聚甲醛的耐磨改性研究

选用聚四氟乙烯(PTFE)、石墨、MoS2 3种耐磨改性剂,通过熔融共混法制备聚甲醛(POM)耐磨材料。研究了耐磨改性剂含量对材料力学性能和摩擦磨损性能的影响,并借助扫描电子显微镜(SEM)分析了材料的磨损表面形貌。结果表明,3种耐磨改性剂使POM耐磨材料的力学性能有所下降,但下降幅度并不大。3种耐磨改性剂改性的POM耐磨材料的摩擦磨损性能均得到不同程度的改善,其中PTFE的改善效果最大,当PTFE质量分数为8%时,材料摩擦系数为0.21,较纯POM降低了38%,磨损体积为5×10–4 cm3,较纯POM降低一个数量级。SEM结果表明,PTFE在POM表面形成了均匀分散的转移膜。     

聚甲醛的耐磨改性研究

选用聚四氟乙烯(PTFE)、石墨、MoS2 3种耐磨改性剂,通过熔融共混法制备聚甲醛(POM)耐磨材料。研究了耐磨改性剂含量对材料力学性能和摩擦磨损性能的影响,并借助扫描电子显微镜(SEM)分析了材料的磨损表面形貌。结果表明,3种耐磨改性剂使POM耐磨材料的力学性能有所下降,但下降幅度并不大。3种耐磨改性剂改性的POM耐磨材料的摩擦磨损性能均得到不同程度的改善,其中PTFE的改善效果最大,当PTFE质量分数为8%时,材料摩擦系数为0.21,较纯POM降低了38%,磨损体积为5×10–4 cm3,较纯POM降低一个数量级。SEM结果表明,PTFE在POM表面形成了均匀分散的转移膜。     

固体润滑剂对玻纤PA66复合材料摩擦磨损性能的影响

采用双螺杆挤出造粒制备了不同固体润滑剂改性尼龙66(PA66)的复合材料,复合材料含30%玻纤(GF),对复合材料的力学性能和摩擦磨损性能进行表征,研究了不同润滑剂对材料性能的影响。结果表明,玻纤的添加可以明显提高材料的力学性能,固体润滑剂的加入,材料的力学性能稍微降低,但是变化不大。固体润滑剂聚四氟乙烯(PTFE)、石墨、二硫化钼(MoS_2)中,PTFE的减摩耐磨效果最佳,且PTFE的含量越高,复合材料的摩擦磨损性能越好,且不同润滑剂复配材料的摩擦磨损性能低于相同含量的PTFE。一定范围内,载荷越高,材料的摩擦因数越小;速度越快,材料的摩擦因数越高,但是磨损量随着速度和载荷的增加而显著提高。     

耐磨消音聚甲醛复合材料的开发

在聚甲醛(POM)中添加由主润滑剂、助润滑剂、消音剂、减磨剂及相关助剂组成的复合润滑体系,采用共混改性方法制备了耐磨消音POM复合材料,并将其与纯POM进行对比研究,考察了材料的外观、摩擦磨损性能、消音性能及力学性能。结果表明,耐磨消音POM复合材料耐磨性好,摩擦系数只有纯POM的1/3,比磨损率只有纯POM的48%,极限PV值比纯POM提高了40%;耐磨消音POM复合材料在摩擦试验中全程无噪音产生,摩擦性能在半年测试时间内很稳定;耐磨消音POM复合材料还具有良好的外观及力学性能,成型加工性能优良。     

耐磨改性聚甲醛材料性能研究

本文考察了在聚甲醛树脂中填充超细PTFE粉末制备耐磨改性聚甲醛材料的制备方法与性能变化。制得的耐磨改性聚甲醛材料刚性小幅提高、部分力学性能呈现不同程度的下降趋势、摩擦磨损性能得到改善。     

改性聚甲醛摩擦磨损性能的研究

聚甲醛(POM)分别与摩擦系数很低的聚四氟乙烯(PTFE)和液体润滑油(OIL)共混改性后,其摩擦磨损性能得到了明显的改善。且 POM/PTFE 和 POM/OIL 共混体系也表现出较为理想的力学性能,文章还指出 POM/OIL 的共混方法是其性能得以改善的关键。     

POM/改性PTFE合金的研究

对POM／改性PTFE合金的力学性能、摩擦磨损性能和加工性能进行了研究。结果表明,POM／改改PTFE共混合金综合了POM和PTFE的优点,减摩耐磨性良,尺寸稳定性、耐热性好,是一种理想的自润滑材料。     

聚甲醛/聚氧化乙烯共混体系流变行为的研究

将聚甲醛(POM)与聚氧化乙烯(PEO)熔融共混,制备改性聚甲醛,用熔体指数仪和高压毛细管流变仪研究了POM、PEO及POM/PEO共混体系的流变性能.试验结果表明随PEO含量增加,共混体系熔体指数(MFI)减小.POM表观黏度对温度的敏感性大于PEO,对剪切速率的敏感性小于PEO.随PEO含量增加,共混体系的温度敏感性下降,剪切敏感性增大.在热塑加工中,可通过改变剪切速率,调节熔体黏度,从而控制共混物形态结构.     

PTFE改性玻纤增强MPPO材料力学性能及耐摩擦磨损性能的研究

采用直径为3.0μm的短玻纤(GF)(GF质量分数为20％)增强改性聚苯醚(MPPO),将其与粒径为5～7 μm的聚四氟乙烯(PTFE)微粉和甲基苯基硅油构成摩擦因数较低的耐磨体系.通过熔融共混法制备PTFE改性GF增强MPPO材料(简称MPPO/20％GF复合材料).对MPPO/20％GF复合材料的力学性能、热变形温...     

聚四氟乙烯改性双马来酰亚胺树脂的摩擦性能研究

采用两种成型工艺(工艺a为冷压→340℃烧制10 min→220℃热压60 min→后固化,工艺b为冷压→220℃热压60 min→340℃烧制10 min→后固化)制备了不同比例的PTFE/BMI(聚四氟乙烯/双马来酰亚胺)改性树脂,对其力学性能和摩擦磨损性能进行了研究,并详细探讨了材料的摩擦磨损机制。研究结果表明:采用工艺a制备的改性树脂具有良好的综合力学性能;适量的PTFE对BMI树脂具有明显的增强增韧作用,当w(PTFE)=7.50%(相对于BMI质量而言)时,改性树脂的弯曲强度(93.00 MPa)和冲击强度(9.35 kJ/m2)分别比纯BMI树脂提高了47.63%和99.08%;引入PTFE可明显降低改性树脂的摩擦因数,当w(PTFE)=17.40%时,改性树脂的摩擦因数(0.146)相对最低,并且比纯BMI树脂降低了78%左右。     

Mechanical and tribological properties of polyoxymethylene modified with nanoparticles and solid lubricants

Polyoxymethylene (POM) composites modified with nanoparticles, polytetrafluoroethylene (PTFE) and MoS₂ were prepared by a twin‐screw extruder. The effect of nanoparticles and solid lubricant PTFE/MoS₂ on mechanical and tribological properties of the composites were studied. Tribological tests were conducted on an Amsler friction and wear tester using a block‐on‐ring arrangement under dry sliding and oil lubricated conditions, respectively. The results showed that generally speaking POM nanocomposites had better stiffness and tribological properties than corresponding POM composites attributed to the high surface energy of nanoparticles, except that the tensile strength of three composites and dry‐sliding tribological properties of POM/3%Al₂O₃ nanocomposite decreased due to the agglomeration of nanoparticles. Tribological properties differed under dry sliding and oil lubricated conditions. The friction coefficient and wear volume of POM nanocomposites under oil lubricated condition decreased significantly. The increased deformation resistance supported the increased wear resistance of POM nanocomposites. POM/PTFE/MoS₂/3%Al₂O₃ nanocomposite had the best mechanical and tribological properties of all three composites, which was attributed to the synergistic effect of nanoparticles and PTFE/MoS₂. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

The effect of interface modification between POM and PTFE on the properties of POM/PTFE composites

A plasma technique was applied to modify the surface of polytetrafluoroethylene (PTFE) fiber to improve the compatibility between PTFE and polyacetal (POM). This technique used argon (Ar) plasma to treat PTFE fiber first and then grafting the fiber with acrylic acid (AAc) by peroxidation. The Ar plasma‐treated PTFE (PPTFE) fiber and AAc‐grafted PPTFE (AAc‐g‐PPTFE) fiber were added into POM to increase the wear resistance and to decrease the friction coefficient of POM. The variables of the experiments were plasma treatment time, monomer concentration of AAc, and grafting time. The graft copolymer was characterized by Fourier transform infrared (FTIR) spectroscopy. The stress–strain behavior, impact strength, Taber wear factor, friction coefficient, and morphology of composites were also investigated. The properties of POM/PTFE composites could be successful modified by surface modification of PTFE in this investigation. The impact strength of POM/AAc‐g‐PPTFE composites was more than twice of that of POM/PTFE composites. The Taber wear factor and friction coefficient of POM/AAc‐g‐PPTFE composites decreased markedly. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 800–807, 2000     

Improvements in tribological properties of polyoxymethylene by aramid short fiber and polytetrafluoroethylene

In order to improve tribological properties of polyoxymethylene (POM), the effects of aramid short fibers (ASF) and polytetrafluoroethylene (PTFE) solid lubricants, as two classes of additives, were studied. The appropriate composites of the polymer and the additives were prepared by melt mixing process. Distribution of additives in the polymer matrix was characterized by scanning electron microscopy (SEM). Mechanical properties in tension such as modulus of elasticity, yield stress, and stress-at-break as well as the fracture energy in impact test were studied to explore friction and wear mechanisms of the composites against a smooth steel surface. Tribological measurements showed that both additives reduce friction and wear of the POM. However, both additives reduced fracture energy of POM in impact test, which dismisses the role of abrasive mechanism of wear under applied conditions. On the other hand, tensile results showed that addition of ASF mechanically reinforces POM, while PTFE degrades mechanical properties of this polymer, especially yield stress. Considering the role of yield stress in the adhesive mechanism of friction and wear, this property was used to define tribological behavior of samples. Since ASF induces mechanical stiffening to POM, increase in yield stress improves tribological properties. However, PTFE introduces transfer films at the interface, thus reduction of yield stress is in favor of tribological properties of this composite. Finally, it is shown that frictional heating and contact temperature rise has a significant degrading effect on wear resistance.     

聚四氟乙烯填充聚醚醚酮及其复合材料的研究

利用熔融共混工艺制备了ＰＥＥＫ／ＰＴＦＥ共混物及其复合材料,研究了ＰＴＦＥ对ＰＥＥＫ共混物及其复合材料力学性能和耐磨性的影响,结果表明,ＰＥＥＫ经１０％￣ＰＴＦＥ填充改性,玻纤／碳纤混杂增强后,由于磨损方式的改变,使该复合材料不仅保持了良好的物理力学性能,而且具有较低的摩擦系数,耐磨性也得到明显改善。     

玻璃纤维及石墨增强聚四氟乙烯复合材料摩擦磨损性能的研究

用机械混合、冷压成型和烧结的方法制备了不同质量分数(5%~30%)的玻纤和石墨填充聚四氟乙烯(PTFE)复合材料制品。用M-2000型磨损试验机评价了不同样品在干摩擦下的磨损性能,揭示了填料玻纤和石墨对PTFE复合材料磨损性能的影响,并对磨损机理进行了探讨。用扫描电镜(SEM)对试样磨损形貌进行观察。结果表明:对玻纤进行改性能极大地提高PTFE复合材料的耐磨性能,同时可提高复合材料硬度;玻纤和石墨协同作用,对改善PTFE摩擦磨损性能有比较显著的效果;20%玻纤 10%石墨填充PTFE复合材料有着较好的摩擦磨损性能。     

The effect of surface modified polytetrafluoroethylene on polyacetal/polytetrafluoroethylene blends

Five kinds of blends: polyacetal (POM) and polytetrafluoroethylenes (PTFEs) [pure (PTFE), coupling agent coated (LZ-PTFE), chemical-treated (CPTFE, containing NaF salt), chemical-treated (WPTFE, no NaF salt), coupling agent coated WPTFE(LZ-WPTFE)] were prepared by mechanical blending. The PTFE presented in the blends, had good wear resistance properties. However, the adhesion interaction between the POM and the PTFE was poor, and increasing the PTFE content caused a decrease in the mechanical properties. Using the chemical surface treatment method to etch PTFE could cause treated-PTFE to homogeneously disperse in POM. This result caused the POM/treated-PTFE blends to have higher mechanical properties than those of the POM/PTFE blends. The NaF salt that adsorbed on the CPTFE surface acted as a coupling agent and offered a very strong adhesion interaction between the POM and the CPTFE. The free salt also acted as a nuclei to aid POM in crystallizing. As a result, the POM/CPTFE blends possessed the highest mechanical properties of all the blends and the best wear resistance property of POM/modified-PTFE(LZ-PTFE, LZ-WPTFE, WPTFE, CPTFE) blends. © 1993 John Wiley & Sons, Inc.     

剑麻/钢纤维增强改性酚醛树脂力学和摩擦性能

采用改性酚醛树脂为基体,剑麻/钢纤维混杂为增强纤维,通过辊炼、模压成型工艺制备了剑麻/钢纤维增强酚醛树脂复合材料.研究了剑麻纤维的加入及含量对聚砜改性酚醛树脂复合材料力学性能、摩擦磨损性能及热稳定性能的影响.结果表明:剑麻纤维质量分数为15%、钢纤维为10%时,复合材料的冲击和弯曲强度分别为3.82 kJ/m2和59.6 Mpa,达到最大;随着剑麻纤维含量的增加,复合材料的摩擦系数降低,热稳定性能下降,当剑麻纤维质量分数为10%时,复合材料的摩擦性能优异;复合材料的磨损面呈现黏着磨损和疲劳磨损特征.     

石墨烯对聚四氟乙烯导热和摩擦磨损性能的影响

针对聚四氟乙烯(PTFE)导热性能和耐磨损性能较差的问题,将石墨烯经过氧化氢预处理后,再用硅烷偶联剂KH550对其进行表面改性,然后采用冷压烧结法制备了PTFE/石墨烯复合材料,研究了不同用量下改性和未改性石墨烯对复合材料电性能、导热性能和摩擦磨损性能的影响。结果表明,随着石墨烯用量增加,复合材料的体积电阻率逐渐下降,但在石墨烯质量分数为0%~2%时,复合材料体积电阻率基本处于同一数量级,仍为绝缘材料;当石墨烯质量分数由0%增加至2%时,复合材料的导热系数明显提高,磨损量明显降低,而摩擦系数先升高后降低,但变化幅度较小。与未改性石墨烯相比,KH550改性石墨烯填充的复合材料具有更高的导热性能和摩擦磨损性能。