聚丙烯、炭黑和碳纤维共混填充超高分子量聚乙烯复合材料的力学和摩擦磨损性能

采用模压成型的方式制备超高分子量聚乙烯(UHMWPE)复合材料,通过AG-1型电子万能实验机和MM-200型摩擦磨损试验机分别研究填料对复合材料力学性能和摩擦磨损性能的影响,采用光学显微镜分析复合材料磨损表面的形貌。结果表明:聚丙烯(PP)和无机填料炭黑(CB)或CB与碳纤维(CF)混杂填料的加入使UHMWPE复合材料的拉伸强度降低,弯曲模量和硬度增加,其中UHMWPE/PP/CB/CF复合材料的弯曲模量和硬度增幅大于UHM-WPE/PP/CB复合材料。填料的加入可改善UHMWPE复合材料的摩擦磨损性能,当填料的质量分数为5%时,UHMWPE复合材料的摩擦磨损性能最好,且UHMWPE/PP/CB/CF复合材料的耐磨性能优于UHMWPE/PP/CB复合材料。与UHM-WPE相比,UHMWPE/PP/CB/CF复合材料的摩擦因数和磨痕宽度分别下降了10%和44%,UHMWPE/PP/CB复合材料则分别下降了12%和42%。光学显微镜观察表明填料的加入大大改善了UHMWPE的磨粒磨损,复合材料表面以较浅的犁沟磨损为主要特征。     

基体流动性对无卤阻燃聚丙烯阻燃性能影响的研究

本论文采用膨胀型阻燃剂敌火龙(Deflam)对聚丙烯(PP)进行阻燃改性,研究了Deflam阻燃剂对PP力学性能、流动性、阻燃性的影响。当在PP中添加30%的阻燃剂时,改变阻燃PP中高流动PP的含量,PP复合体系的拉伸强度、冲击强度下降,弯曲强度、弯曲模量明显增大;阻燃PP的阻燃性下降,但是改善了阻燃PP加工性。     

三维多向编织复合材料弯曲模量的理论预测

基于单胞分析模型,采用改进的刚度平均化方法,对三维四向和五向编织复合材料的各单胞及各层的弹性性能进行预测与分析;进一步,利用材料力学理论,推导材料的弯曲模量,分析编织角、纤维体积含量以及试件尺寸对其的影响,并与拉伸模量及试验值进行比较.结果表明,三维编织复合材料的不同胞体及各层之间的弹性性能存在较大差异,并且材料的弯曲模量大于拉伸模量.研究还表明,编织角和纤维体积含量是影响材料弯曲模量的重要参数,弯曲弹性性能受试件厚度的影响比宽度大,当宽度和厚度达到一定尺寸时,弯曲模量会趋于定值.此外,三维五向编织复合材料的弯曲弹性性能明显优于三维四向编织复合材料.     

聚乳酸竹粉复合材料性能影响因素分析

以竹粉、聚乳酸(PLA)为原材料,以模压成型的方法制备竹粉/PLA复合材料,通过测试其力学性能,摩擦磨损性能和吸水性能来分析竹粉的含量对复合材料性能的影响。实验结果表明:当竹粉含量为30%时,复合材料的洛氏硬度值,弯曲强度以及抗摩擦磨损性能达到最高,之后呈下降趋势。竹粉含量为50%时,材料的冲击强度,拉伸强度达到最大值,竹粉含量超过50%之后,开始明显下降。复合材料的吸水性能逐渐增加。综合实验结果来看,竹粉的添加有利于改善力学性能,提高材料的抗摩擦磨损性能和吸水性能。     

碳纤维/玻璃纤维/石墨协同改性PTFE复合材料力学性能

通过机械混合、冷压和烧结成型制备了碳纤维、玻璃纤维和石墨填充协同改性聚四氟乙烯(PTFE)复合材料。对比分析了不同样品的拉伸、冲击和压缩等力学性能。结果表明:玻纤和碳纤维使复合材料冲击强度下降;玻纤使复合材料拉伸强度下降,碳纤维则使复合材料拉伸强度稍有增强;玻纤和碳纤维均使复合材料压缩强度增加,但碳纤维的增强效果更为明显;石墨、玻纤和碳纤维协同增强PTFE复合材料的拉伸强度较高,弹性模量较大,断裂伸长率较高,抗压缩性能明显提高,且材料拉伸时呈塑性断裂,是综合力学性能较好的高性能润滑密封材料。     

短玻璃纤维增强PA66的偏轴拉伸模量和强度研究

对含30%质量分数短玻璃纤维注塑增强PA66材料,按照与注塑方向成0°、30°、45°、60°和90°裁取试验件,进行偏轴拉伸试验,得到了5组试验件的载荷-位移曲线、拉伸模量和拉伸强度。应用45°偏轴拉伸测定了材料的剪切弹性模量。通过对偏轴拉伸模量和强度对比,以及应用复合材料计算剪切模量的结果对比应用各向同性计算的结果,证明了短纤维复合材料并不能当做传统各向同性材料来处理分析,是具有各向异性的材料。分析表明,连续纤维偏轴拉伸模量计算方法对于短纤维复合材料仍然适用,蔡-希尔失效判据也能较好的适用于这种材料。从试验结果和偏轴模量以及强度计算发现,60°是最差承载角。     

不同填料氟橡胶复合材料高温性能研究

为提高氟橡胶(FKM)高温性能,在FKM中分别加入相同质量分数的聚四氟乙烯(PTFE)、气相二氧化硅(SiO2)、纳米氧化锌(Nano-ZnO),采用机械共混法制备3种FKM复合材料;研究常温和160℃高温下3种填料对FKM复合材料力学性能的影响,结合三维形貌和扫描电镜微观形貌,分析FKM复合材料的摩擦磨损机制。结果表明:PTFE填料降低了FKM材料的力学性能,但可提高其高温摩擦性能;Nano-ZnO填料可提高FKM材料常温力学性能,但对高温力学及摩擦性能没有明显改善;Silica填料可显著改善FKM材料常温与高温条件下的抗磨减摩、抗拉伸撕裂等特性;160℃试验条件下,Silica填料可使FKM材料的拉伸强度提高31%,撕裂强度提高142%,摩擦因数降低52%,磨损量减少36.4%;在FKM中添加Silica可提高基体强度,高温摩擦时形成熔融层,使复合材料具有优异的耐磨性能。     

不同填料增强Ekonol/PTFE复合材料力学性能和摩擦学性能的研究

研究了不同的无机填料对Ekonol/PrFE复合材料的力学性能和摩擦学性能的影响,用扫描电子显微镜观察了复合材料磨损后的表面形貌,并探讨了其磨损机制.结果表明:无机填料的加入改善了Ekonol/PTFE复合材料的力学性能和抗磨损性能.添加石墨与MoS2的Ekonol/PrFE复合材料的力学性能最好,当石墨与MoS2的质量分数为5%和3%时.复合材料的力学性能达到最佳值,拉伸强度提高了34%,弯曲强度提高了62%,弯曲模量提高了75%;添加石墨的Ekonol/PTFE复合材料的抗磨损性能最好,磨损体积最大减少了42%,且受外界条件变化的影响较小.SEM分析表明:在低速低载荷下,复合材料主要以粘着磨损为主;在高速高载荷下,主要以磨粒磨损为主.     

苎麻增强环氧树脂复合材料的力学性能

分别以苎麻原麻和碱麻为增强体,KH550为偶联剂,制备了苎麻增强环氧树脂复合材料,研究了偶联剂用量和纤维含量对复合材料力学性能的影响,并对拉伸断口进行了观察。结果表明:当纤维的质量分数为50%,偶联剂用量为2%时,原麻/环氧树脂复合材料的力学性能最好,拉伸强度为172.9MPa,弯曲强度达365.4MPa;当纤维的质量分数为50%,偶联剂用量为3%时,碱麻/环氧树脂复合材料具有最好的拉伸性能,拉伸强度为117.3MPa;当纤维的质量分数为40%,偶联剂用量为3%时,碱麻/环氧树脂复合材料具有最好的弯曲性能,弯曲强度达293.2MPa。     

CPP/PLLA单向纤维骨内固定复合材料制备和性能

研制出高强度、高模量完全降解吸收性CPP/PLLA单向纤维骨内固定复合材料,并测试了该材料的物理力学性能及降解性能。结果表明:随着纤维体积分数Vf的提高,复合材料力学性能增大,Vf=0.42时,弯曲强度为347 MPa,弯曲模量为22 GPa,抗压强度178 MPa,剪切强度85 MPa,高于人体皮质骨的力学性能;在模拟体液Ringer’s降解介质中降解15周,弯曲强度为154MPa,弯曲模量为6GPa,因此,CPP/PLLA单向纤维复合材料可用作松质骨或部分皮质骨的骨内固定材料。     

聚砜/聚碳酸酯/热致液晶聚合物共混体系的流变性及形态

对聚砜（ＰＳＵ）／聚碳酸酯（ＰＣ）／热致液晶聚合物（ＴＬＣＰ）共混体系的流变性及形态进行了研究。结果表明，ＰＳＵ／ＴＬＣＰ＝９５／５、ＰＳＵ／ＰＣ＝７０／３０、ＰＳＵ／ＰＣ／ＴＬＣＰ＝６６．５／２８．５／５三种共混物的表观粘度均比ＰＳＵ的表观粘度低很多，且ＰＳＵ／ＰＣ／ＴＬＣＰ共混物的表观粘度也较ＰＳＵ／ＰＣ的有所下降。形态研究表明，ＰＳＵ与ＰＣ、ＴＬＣＰ具有部分相容性，ＴＬＣＰ以不规则的颗粒状分散在ＰＳＵ／ＰＣ基质中。     

Tribological Characterization of Aromatic Thermosetting Copolyester–PTFE Blends in Air Conditioning Compressor Environment

The tribological behavior of a wide range of compositions using blends of aromatic thermosetting polyester (ATSP) with polytetrafluoroethylene (PTFE) has been investigated. PTFE was chosen as the blending material because of its low coefficient of friction and good performance at high temperatures and resistance to chemicals. ATSP blends were used to specifically combat some of the shortcomings of PTFE like its extremely low wear resistance and poor mechanical properties, and special processing requirements due to its high melt viscosity. Controlled tribological experiments simulating an air conditioning compressor operating with R134a refrigerant under realistic operating conditions were carried out with different ATSP/PTFE compositions, as well as four different state-of-the-art commercially available composites containing carbon fibers, graphite and PTFE. It was found that the newly synthesized composites exhibited superb tribological characteristics as far as low friction and low wear were concerned. The wear performance of PTFE was greatly improved, while it was shown that greater amounts of ATSP used in the blend lead to lower wear and the amount of ATSP did not significantly alter the friction coefficient. Material transfer and development of a weak film on the disk surface was observed, especially for the blends with higher PTFE content.     

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.     

Effect of laser irradiation on abrasive wear of glass fibre polyester composite

Low power laser irradiation improves the wear resistance of glass-fibre-reinforced polyester composites, if irradiation time is restricted to short periods. Laser irradiation (i) enhances crosslinking in unsaturated polyester, (ii) modifies surface microstructure and (iii) increases the hardness of the composite material. Improved mechanical properties, in turn, increase the material's resistance to wear.     

SMA增容PA6/ABS共混物的结构和力学性能

以苯乙烯一马来酸酐共聚@(SMA)D增容剂,研究了共混工艺对PA6/ABS共混物结构和力学性能的影响.结果表明:以ABS为基体时,加入增容剂SMA后,PA6分散相尺寸变小且均匀地分散于ABS中,显著改善了共混物的冲击、拉伸性能;当以ABS为基体、PA6为分散相时,共混物的结构和力学性能强烈地受共混工艺的影响,SMA先与ABS共混,再与PA6共混,共混物的分散相尺寸最小,力学性能最好;当以PA6为基体、ABS为分散相时,共混物的结构和力学性能基本不受共混工艺的影响.     

Preparation and characterisation of oil-containing POM/PU blends

Polyoxymethylene (POM), one of the major engineering thermoplastics, has high strength and stiffness, excellent chemical resistance and superior antifriction and wear resistance. It suffers, however, from poor impact resistance due to its higher crystallinity. In this study we have investigated how to improve the toughness of POM by blending polyurethane (PU) with POM using dual-roller compaction. The influences of PU, silicone oil, a surfactant, and fillers such as ultra-high molecular weight polyethylene (UHMWPE), polytetrafluoroethylene (PTFE), graphite and carbon black, on the mechanical properties of oil-containing POM/PU blends and its self-lubrication performance in dry sliding against AISI1045 steel are examined. The results show that blends of POM with 10 wt.% PU reached the maximum notched Izod-impact strength. The best processing method for oil-containing POM/PU blends, and the optimal compositions of modified POM/PU blends were also determined.     

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.     

格构增强型复合材料板材设计与试验研究

复合材料板材有质量轻和结构强的特点,可用于活动房、方舱和厢式车辆,替代传统的铝合金面层及金属骨架的板材。本文设计了一种格构增强型复合材料夹层结构板材,芯材为硬质聚氨酯泡沫,面层为玻璃纤维/不饱和聚酯树脂复合材料,采用整体模压共固化成型工艺。该板材经过拉伸强度、拉伸模量、拉伸延伸率、线膨胀系数、氧指数及其在规定的高、低温条件下的相关力学性能试验表明,保温隔热性能、力学性能和构造要求满足相关应用要求。     

Modeling of the mechanical behavior of polyethylene/polypropylene blends using artificial neural networks

Polymers possess good thermal and electrical insulation properties, low density, and high resistance to chemicals, thus they have been widely used in industrial applications. Nevertheless, they are mechanically weaker and exhibit lower strength and stiffness than metals. However, their mechanical behavior can be enhanced through different techniques such as blending. Accurate estimation of the mechanical behavior is essential in structural design. Since the process of experimental measurements of a blend’s properties can be costly and time consuming, this paper explores the potential use of artificial neural networks (ANNs) in the field of polymer characterization. It addresses the use of ANNs in modeling the tensile curves and mechanical properties of two commonly utilized polymers (polyethylene PE and polypropylene PP) and their blends. Blends of different proportions have been considered. The experimentally acquired data is used to train and test the neural network’s performance. The key system inputs for the ANN modeler are blend ratio and percent strain, and the system output is the stress. The ANN-predicted outputs were compared and verified against the experimental date. The study indicates that a multilayered ANN can simulate the effect of the blending ratio on the mechanical behavior and properties to a high degree of accuracy. It also demonstrates that ANN approach is an effective tool that can be adopted to reduce cost and time of the experimental work. Moreover, the results show that ANNs demonstrate promising potential in the area of polymer characterization.     

聚四氟乙烯对聚丙烯复合材料等通道转角挤压加工性的影响

研究了聚四氟乙烯（PTFE）对聚丙烯（PP）共混物固态等通道转角挤压（ECAE）加工性及性能的影响.结果表明：在PP中加入少量（小于2%的质量分数）PTFE使PP共混物的摩擦因数从纯PP的0.32减小到0.28,ECAE加工挤出压力从纯PP的130 MPa降低到115 MPa;含有少量PTFE的PP共混物使ECAE加工挤出过程更容易,挤出更稳定,其挤出物呈现出较好的形变均匀性,因此,PTFE对PP共混物的固态ECAE加工具有较大的促进作用,少量PT-FE的加入对PP共混物的力学性能影响较小.