石墨烯/聚酰亚胺复合材料的力学和摩擦学性能

采用氧化石墨烯还原法制备了石墨烯,通过溶液共混法制备了石墨烯增强聚酰亚胺复合材料;研究了石墨烯/聚酰亚胺复合材料的力学和摩擦学性能及摩擦学作用机制。结果表明,随着石墨烯含量增加,复合材料的拉伸强度、断裂伸长率和硬度均呈先上升后下降的趋势,而冲击强度呈先升高而后降低,再升高的趋势。当添加1.0%(质量分数)的石墨烯时,复合材料的拉伸强度和断裂伸长率达到最大值,分别比纯聚酰亚胺提高了149%和652%。石墨烯的加入显著降低了聚酰亚胺复合材料的摩擦系数和磨损率;随石墨烯含量增加,复合材料的磨损率先下降后上升,而摩擦系数先显著降低,尔后平缓减小。随载荷增加,复合材料的磨损率呈平缓下降的趋势;而随滑动速率增加,磨损率呈上升趋势。石墨烯增强的聚酰亚胺复合材料的磨损机理为粘着磨损。     

PVC/SEBS-g-MAH共混物制备及性能研究

采用机械共混法制备PVC/SEBS-MAH共混物。研究了增韧剂SEBS-MAH的加入量对共混物冲击性能和拉伸性能的影响。冲击实验和拉伸试验表明,随着SEBS加入量的增加,共混物的简支梁缺口冲击强度、断裂伸长率先提高后降低,而弹性模量、拉伸强度则降低;当SEBS加入量为6%时,共混物的断裂伸长率出现最大值,当SEBS加入量为8%时,共混物的简支梁缺口冲击强度出现最大值。     

PA6/CB超细纤维形态和力学性能研究

以PA6为"岛"组分,LDPE为"海"组分,选用低结构炭黑(LCB)和高结构炭黑(HCB)为颜料组分,用混合纺丝法制备了PA6/LDPE/CB体系的"海岛"纤维及黑色PA6超细纤维。通过光学显微镜和扫描电子显微镜(SEM)分析以及纤维强度测试研究了CB含量和结构对PA6超细纤维形态和力学性能的影响。研究表明:随着LCB和HCB含量的增加,PA6异形"岛"的数量增加,尺寸增大,PA6超细纤维的拉伸强度和断裂伸长率均快速下降。与LCB相比,HCB更容易导致PA6生成异形"岛",加入HCB的PA6超细纤维的拉伸强度和断裂伸长率显著低于具有相同LCB含量的PA6超细纤维。     

聚酰胺6/聚乙二醇共聚物的合成及力学性能研究

采用水解开环聚合法合成了聚酰胺6/聚乙二醇(PA6/PEG)共聚物,测试了产品的相对粘数、热性能、力学性能及产品外观色差。结果表明:在相同的聚合工艺条件下,共聚单体PEG的加入不影响PA6的聚合速率和聚合时间。此外,PEG的加入降低了PA6的结晶温度和熔融焓变。与尼龙6相比,共聚单体PEG的加入提高了尼龙6的缺口冲击强度和断裂伸长率,特别是缺口冲击强度,提高幅度达3倍之多,但拉伸强度有所下降。最后,共聚单体PEG的加入不影响PA6的外观色泽,PA6/PEG共聚物和PA6两者都具有较好的外观色泽。     

PTFE/MoS_2改性PA6/TiO_2的力学和摩擦磨损性能

通过熔融共混的方法制备了复合固体润滑剂聚四氟乙烯/二硫化钼(PTFE/MoS_2)改性聚酰胺6/二氧化钛(PA6/TiO_2)复合材料,研究了复合材料不同测试条件下的摩擦磨损性能、摩擦磨损机理,静态及动态力学性能、熔融结晶性能。结果表明,复合固体润滑剂能显著降低PA6/TiO_2的摩擦系数,并在合适条件下提高耐磨性;加入PTFE/MoS_2,复合材料冲击强度提高,拉伸强度不变;储能模量和玻璃化转变后的损耗模量增大,玻璃化转变温度降低,结晶度降低。     

改性炭纤维增强聚四氟乙烯复合材料的制备

研究了不同处理条件对复合材料拉伸、摩擦性能的影响,并对拉伸断口及磨损表面形貌进行了分析。结果表明,Ar等离子体处理、聚四氟乙烯乳液包覆的炭纤维能有效增大复合材料界面结合力并提高拉伸强度;当处理时间为9 min时,复合材料的拉伸强度为24.3 MPa,断裂伸长率为340%,磨损率为2.4×10-6mm3/N.m;与纯PTFE相比,拉伸强度和断裂伸长率分别提高了48%和100%,磨损率下降55.6%。     

废旧轮胎粉/POE-g-MAH复合改性 PA6的制备与性能研究

以PA6为基体、废旧轮胎粉与POE-g-MAH为复合增韧剂,采用双螺杆挤出机,制备了废旧轮胎粉/POE-g-MAH/PA6复合材料,研究了复合增韧剂含量对复合材料力学性能、熔融与结晶行为、晶体结构、热性能以及微观形貌等的影响.结果表明,复合材料的冲击强度和断裂伸长率随复合增韧剂含量的增加而显著提高,而拉伸强度和弯曲强度则正好相反;DSC、XRD和TGA结果表明,复合增韧剂的加入,提高了PA6基体的结晶速率,却降低了其结晶度、晶体结构的完整性和耐热性能.     

马来酸酐接枝乙烯辛烯共聚物和6K碳纤维混合填充对聚酰胺66性能的影响研究

以6K碳纤维作为主要增强材料,加入相容剂马来酸酐接枝乙烯辛烯共聚物(POE-g-MAH)制备聚酰胺66增强增韧复合材料,对复合材料的摩擦学性能和力学性能进行了表征。通过对比相容剂加入前后材料的摩擦系数、磨损体积以及摩擦界面温度来研究POE-g-MAH的加入对复合材料摩擦学性能的影响;另一方面,POE-g-MAH的加入改善了复合材料的力学性能(对比15%碳纤维情况下):未添加时材料的拉伸强度为47.88MPa,缺口冲击强度为7.47kJ/m2。添加后材料拉伸强度为94.80MPa,其缺口冲击强度可达到9.56kJ/m2。其拉伸强度提高了98%,缺口冲击强度提高了28%。     

纳米碳化锆改性填充聚四氟乙烯-聚苯硫醚复合材料摩擦磨损性能

采用冷压成型烧结工艺法,制备纳米碳化锆(Nano-ZrC)与聚苯硫醚(PPS)填充改性聚四氟乙烯(PTFE)基复合材料。采用邵氏硬度仪、万能材料试验机、扫描电镜分别表征了复合材料的显微结构及力学特性;使用MRH-3型环-块摩擦磨损试验机测试了复合材料在不同实验条件下的摩擦学性能,并通过非接触3D轮廓仪及X射线光电子能谱仪对磨损表面及转移膜进行了检测分析。结果表明:随着纳米碳化锆含量的增加,复合材料硬度上升,拉伸强度、断裂伸长率及冲击强度下降;纳米碳化锆使得复合材料耐磨性得到显著提升,且其体积分数为5%时复合材料摩擦学性能最佳;纳米碳化锆增强了转移膜的物理粘附能力,并促进其化学吸附作用;当载荷提升至300 N,摩擦速度提升至3 m/s时,复合材料摩擦磨损性能大幅降低,转移膜形貌发生明显变化;环境温度(25~140℃)对复合材料摩擦磨损性能影响不明显。     

拉伸对PA6/PET/AX8900薄膜直线易撕裂性能的影响

以PA6为基体，引入PET相，制备五种不同配比的PA6/PET/AX8900复合材料薄膜和双向拉伸薄膜，采用SEM、DMA、DSC等研究了双向拉伸前后PA6/PET/AX8900复合材料薄膜的微观形貌、热力学和结晶行为，探讨了复合材料薄膜的直线撕裂性能、力学性能、阻隔性能和光学性能，同时研究相容剂EAG(AX8900)对PA6与PET相容性的影响。研究结果表明，添加3%AX8900对PA6/PET复合材料薄膜有明显的增容效果，PET在PA6基体中分散良好；当PET添加量从0%增加到35%时，PA6/PET/AX8900复合材料薄膜熔点降低，与此同时，由于PET中刚性苯环的存在，结晶温度从187.01℃下降到183.47℃。力学性能测试显示，当PET添加量为25%时，PA6/PET/AX8900薄膜拉伸强度相较于纯PA6膜提升25%,断裂伸长率基本不变。当拉伸比为3×1时，PET添加量为25%的PA6/PET/AX8900双向拉伸薄膜的拉伸强度较纯PA6提高了88%。直线易撕裂测试结果表明，当PET添加量从0%增加到25%时，复合材料薄膜的撕裂偏差从100%降低到46%。PET添加量为2...     

石墨/聚四氟乙烯/玻璃纤维改性PA6的力学和摩擦磨损性能

采用石墨(Gr)、聚四氟乙烯(PTFE)和玻璃纤维(GF)改性聚酰胺6(PA6),以提高PA6的摩擦磨损性能和力学性能。重点研究了填料组合、配比、载荷和转速对复合材料摩擦磨损性能的影响,通过磨损表面形貌分析探讨了摩擦磨损机理。结果表明:Gr/PTFE/GF混杂改性PA6能明显降低摩擦系数并提高耐磨性,PA6/Gr/PTFE/GF质量比为70/5/10/15时摩擦系数和磨损率最低,且在高转速(40N,1500r/min)下摩擦磨损性能更好,摩擦系数为0.08,比PA6降低了27%,磨损率为5.5×10~(-6) mm~3/(N·m),比PA6降低了1个数量级,且该复合材料的拉伸强度、冲击强度、储能模量和损耗模量都高于PA6。     

Surface topography and wear mechanisms in polyamide 66 and its composites

A study has been made of the tribological behaviour of polyamide 66 (PA66) running against itself, in unlubricated, non-conformal and rolling-sliding contact. Tests were conducted over a wide range of loads and slip ratios using a twin-disc test rig. The wear and friction behaviour of unreinforced PA66 is dominated mainly by three major features: a critical slip ratio under a fixed load and running speed, macro-transverse cracks and a layer of film on the contact surface. Both the wear and friction properties of unreinforced PA66 can be improved considerably by filling with 20wt% PTFE, and the tribological mechanisms are changed significantly. This reinforcement prevents both the initiation and propagation of transverse cracks on the contact surfaces which occurred in the unreinforced material. It also decreases both the wear rate and the friction coefficient substantially. The 30wt% short glass-fibre reinforced PA66 also suppresses the transverse cracks from initiation on the surfaces. A thin film on the contact surfaces plays a dominant role in reducing wear and friction of the composite and in suppressing the transverse cracks. These results offer the prospect of enhanced applicability of PA66 in engineering components.     

In situ microfibrillar morphology and properties of polypropylene/polyamide/carbon black composites prepared through multistage stretching extrusion

Isotactic polypropylene/polyamide/carbon black (PP/PA/CB) composites with microfibrillar morphology were designed and prepared using a multistage stretching extruder with an assembly of laminating-multiplying elements (LMEs). CB was selectively located in PA. With the increase of LME number from zero to seven, the conductive PA/CB phase was found to experience an elongating-breaking-elongating process. This morphological development resulted in the strong dependence of electrical resistivity on the LME number. When no LME was used, PP/PA/CB materials with 2.0, 3.0, or 4.0 wt% (1.0, 1.6, and 2.1 vol%) CB employed were insulators (resistivity: 10¹⁰ Ω cm) due to their droplet morphology. With the introduction of LMEs, a conductive network was formed because of the microfibrillation of the conductive PA/CB phase; these materials became conductors (resistivity: 10⁴–10⁶ Ω cm). The percolation threshold can lower to 1.5 wt% (0.9 vol%). The low resisticity and percolation threshold cannot be obtained through the conventional method.     

不同纳米粒子填充PA6/GF复合材料摩擦磨损性能

利用MM-200型摩擦磨损试验机考察了载荷及不同纳米粒子与玻璃纤维混合填料对PA6复合材料摩擦磨损性能的影响。采用扫描电子显微镜观察分析磨损表面形貌及磨损机理。结果表明:纳米材料与玻璃纤维的协同作用显著改善了材料的摩擦磨损性能,其中纳米Si3N4与玻璃纤维混杂填充的PA6复合材料的耐磨性最佳;纳米SiO2与玻璃纤维混杂填充的PA6复合材料的摩擦性能最佳。     

Friction and wear behavior of carbon nanotubes reinforced polyamide 6 composites under dry sliding and water lubricated condition

The friction and wear behavior of carbon nanotube reinforced polyamide 6 (PA6/CNT) composites under dry sliding and water lubricated condition was comparatively investigated using a pin-on-disc wear tester at different normal loads. The morphologies of the worn surfaces and counterfaces of the composites were also observed with scanning electron microscopy (SEM). The results showed that CNTs could improve the wear resistance and reduce the friction coefficient of PA6 considerably under both sliding conditions, due to the effective reinforcing and self-lubricating effects of CNTs on the PA6 matrix. The composites exhibited lower friction coefficient and higher wear rate under water lubricated condition than under dry sliding. Although the cooling and boundary lubrication effect of the water contributed to reduce the friction coefficient of the composites, the adsorbed water lowered the strength of the composites and also inhibited the formation of transfer layers on the counterfaces resulting in less wear resistance. With the increasing normal loads, the friction coefficient of the composites increased under the dry sliding and decreased under the water lubricated condition, owing to inconsistent influences of shear strength and real contact areas. The specific wear rate of the composites increased under both sliding conditions.     

莫来石与碳纤维协同填充的聚四氟乙烯基复合材料及其摩擦学性能

为了提高聚四氟乙烯（PTFE）的摩擦学性能,采用机械混匀、带温预压及烧结等工艺制备了莫来石和碳纤维填充的PTFE基复合材料,并通过FTIR、XRD、万能材料试验机、洛氏硬度计、DSC及热机械分析分别表征了PTFE基复合材料的显微结构、力学性能和热学性能;然后,使用MRH-3 型高速环块磨损试验机测定了复合材料的摩擦系数和磨损率,通过自制的硅油砂浆磨损装置测定了复合材料在不同温度下的耐砂浆磨损性能;最后,借助3D测量激光显微镜研究了复合材料摩擦面形貌,并分析了摩擦磨损机制。结果表明:莫来石和碳纤维在PTFE体系中起到填充增强作用,20wt%莫来石-10wt%碳纤维/PTFE复合材料的弹性模量由364 MPa增加至874 MPa;20wt%莫来石-10wt%碳纤维/PTFE复合材料的干摩擦系数较大,但其磨损率与纯PTFE相比降低了3个数量级以上,且此复合材料在水摩擦条件下仍能保持较好的摩擦系数和磨损率,摩擦系数为0.157,磨损率为7.40×10-6 mm3·N-1·m-1;此外,20wt%莫来石-10wt%碳纤维/PTFE复合材料在较高温度下仍能表现出良好的耐砂浆磨损性能。所得结论表明改性得到的PTFE 基复合材料的摩擦学性能显著提高,复合材料可用于有杆抽油井防偏磨。      

Experimental investigation on tribological behaviours of PA6, PA6-reinforced Al<Subscript>2</Subscript><Emphasis Type="Italic">O</Emphasis><Subscript>3</Subscript> and PA6-reinforced graphite polymer composites

This article reports on the preparation, characterization and experimental investigation of polyamide 6 (PA6) reinforced with alumina oxide (Al₂O₃) and graphite composites. The test specimens were prepared in an injection-moulding machine by varying the weight proportions of Al₂O₃ and graphite particles blended with PA6. The tribological properties of the composites were observed by using pin-on-disc wear test rig under dry sliding conditions. The worn surfaces of the composites were examined using scanning electron microscope. The addition of Al₂O₃ and graphite significantly enhanced the tribological properties of PA6. The PA6 containing 30 wt% Al₂O₃ and 20 wt% graphite revealed the best tribological behaviours due to the stronger interfacial bonding characteristics with improved wear resistance. Further, the thermal stability of Al₂O₃ and graphite particles was studied through thermogravimetric analysis test. It was also found that further addition of Al₂O₃ and graphite in PA6 had no significant improvement in wear resistance, the co-efficient of friction and heat generation.     

特殊形态结构导电高分子复合材料的电学性能

先使聚丙烯接枝马来酸酐(PP-g-MAH)与炭黑(CB)反应,再与聚丙烯/尼龙6(PP/PA6)共混制备出CB位于两相界面处的PP/PA6/PP-g-MAH/CB导电高分子复合材料,研究了材料的特殊结构和电学性能。结果表明,在PP/PA6/CB体系中CB粒子分布在PA6相,体系的逾渗阈值为2%;而在PP/PA6/PP-g-MAH/CB体系中,CB被PP-g-MAH诱导分布在两相界面处。PP/PA6两相为海岛结构时,PP/PA6/PP-g-MAH/CB体系仍可导电。PP/PA6/PP-g-MAH/CB体系的逾渗阈值降至1.6%,低于PP/PA6/CB体系。体系的正温度效应(PTC)强度远高于PP/PA6/CB体系,在90-135℃范围内不出现负温度效应(NTC)。PP/PA6/PP-g-MAH/CB体系的电学性能归结于其特殊的界面形态结构:导电通道由位于共混物界面处的PP-g-MAH和CB构建而成。     

牛血清环境下等离子喷涂ZrO_2增强羟基磷灰石涂层的摩擦磨损性能

为了研究ZrO_2增强羟基磷灰石(HA)复合涂层在牛血清润滑环境下的摩擦磨损性能,首先,采用等离子喷涂技术在钛合金基体上制备了ZrO_2含量分别为0、15wt%和30wt%的HA生物陶瓷涂层;然后,分析了ZrO_2/HA复合涂层的物相成分和结合强度;最后,采用UMT-3销盘摩擦试验机研究了ZrO_2/HA复合涂层在牛血清润滑环境下的摩擦磨损性能,观察涂层磨损表面微观形貌并分析了磨损机制。结果表明:HA涂层的主要物相为HA,15wt%ZrO_2/HA复合涂层和30wt%ZrO_2/HA复合涂层中的ZrO_2以立方相形式存在,并且衍射峰强度高于HA的。随着ZrO_2含量增大,涂层的结合强度明显增大。ZrO_2/HA复合涂层与纯HA涂层相比,有更好的耐磨性和更低的摩擦系数。纯HA涂层的磨损机制以犁沟效应和磨粒磨损为主,而15wt%ZrO_2/HA复合涂层和30wt%ZrO_2/HA复合涂层的磨损机制为脆性剥落磨损。