶度显著降低,致使其明显的拉伸屈服现象消失。由于反应型增容剂DCP和HY-2045使得共混物在界面处形成化学交联,尽管其结晶度有所降低,但是其拉伸强度和断裂伸长率还是得到了显著的增加。另外,动态力学性能测试表明,增容后的HDPE/GTR共混物中GTR相的玻璃化转变峰变宽,玻璃化转变温度升高。     

溶液共混母胶法制备纳米石墨/氢化丁腈橡胶复合材料的性能

采用溶液共混母胶法制备了纳米石墨/氢化丁腈橡胶(HNBR)复合材料,研究了其微观结构、硫化性能、力学性能、耐磨性能等,并将其与采用传统机械共混法制备得到的复合材料进行对比.结果表明:溶液共混母胶法可使纳米石墨更加均匀地分散在HNBR基体中;与传统机械共混法相比,用溶液共混母胶法制备的复合材料的硫化性能和力学性能更优,最大综合扭矩、弹性模量、交联程度、硫化速率分别提高了35％,44％,32％,46％,但该工艺对复合材料拉伸强度和耐磨性能的提高作用不明显.     

复合填充改性聚酰亚胺润滑材料的摩擦学性能

采用M-2000型摩擦磨损试验机考察纳米碳酸钙和石墨复合填充聚酰亚胺(PI)润滑材料在不同速度和载荷下与GCr15轴承钢对摩时的摩擦磨损性能,并利用扫描电子显微镜分析PI材料及其对偶件磨损表面形貌。结果表明,单独填充纳米CaCO_3时,聚酰亚胺摩擦因数轻微减小,体积磨损率显著增大,而单独填充石墨后,聚酰亚胺摩擦学性能有显著的改善;纳米CaCO_3和石墨复合填充后,二者存在协同效应,减摩抗磨能力显著提高;PI材料的摩擦学性能与对偶钢环表面转移膜的性质紧密相关,纳米CaCO_3能显著增强转移膜与对偶件的结合强度。     

扩链剂ADR和成核剂LAK对PLLA/PBAT共混物结晶行为和性能的影响

通过熔融共混法制备了左旋聚乳酸(PLLA)/聚己二酸-对苯二甲酸丁二醇酯(PBAT)(80/20,质量份)共混物,研究了添加1质量份扩链剂ADR和1质量份成核剂LAK对PLLA/PBAT共混物结晶行为、力学性能、流变行为和热稳定性的影响。结果表明：加入扩链剂ADR后,PLLA/PBAT共混物的结晶度下降,但韧性和冲击强度提高,PLLA与PBAT之间的相容性得到改善;进一步加入成核剂LAK后,共混物的结晶度显著上升,断裂伸长率和冲击强度下降,但共混物仍具有较好的韧性;扩链剂ADR改善了共混物的成型加工性能和耐热性,进一步加入成核剂LAK后改善效果略有下降;同时加入扩链剂ADR和成核剂LAK后,PLLA/PBAT共混物同时具备高结晶度和良好的性能。     

EPDM/BIIR共混及其并用胶性能研究

为寻求综合性能优异的新型橡胶密封材料,开展三元乙丙橡胶/溴化丁基橡胶(EPDM/BIIR)共混研究,通过体系优选、配方设计与工艺优化制备EPDM/BIIR并用胶,研究其气体阻隔性、耐老化性、相关力学性能与共混比的关系,并与同类产品进行性能对比.结果表明:EPDM与BIIR共混相容性、共硫化性良好,最佳共混比为70∶30;并用胶耐老化性与同类产品相当,气密性、抗压缩永久变形性优于其他同类产品;二者并用实现了性能优势互补.     

基体树脂和纳米颗粒含量对自润滑衬垫摩擦磨损性能的影响

用浸渍方法制备了含有不同比例基体树脂的Kevlar/聚四氟乙烯纤维(PTFE)织物型自润滑衬垫,用MM-200磨损试验机试验评价了制备衬垫的摩擦磨损性能,通过扫描电子显微镜(SEM)对磨损表面观测,探讨了衬垫中基体树脂含量和添加的纳米颗粒对衬垫摩擦磨损性能的影响机理。研究结果表明:衬垫存在一个较优的基体树脂含量范围,在此范围内,衬垫的摩擦磨损性能较为优异;纳米颗粒对衬垫的摩擦学性能和摩擦过程的阶段性变化产生影响,加入纳米颗粒后衬垫的抗磨性能得到明显改善。     

Influence of PP-g-MA Compatibilization on the Mechanical and Wear Properties of Polypropylene/Thermoplastic Polyurethane Blends

Polypropylene/thermoplastic polyurethane (PP/TPU) blends of different weight ratios (75/25 and 25/75) were processed by melt blending using a maleic anhydride–grafted polypropylene (PP-g-MA) copolymer as coupling agent. The influence of the amount of the coupling agent (0, 3, 5, 7, 9, 11 phr) on the mechanical, frictional, and wear properties of the blends were characterized through tensile test, three-point bending, dynamic mechanical analysis (DMA), and ball-on-disc wear tests. PP-g-MA was found to be an effective compatibilizer for PP/TPU blends, and mechanical and wear properties of the blends were proved to be strongly impacted by the amount of coupling agent. Tensile strength of the blends tends to increase with increasing the PP-g-MA content and 9 phr is found to be optimal for both concentrations of the blends. Good miscibility of the blends with increasing compatibilizer content was also verified by DMA. From the wear test results, the compatibilizer was found to be more effective in PP₇₅/TPU₂₅ blends, in parallel with the results of the mechanical tests. The PP₇₅/TPU₂₅ blend with 11 phr PP-g-MA content was superior to the other blends. In addition, in this work, a new model based on image processing is proposed that provides accurate and fast wear rate measurement and detailed information of the wear track, especially in heterogeneous materials. Using the model, the homogeneity of the wear track widths was proved to be strongly impacted and improved by the use of a coupling agent.     

纳米CaCO3半金属摩擦材料摩擦磨损性能的研究

使用定速摩擦试验机研究了纳米CaCO3对半金属摩擦材料性能的影响。结果表明：在半金属材料中，用纳米CaCO3代替普通的CaCO3粉体，在混料过程中，纳米CaCO3粒子粘附在其他颗粒和钢纤维表面上，热压成型过程中，作为粘结剂的树脂材料与这些材料之间的结合强度降低。在摩擦过程中，造成表面颗粒在剪切力的作用下，很容易与基体脱离，从而使得摩擦材料的摩擦因数偏小，而磨损率却大大增加。     

钛酸酯偶联剂含量对磁流变液性能的影响

分别以不同含量的钛酸酯偶联剂为稳定剂,以羰基铁粉为磁性颗粒制备了硅油基磁流变液,比较了不同体积分数钛酸酯偶联剂对磁流变液沉降稳定性和剪切性能的影响.结果表明:磁流变液的沉降稳定性随钛酸酯偶联剂含量增多而下降,添加2%时具有最好的沉降稳定性;添加4%钛酸酯偶联剂时,在400 mT磁场下剪切屈服强度可达20 kPa;并得到...     

Physical and tribological properties of PTFE micropowder-filled EPDM rubber

The physical and tribological properties of ethylene-propylene-diene-rubber (EPDM) filled with polytetrafluoroethylene (PTFE) micropowders, i.e. MP1100 and MP1200 having chemically similar but distinctive microstructural morphology have been investigated. EPDM-PTFE micropowder blends filled with MP1200 having a solid granular structure, showed poor tensile strength and elongation at break but significantly improved tribological properties. It attained both the lowest steady-state friction coefficient and specific wear rate. However, EPDM-PTFE blends containing a fine agglomerated PTFE micropowder of MP1100 showed enhanced physical properties. Its increasing tensile strength and elongation at break with PTFE micropowder loading compared to MP1200-filled EPDM blend was essentially due to its characteristic morphology, which enhanced its dispersion and compatibility with EPDM. It showed specific wear rate similar to MP1200-filled EPDM but resulted in high friction coefficient. Scanning electron microscopy (SEM) of the PTFE micropowders and the corresponding PTFE micropowder-filled EPDM blends suggest that agglomerates morphology, dispersion and interfacial compatibility with EPDM are the key factors influencing physical and tribological properties of these compounds.     

Microscopy and formation of polymer/metal composites

A new class of materials, formed by dispersion of low-melting-point metal alloys in a polymer matrix, has been studied from the point of view of microstructure, interfacial interaction and mechanical properties. The phases in these composites were formed in the same way as for polymer blends and were thus dependent on viscosity ratio, concentration, surface tension and interfacial interactions. Metal alloys of tin and bismuth (Sn/Bi) were mixed with high-density polyethylene (HDPE) and polystyrene (PS) at elevated temperatures. Some preliminary investigations of lead and tin (Pb/Sn) alloys blended with HDPE, PS, polypropylene (PP), polyoxymethylene (POM), polyethylene-terephtalate (PET), polymethylmethacrylate (PMMA), polycarbonate (PC), polyvinylidenefluoride (PVDF) and Polyvinylchloride (PVC) were also undertaken. The composites were characterized by light and electron microscopy, image analysis, electrical conductivity measurements and impact testing. It is shown that the low-melting-point metal alloys can be dispersed in polymers to a submicrometre level by blending. The particle size distribution follows an exponential function, which means that very fine as well as large particles are present. The equilibrium between dispersion and coalescence is very rapidly established during mixing. The average particle size can be controlled by the properties of the matrix, concentration of the metal and processing conditions. An investigation of interfaces revealed that in some cases a chemical interaction between the metal and the polymer can occur. This is apparent by observation of degradation, fluorescence and changes in mechanical properties.     

载荷和转速对HDPE多元复合材料摩擦学性能的影响

为改善高密度聚乙烯(HDPE)的力学性能、自润滑性和耐磨性,以HDPE为基体,通过填充六钛酸钾晶须(PTW)、聚四氟乙烯(PTFE)和滑石粉制备一种HDPE复合材料.在MMW-1型摩擦磨损试验机上测试复合材料在不同载荷和转速下的摩擦因数、磨损率,采用扫描电镜(SEM)分析磨痕形貌,探讨HDPE复合材料的摩擦磨损规律.结...     

金属冷塑成型用润滑剂研究

研究了蓖麻油加入二硫化钼、铝粉、石墨等添加剂后摩擦磨损性能以及极压性能的变化。用四球摩擦磨损试验机进行对比实验,研究了二硫化钼、铝粉、石墨、磁流体对摩擦因数、磨损的影响。结果表明:(1)蓖麻油为基础油,添加二硫化钼等添加剂,能提高蓖麻油的减摩、抗磨和极压性能。(2)含MoS210 g/L,A l粉30 g/L,石墨50 g/L的蓖麻油其减摩、抗磨和极压性能最好。(3)二硫化钼能起到极压添加剂的作用;A l粉能提高润滑油的稳定性;石墨含量是影响润滑剂摩擦因数最主要因素。     

纳米SiO2和MgO在润滑油中的抗磨减摩性

利用超声波纳米粉碎机制得纳米SiO2、MgO混合粉末，采用激光粒度分析仪及透射电镜表征分析了颗粒的粒度及形貌，通过选用合适的分散剂和采用超声波分散的方法，制备出悬浮性、分散性良好的油基纳米抗磨剂。采用摩擦试验机对所制备的产物的抗磨性进行了表征分析；确定了正常供油状态下和无机油状态下，该纳米抗磨剂的摩擦因数及其磨损量。试验表明：将一定量的纳米SiO2、MsO颗粒及合适的分散剂加入润滑油中，可明显提高其抗磨减摩性能及承载能力。