填料填充改性聚甲醛复合材料研究进展

综述了近年来不同无机纤维、无机粒子、有机填料与无机填料混合物及金属及其氧化物对聚甲醛(POM)复合材料改性的研究进展。介绍了填料在POM复合材料改性中的作用,对填料填充改性POM复合材料的发展趋势进行了展望。     

聚甲醛/弹性体/碳酸钙复合材料的研究

用弹性体和CaCO3复合改性POM。采用TPU为增韧剂，CaCO3为增强剂，研究了加工方法、组成比、填料用量、粒径及分散形态等因素对复合材料性能尤其是冲击韧性的影响。结果表明，两步法制备复合材料的冲击韧性大大高于一步法；且纳米级CaCO3填充复合材料的综合性能优于其它粒径大小的填料；适量的弹性体及无机纳米填料的加入利于获得较好的增韧效果，当弹性体用量约为10％，CaCO3用量为3％时，与纯POM相比，冲击强度提高了3倍，弯曲模量与纯POM接近。     

聚甲醛/不同表面修饰二氧化硅纳米复合材料的力学性能、热性能及结晶行为

将氨基改性纳米二氧化硅(RNS)和甲基改性纳米二氧化硅(DNS)分别加入到聚甲醛(POM)基体中,采用熔融共混法在双螺杆挤出机上制备出POM/RNS和POM/DNS纳米复合材料,并对其力学性能、热性能及结晶行为进行了研究。结果表明,当RNS和DNS的含量较低时,可以提高纳米复合材料的拉伸强度和缺口冲击强度,随着纳米填料含量的增加呈先增加后降低的趋势;而弹性模量则随着纳米填料含量的增加而不断增加;RNS的加入能够大幅度提高POM的热分解温度,而DNS则对POM的最大热分解温度影响不大;RNS和DNS均具有较强的异相成核能力,它们的加入可以促进POM结晶温度的上升,并导致POM晶粒尺寸减小。     

基于聚甲醛及其复合材料的摩擦学研究进展

介绍了聚甲醛（POM）的基本物理化学性能,综述了聚四氟乙烯（PTFE）共混、无机粒子填充、添加纳米粒子、纤维增强、绿色填料及多元复合对POM复合材料摩擦磨损性能研究进展,指出今后应加强对多因素协同作用下POM复合材料的磨损机理和绿色POM复合材料摩擦学方面的研究。     

聚甲醛增韧改性的研究进展及应用

简述了聚甲醛（POM）的增韧改性方法,包括弹性体增韧改性、无机刚性粒子增韧改性、合金化增韧改性和复合增韧改性,综述了近些年来对POM进行增韧改性的研究进展,介绍了POM及其改性产品在各领域的应用,并对POM增韧改性的前景作出展望。     

聚甲醛/海泡石纤维复合材料的制备与性能研究

为制备性能优良的聚甲醛（POM）基复合材料,以海泡石纤维（Sep）填充POM制备POM/Sep复合材料。研究硅烷偶联剂KH550表面改性填料对复合材料力学和摩擦学性能的影响。复合材料的力学性能以及摩擦学性能随着Sep含量的增加而改善,当有机改性海泡石纤维（O-Sep）含量为5.0 %（质量分数,下同）时,POM/O-Sep复合材料的拉伸强度、弯曲强度、弯曲模量和冲击性能分别达到最优值68.43 MPa、89.81 MPa、3600.61 MPa和285.5 kJ/m2,与纯POM相比提高了28.6 %、51.9 %、79.1 %和8.8 %;且POM/5.0 %O-Sep复合材料的摩擦因数和磨损量分别达到0.072和3.6 mg,与纯POM相比降低了65.9 %和 35.7 %。     

增韧改性聚甲醛研究进展

综述了近年来增韧改性聚甲醛(POM)的主要方法和研究进展,从弹性体增韧改性、刚性粒子增韧改性、合金化增韧改性、复合增韧剂增韧改性四个方面重点阐述了近年来国内POM增韧改性的最新研究成果,其中,弹性体增韧改性POM是传统的增韧方法,而且工艺上简单易行;刚性粒子增韧改性POM不但可以提高材料的韧性,而且还可以改善材料的强度、刚性和耐热性等,并降低成本,备受关注;合金化增韧改性POM在保持POM本身性能的同时,还改善了合金的耐磨性、韧性等其它性能;复合增韧剂改性POM对POM的增韧作用更加明显。最后对今后增韧改性POM的研究方向提出了建议。     

聚甲醛/水镁石纤维复合材料的制备与表征

以水镁石纤维为聚甲醛(POM)的增强填料,通过熔融挤出法制备了水镁石纤维/POM复合材料,结果表明:在该复合材料体系中,钛酸酯偶联剂是比较理想的水镁石纤维表面改性剂;水镁石纤维对POM可以起到增强作用,当水镁石纤维含量为15%时,弯曲强度增大了12.4%,拉伸强度变化不大;水镁石纤维对POM的结晶温度和熔融温度影响不大,但是结晶度从82.1%降低到66.1%。     

国内外聚甲醛产品的开发及应用

对比分析了国内外主要聚甲醛(POM)生产企业通用型、增强/填充型、增韧型、耐磨/润滑型、耐候型、抗静电/导电型及其它类型POM产品的开发生产情况、主要性能及应用;概述了国内改性POM主要专利情况,指出了国内外POM产品开发方面的差距,并提出相应建议。     

聚甲醛的耐紫外光/耐候改性

研究了紫外光吸收剂、热稳定剂、光稳定剂等复合助剂对聚甲醛(POM)耐候性能的影响,并对改性前后的POM进行了人工加速老化测试和评价。结果表明:经人工加速老化500,1 000 h后,改性POM的拉伸强度、弯曲强度、悬臂梁缺口冲击强度保持率分别达到104.0%和106.0%,106.0%和107.0%,68.9%和62.2%;老化前后改性POM颜色基本没有变化,远优于未经耐候改性POM的相应性能。     

玻璃纤维增强聚甲醛复合材料性能与结构的研究

制备了一系列玻璃纤维增强聚甲醛(POM/GF)复合材料,采用傅立叶变换红外光谱仪、差示扫描量热仪、扫描电子显微镜及万能材料试验机等对POM/GF复合材料的结构与力学性能进行了研究,并详细考察了增容剂二苯基亚甲基二异氰酸酯(MDI)的不同添加量对复合材料性能的影响.结果表明,MDI的加入使得POM/GF复合材料的性能显著提高,并在其添加量为POM质量的0.7%时具有最佳性能.     

Aging of Nanosized ZnO Modified Polyoxymethylene Blends with Ethylene–octene Copolymer

The influence of ethylene–octene copolymer and zinc oxide (ZnO) on structure and tensile stress–strain behavior of polyoxymethylene were investigated before and after ultraviolet weathering. Addition of ZnO considerably improved stress–strain characteristics of the ultraviolet-irradiation impaired composites. Crystallinities of ultraviolet-irradiated composites were affected by numerous competitive processes, including suppression of crystallization in the presence of multiple components in the system, nucleation induced by nanofiller, secondary crystallization and amorphization because of the chain scissions of the macromolecules. Addition of ZnO considerably improved stability of the composites, as testified by corresponding changes in the intensities of hydroxyl and carbonyl absorption peaks.     

滑动轴承聚合物基自润滑材料的开发与应用进展

介绍聚四氟乙烯、聚醚醚酮、聚酰胺、聚甲醛、聚酰亚胺等滑动轴承用自润滑材料的研究开发情况、性能特点及用途,重点介绍了聚醚醚酮基复合材料的共混改性、纤维增强改性、填充改性和表面改性等方面的研究进展和应用情况,并提出了自润滑材料今后的发展方向。     

聚甲醛自润滑复合材料的开发与应用

综述了国内外通过向聚甲醛树脂中添加耐磨聚合物，润滑油及润滑脂，无机润滑剂，纤维材料，金属粉末或薄片，复合润滑剂，以及嵌段共聚，与金属复合改性来制备聚甲醛自润滑复合材料的方法。介绍了八类聚甲醛自润滑复合的主要性能和应用领域，对聚甲醛自润滑复合材料发展发展方向及国内聚甲醛复合改性的状况和前景进行了展望。     

聚四氟乙烯对工程塑料的共混改性研究进展

讨论了聚四氟乙烯（PTFE）对聚甲醛、聚醚醚酮、聚间苯二甲酰间苯二胺、聚苯硫醚、聚酰胺、聚酰亚胺及线型低密度聚乙烯等工程塑料的共混改性问题,通过对PTFE进行适当的表面处理或在改性过程中添加适当的特定成份可以增加PTFE和其它高聚物之间的相容性,表面改性后的PTFE与其它工程塑料共混可显著降低摩擦系数,提高耐磨性能。     

Thermal conductivity and tribological properties of POM‐Cu composites

The polyoxymethylene (POM) composites with different copper contents were prepared by extrusion. The thermal conductivity and tribological behavior of POM‐Cu composites with various contents of copper particles were investigated by a hot disk thermal analyzer and an M‐2000 friction and abrasion testing machine, respectively. The effect of copper particles on the thermal conductivity of POM composites was negligible when copper content was below 10 wt %. As the copper content increased, the thermal conductivity of composites increased and reached 0.477 W m^?1 K^?1 for POM‐25 wt % Cu composite, which increased by 35.9% compared with that of unfilled POM. The incorporation of copper particles into POM reduced the friction coefficient of POM composites. The wear mechanisms of POM‐Cu composites were adhesive and abrasive wear. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

聚甲醛/纳米SiO2复合材料的力学性能、结晶行为及热稳定性研究

以改性纳米SiO2为填料,通过熔融共混工艺制备聚甲醛/纳米SiO2复合材料,对其力学性能、结晶行为及热稳定性进行了研究。结果表明:复合材料的拉伸强度和缺口冲击强度随着SiO2含量的增加呈先增大后减小的趋势,二者分别在SiO2质量分数为3%和1%时达到最大;而弹性模量的情况则有所不同,其随着SiO2含量的增加不断增大。DSC测试结果显示,纳米SiO2具有较好的形核作用,能够促进聚甲醛的结晶温度升高,但会抑制晶粒的生长,导致复合材料结晶度的降低。此外,纳米SiO2还能显著提高聚甲醛的热稳定性。与纯聚甲醛相比,复合材料的最大热分解温度在氮气和空气气氛下分别提高了约41.1℃和24.5℃。     

Friction and wear behavior of the hybrid PTFE/cotton fabric composites filled with TiO2 nanoparticles and modified TiO2 nanoparticles

A chemical grafting method was applied to modify TiO₂ nanoparticles through covalently introducing glycidoxypropyltrimethoxy silicane (KH560) followed by polyoxymethylene onto the particles to overcome the disadvantages generated by the agglomeration of nanoparticles. TiO₂ nanoparticles unmodified and modified were introduced into hybrid polytetrafluoroethylene (PTFE)/cotton fabric composites. Friction and wear test demonstrated that TiO₂ nanoparticles unmodified and modified can significantly increase the wear resistance of hybrid PTFE/cotton fabric composites but cannot reduce the friction coefficient. Fabric composites filled with grafted TiO₂ nanoparticles exhibited a lower wear rate due to the disintegration of agglomeration and the improvement of interfacial adhesion between filler/matrix. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers     

Increasing the electrical conductivity of carbon nanotube/polymer composites by using weak nanotube-polymer interactions

A weak interaction between carbon nanotubes (CNTs) and polymers was found to reduce polymer-wrapping on CNT surface, decrease the contact resistance between CNTs, and increase the electrical conductivity of their composites. Thermodynamic properties such as surface energy of components, filler-polymer interactions, and wettability of carbon/polymer systems were analyzed. It was found that the graphitized CNTs filled polyoxymethylene (POM) system exhibits the weakest CNT-polymer interaction among all the investigated systems and a poor wettability. Consequently, the graphitized CNT/POM composites possess a high electrical conductivity and a low percolation threshold of 0.5 wt.% CNT loading, which is associated with the weak CNT-polymer interaction, low contact resistance between CNTs, good connectivity of CNT networks, and high crystallinity of POM in the composites. The results obtained imply that high-performance composites with optimal CNT-network structures can be designed and fabricated by fully considering the surface properties of components and CNT-polymer interactions.     

Effects of glass fiber on the properties of polyoxymethylene/thermoplastic polyurethane/multiwalled carbon nanotube composites

The effects of epoxy‐functionalized glass fiber (GF) on the electrical conductivity, crystallization behavior, thermal stability, and dynamic mechanical properties of polyoxymethylene (POM)/thermoplastic polyurethane (TPU)/multiwalled carbon nanotube (MWCNT) composites are investigated. The electrical resistivities of POM/5%−20% TPU/1% MWCNT composites are significantly reduced by nine orders of magnitude after the addition of 20% GF because of the formation of TPU‐coated GF structure facilitating the construction of conductive networks. GF has no obvious influence on the crystallization temperature, melting temperature, and degree of crystallinity of POM in POM/TPU/MWCNT composites because of their relatively bigger size compared with POM chains and MWCNTs. The storage moduli of POM/TPU/MWCNT composites are improved by the addition of GF, indicating that POM/TPU/MWCNT/GF composites are promising materials with good electrical and mechanical properties. POLYM. COMPOS., 38:1319–1326, 2017. © 2015 Society of Plastics Engineers