热处理对玻璃纤维布/聚苯硫醚非织造布复合板材力学性能的影响

以玻璃纤维布和聚苯硫醚（PPS）非织造布分别作为增强体和树脂基体原料,采用热压成型法制备出玻璃纤维布/PPS非织造布复合板材,然后在烘箱中进行热处理。利用万能试验机（Instron）、XRD、偏光显微镜（PLM）和SEM等手段对玻璃纤维布/PPS非织造布复合板材的力学性能、结晶度、晶粒类型和尺寸及微观形貌等进行了测试和表征。结果表明：随着热处理温度和时间的提高,玻璃纤维布/PPS非织造布复合板材的弯曲强度、弯曲模量和缺口冲击强度得到明显提高。当热处理温度为220℃、热处理时间为2 h时,其力学性能最佳,其弯曲强度、弯曲模量和缺口冲击强度分别达到285.7 MPa、7.8 GPa和85.0 MPa。和未进行热处理的玻璃纤维布/PPS非织造布复合板材相比,分别提高了63.2%、469.0%和37.8%。微观形貌结果表明,玻璃纤维布/PPS非织造布复合板材界面粘结得到了明显改善。     

Mechanical and tribological properties of PA66/PPS blend. II. Filled with PTFE

The mechanical and tribological properties of 70 vol % PA66/30 vol % PPS blend filled with different content of polytetrafluoroethylene (PTFE) were studied in this paper. It was found that the addition of PTFE impairs the mechanical properties of PA66/PPS blend, but greatly increases the wear resistance and decreases the friction coefficient. When PTFE content exceeds 20 vol %, the friction coefficient of composite is minimum (0.15) and lower than that of pure PTFE under the same conditions (0.22). The lowest wear volume (0.44 mm³) is obtained with PA66/PPS/30 vol % PTFE composite, which decreased by 91% compared with unfilled PA66/PPS blend (4.99 mm³). The topography of transfer film and the elemental distribution were investigated by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometer (EDS), respectively. Because of the characteristic crystalline structure, PTFE preferentially transferred to the steel ring surface and formed a thin, uniform and firmly adhered transfer layer, which reduced the ability of PA66/PPS blend to transfer and prevent the adhesion between the sample and the couterface. In addition, the superior lubrication of PTFE inhibited the frictional heat melting during sliding. All these aspects are close related to the friction and wear behavior of PA66/PPS/PTFE composite. Upon the addition of PTFE, thermal control of friction regime is not applicable to the PA66/PPS blend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 969–977, 2006     

多项式相位信号参数估计新方法*

改进了多项式相位变换,并提出了多相位信号参数估计方法。仿真证明了在较低信噪比的情况下,参数估计的均方误差接近Cramer-Rao界。采用傅里叶系数插值的频率估计算法提高了该方法的运算速度。分析和仿真结果证明了该方法的有效性。     

特种工程塑料发展现状和进展

叙述了聚酰亚胺、聚砜、聚苯硫醚、聚醚醚酮和聚醚砜等特种工程塑料的发展现状和市场进展。     

PPS复合导热材料的研究与有限元模型分析

通过有限元分析软件ABAQUS,模拟了三氧化二铝(Al2O3)填充聚苯硫醚(PPS)两相复合材料逾渗结构以及Al2O3填充PPS合金三相复合材料双逾渗结构,并将得到的理论导热率与实验结果进行对比验证,分析了填料分布情况对材料热导率的影响。模拟结果表明:只有当导热填料含量超过逾渗阈值,其导热性能才能有明显的提高,双重逾渗结构的形成,能有效降低逾渗阈值。SEM分析表明,选用不同的合金组分,由于相容性的差异和黏度的差异,填料在PPS合金中的分布情况也有不同,热导率也有较大的差异。在所述配方中PPS/UHMWPE/Al2O3(质量比为35:15:50)复合体系热导率最高,可达1.592W/(m.K),而同质量配比的PPS/PS/Al2O3复合体系的最低,只有0.639W/(m.K)。     

Friction and wear of PPS/CNT nanocomposites with formation of electrically isolating transfer films

The effects of various fillers, i.e. short carbon fibers (SCF), graphite flakes, carbon nanotubes (CNT) and their combinations, on the tribological behavior and transfer film structures of polyphenylensulfide (PPS) were investigated. The hybrid composite filled with combined SCF, graphite and CNT shows the best tribological performance among the composites studied due to a fast formation of a groove-filling transfer film on the counterpart. Especially when measuring the electrical conductivity of the sliding contact during the friction process, a close relationship between the tribological behavior and the structure of the isolating transfer film was evident.     

聚苯硫醚短纤维纺丝油剂的研制

采用了烷基磷酸酯盐、烷基醚磷酸酯盐和两性表面活性剂的复合抗静电体系,并以特种聚醚为摩擦调整剂,开发出具有优异的抗静电性、较高的油膜强度、适宜的摩擦特性以及良好表面特性的聚苯硫醚短纤维纺丝油剂.实践表明:该油剂具有很好的可纺性、梳理性和成纱性,能满足聚苯硫醚短纤维纺丝和后加工的要求.     

耐高温针刺过滤材料性能的研究

对PTFE、PPS和P84三种耐高温针刺过滤材料进行了物理性能和过滤性能测试;研究了在类似的工艺条件下三种过滤材料的过滤性能,并与国家标准的技术要求进行对照,分析三种过滤材料的优缺点及适用的工况条件,为袋式除尘器过滤材料的选用提供依据。     

消防员化学防护服面料用涂层织物的研究

化学防护服是消防员进入化学毒剂和化学危险物品和腐蚀性物品火灾或事故现场进行灭火战斗时必须穿着的个人防护装备。选择聚四氟乙烯(PTFE)薄膜在聚苯硫醚(PPS)织物表面覆膜,以求涂层后织物达到一定的耐化学品渗透性能。先将混有硅烷偶联剂的PTFE乳液处理PPS织物表面,并形成一层牢固的高分子改性膜;进而将PTFE薄膜覆在改性后PPS织物表面,进行热压复合;最后按照GA 770—2008标准对外层面料要求,测试涂层织物的基本力学性能以及阻燃性。耐化学品渗透试验按照EN 374标准进行。测试结果表明,涂层织物的阻燃测试和耐化学品渗透性能均符合GA 770—2008标准的要求。     

基于GPSD的高精度校时系统

天文观测设备对于控制系统的时间准确度有严格要求。为此,采用搭建高精度NTP服务器的方法实现系统校时。基本思路是从NMEA0183数据中提取时间信息,通过PPS信号来保证高精度。具体实现方法是采用GPS接收模块G591来构造硬件电路,软件部分需要NTP服务器软件和GPSD的正确安装和配置。对照实验表明,基于GPSD的NTP服务器校时精度可以达到微秒量级,工作性能稳定而可靠。