国外消息

近年来,越来越广泛地采用尼龙材料制造机械设备的摩擦部件。最近有人研究了各种填料含量对尼龙—6耐磨性及物理机械性能的影响。所用的填料是短玻璃纤维、短碳纤维、石棉、石墨、氧化亚铁、硅油(∏MC—150)和高低压聚乙烯。首先将各组份熔融共混,用压力浇铸法制成     

MC尼龙／Sm2O3纳米复合材料的制备及性能研究

用原位分散聚合法制备了一系列MC尼龙/Sm2O3纳米复合材料,并对其结构和力学性能进行了表征.结果表明,纳米Sm2O3使MC尼龙晶格尺寸发生了一定程度的改变;纳米Sm2O3的加入可以明显改善MC尼龙的力学性能,对MC尼龙同时具有增强和增韧双重效果;MC尼龙/Sm2O3纳米复合材料的力学性能随着纳米Sm2O3用量的增加呈先升高后降低的趋势.当纳米Sm2O3的质量分数为0.5%时,复合材料的拉伸强度和断裂伸长率达到最大值,分别比MC尼龙提高了18.8%和91.5%,当纳米Sm2O3的质量分数为1.0%时,复合材料的缺口冲击强度、穹曲强度和弯曲弹性模量达到最大值,分别比MC尼龙基体提高了36.6%、11.2%和11.5%.     

MC尼龙活性料工业化制备与大型管材生产

总结了MC尼龙产品生产技术现状,介绍了国家863重大科技专项成果--MC尼龙活性料工业化制备与大型管材生产系统,并将改性MC尼龙管材与现有塑料管材做了系统对比.     

尼龙—钢复合管道及附件

尼龙—钢复合管道是把增强MC尼龙离心浇铸在钢管内壁而成的一种复合管道。该管除了具有增强MC尼龙管道具有的强度高、耐磨、耐腐蚀、内壁光滑流阻小、无毒性、无二次污染、不结垢、施工安全方便、使用寿命长等优良特点外，相对增强MC尼龙管道，尼龙—钢复合管的强度更高，适应温度范围更大（-36～150℃），用途更为广泛。为用户节约了大量成本。     

改性MC尼龙在榨糖机轴瓦上的应用

介绍采用在MC尼龙聚合过程中添加纳米CaCO3和石墨制备改性MC尼龙的方法,比较了改性MC尼龙与普通MC尼龙的性能,并用改性MC尼龙制成糖厂榨糖机上的轴瓦,生产试用后可满足用户的使用要求。     

含油MC尼龙的摩擦磨损特性及应用

本文对黑龙江省尼龙厂研制的含油MC尼龙的摩擦磨损性能进行了测试,并与英国尼拉卡斯特有限公司生产的含油MC尼龙进行了比较。结果表明国产含油尼龙的性能基本达到或超过进口材料,比普通MC尼龙和固体润滑剂改性MC尼龙的耐磨减摩自润滑性有明显改善。最后对含油MC尼龙在造纸和橡胶工业上的成功应用做了介绍。     

MC尼龙阻燃性改进浅议

本文简述了MC尼龙适用性阻燃剂和阻燃剂对MC尼龙的物理性能的影响。介绍了阻燃MC尼龙的生产制备方法及市场情况。     

环氧树脂改性MC尼龙/碳纤维/二硫化钼复合材料的研制

利用E-51环氧树脂(EP)改性MC尼龙,并以碳纤维(CF)粉为增强剂、二硫化钼(MoS2)为润滑剂、炭黑为增容剂,制备了MC尼龙复合材料.分别研究了EP,CF粉及MoS2的用量对MC尼龙复合材料性能的影响,并测试了MC尼龙复合材料与钢及铝合金摩擦时的耐磨损性能.结果表明,当MC尼龙用量为100份、EP为1.5份、CF粉为13份、MoS2为6.5份、炭黑为3.5份时,MC尼龙复合材料具有较好的力学性能和摩擦性能.相对于钢,该MC尼龙复合材料与铝合金摩擦时的耐磨损性能较好.     

PPG/PTHF对MC尼龙结晶行为的影响

采用DSC、SEM、解偏振光法研究了共聚醚对MC尼龙结晶行为的影响,发现PPG/PTHF-PA共聚物是一个半相容体系,不同分子量的共聚醚与MC尼龙的相容性不同,随着共聚醚分子量、含量的增加,相容性、结晶度呈现先上升而后下降峰形变化,球晶变小,结晶也不完善.共聚醚在MC尼龙结晶过程中起异相成核作用.研究发现,PPG/PTHF部分向尼龙部分渗透,在尼龙保持完整球晶同时,PPG/PTHF能均匀分散在PA基体中,此时共聚物具有优良的力学性能.     

MC尼龙母模

杭州瓷厂自1985年开始与一厂家共同研制用MC尼龙作母模,今年正式投入使用,实践证明,MC尼龙母模有如下优点:1.憎水性强,易脱模,适用于肥皂液等多种脱模剂;2.加工难度小,能做到器型规格一致;3.轻巧,工作面光洁度较高,操作简便;4.耐磨性好,强度高,热变性能     

玻纤、粉煤灰增强MC尼龙复合材料的研究

利用铸型尼龙(MC尼龙)静态浇铸的原理，通过阴离子聚合制得了玻纤、粉煤灰增强MC尼龙。研究了不同玻纤和粉煤灰质量分数对复合材料性能的影响。结果表明，用这种方法制得的玻纤、粉煤灰增强MC尼龙的机械性能较普通MC尼龙有较大幅度提高，纤维在基体中的分散性好，与基体的粘接性也相当好；加入30％玻璃纤维和10％粉煤灰可使复合材料的拉伸强度提高13．8％、弯曲强度提高32．8％、弯曲弹性模量提高110％、无缺口冲击韧性提高442％、而硬度提高49．6％。     

MC尼龙6/TiO2原位纳米复合材料等温结晶动力学的研究

采用差示扫描量热法(DSC)研究了阴离子原位聚合法制备的铸型尼龙6(MC尼龙6)/TiO2纳米复合材料的等温结晶行为,并应用Avrami方程分析了MC尼龙6的等温结晶动力学过程.结果表明纳米TiO2对MC尼龙6基体具有异相成核作用,使其原位纳米复合材料结晶速率常数变大,半结晶时间变小.Hoffman成核结晶理论计算结果表明,原位纳米复合材料的Kg(与结晶温度无关而与成核方式有关的参数)大于MC尼龙6且随着纳米含量的增加而增加,说明纳米TiO2阻碍了MC尼龙6分子链的运动,同时尼龙6由晶核生长占主导地位逐渐向成核机制占主导地位转变.     

Synthesis and characterization of MC nylon/modified yttrium hydroxide nanocomposites

In this article, monomer casting (MC) nylon is synthesized. MC nylon could replace nonferrous metals in certain applications, including gears, wheels, and other moving parts. However, compared with metals, MC nylon products have poor strength and stiffness, and crack easily, especially at low temperatures. In addition, the dimensional stability of MC nylon is poor, especially in the large casting nylon products, causing significant internal stresses due to shrinkage. Thus, MC nylon cracks easily when cast and molded. The yttrium hydroxide particles are modified by stearic acid and dispersed in the caprolactam. The polymerization time is short due to fast anionic polymerization. Copolymerization with different ratios of yttrium hydroxide particles can be used to prepare the copolymer. The effects of different amounts of yttrium hydroxide on the performance of the monomer casting nylon are studied. The products are characterized using X‐ray diffraction, impact, and tensile testing. When the percentage of modified yttrium hydroxide is 0.3 wt %, the composite exhibits the maximum impact strength, thus the 0.3 wt % of modified yttrium hydroxide is the suitable percentage to enhance the impact strength of MC nylon. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43356.     

Triboelectrification electrostatic potential of graphite/monomer casting nylon composites under dry sliding: Correlation with electrical resistivity and wear mechanisms

The variations of triboelectrification electrostatic potential of graphite (GP)/monomer casting (MC) nylon composites under plane contact dry sliding were investigated and the correlation with electrical resistivity and wear mechanisms were studied. MC nylon could be modified as excellent anti‐triboelectrification materials by a proper addition of GP, although unfilled MC nylon was inclined to generate higher triboelectrification electrostatic potential after friction due to the high electrical resistivity. The triboelectrification electrostatic potential and electrical resistivity of composites can be predicted by the content control of GP. The incorporation of GP filler made considerable contributions, which not only reduced and stabilized the triboelectrification electrostatic potential of composites but also enhanced their lubricating properties and the friction heat dissipation. The influences of PV‐values on the triboelectrification electrostatic potential of composites were less than that of electrical resistivity. Although the severe wear and the formation of transfer films resulted in triboelectrification electrostatic potential of unfilled MC nylon abruptly dropping shortly after the beginning of friction under the high PV‐values, it was conductive property, particle shape and size, distribution and dispersion of GP fillers, and density of conductive network built by GP flakes that played the dominant role in deciding triboelectrification electrostatic potential of composites under various PV‐values. POLYM. COMPOS., 31:1369–1377, 2010. © 2009 Society of Plastics Engineers     

PPES/MC尼龙6中相互作用对MC尼龙6的结晶及熔融行为影响

采用原位共混与溶液共沉淀两种不同的方法制得了PPES/MC尼龙6共混物。通过对共混物的DSC非等温结晶与熔融行为表征,推出共混物之间的相互作用。结果表明两种共混物中PPES对MC尼龙6的结晶都起阻碍作用,溶液共混物中熔融峰温(Tm)相对于MC尼龙6变化不大,而其在原位共混物中的影响很大,使得MC尼龙6的熔融峰温(Tm)向高温移动。更值得注意的是,原位共混物中MC尼龙6的结晶与熔融峰温相对于溶液共沉淀样品中偏移纯MC尼龙6的峰温更明显,说明原位共混物中PPES与MC尼龙6之间的相互作用大于溶液共沉淀共混物中的PPES与MC尼龙6的相互作用。在溶液共沉淀中MC尼龙6的结晶和熔融峰温均比在原位共混物中的高。     

增强尼龙在离心泵密封环上的应用

选用具有良好力学性能及优异摩擦性能的增强尼龙作为离心泵密封环的材料,根据离心泵的结构,给出了密封环的密封结构形式及配合尺寸。试验表明,增强尼龙密封环的使用寿命达8000h以上,耐磨性、耐腐蚀性及抗汽蚀性良好．     

碳纤维增强MC尼龙复合材料吸湿行为研究

采用液态原位聚合法制备了碳纤维(CF)增强浇铸尼龙(MC尼龙)复合材料,研究了其吸湿行为?分别考察了CF体积分数、CF编织结构和外加载荷对MC尼龙／CF复合材料吸湿行为的影响。结果表明,随着CF体积分数的增加,复合材料的平衡吸湿率减小;三维编织结构的CF增强MC尼龙复合材料的吸湿速率及平衡吸湿率均低于长的CF增强MC尼龙;外加载荷使该复合材料的吸湿能力降低。     

改性MC尼龙/玻璃钢复合管的制备与应用

以单体己内酰氨为原料,通过强碱聚合法,制备改性MC尼龙管,再以改性MC尼龙管作为内衬管,其表面经处理后再缠绕玻璃钢,形成尼龙/玻璃钢复合管.该复合管具有良好的耐磨损性、耐压性、施工简便、使用寿命长,可取代金属管.     

环氧树脂改性MC尼龙的研究

针对单体浇铸尼龙(MC尼龙)缺口冲击强度低的缺点,采用环氧树脂(EP)对其进行改性。结果表明,EP改性MC尼龙的优化配方为已内酰胺100份、EP3份、NaOH 0．4份、甲苯二异氰酸酯1．0份,改性后MC尼龙的缺口冲击强度有明显提高,达30．68kJ／m^2。     

Prediction of isothermal crystallization parameters in monomer cast nylon 6

A three-dimensional cellular automaton (CA) model is applied to simulate isothermal crystallization of monomer casting (MC) nylon 6. The kinetics is formulated based on the Kim and Kim's rate theory for spherulite expansion. The probability of distribution of crystalline nuclei and impinging were determined by Monte Carlo method. The spherulite impinging was considered in the simulation through the deduction of overlay of spherulite volume. The number of spherulite nuclei and bulk density of MC nylon 6 after completing crystallization, easily obtained from experiment, were used as input data, allowing one to make predictions on a real time and space scale. Finally, the model was verified by quantitative comparison between the simulation results in this work and experimental data in literatures.