温度对酚醛树脂/丁腈橡胶复合材料摩擦学性能的影响

采用机械共混法将酚醛树脂（PF）与丁腈橡胶（NBR）进行混合而制得PF/NBR复合材料,研究了PF用量对NBR的拉伸性能、撕裂性能及硬度的影响,使用多功能材料表面性能综合测试仪、三维表面形貌仪和扫描电子显微镜对力学性能最优的PF/NBR复合材料试样A 2（添加5份PF）在不同温度下的摩擦性能进行了探究,并与未添加PF的试样A 0进行了对比,此外还对PF/NBR复合材料的磨损机理进行了初步分析。结果表明,当温度超过75 ℃时,试样A 0的摩擦系数曲线整体呈持续上升的趋势,同时其表面有较多孔洞,分子间结合力下降,耐磨性变差,而试样A 2的摩擦系数则基本保持稳定,磨损行为表明其磨损机理由磨粒磨损逐渐转变为黏着磨损;相对于试样A 0而言,试样A 2在高温下仍能保持较好的摩擦性能。     

混炼型聚氨酯橡胶/聚十二内酰胺热塑性硫化胶动态硫化历程与性能

采用动态硫化方法制备了混炼型聚氨酯橡胶（MPU）/聚十二内酰胺（PA 12）热塑性硫化胶（TPV）,通过控制动态硫化时间探究了该TPV的动态硫化历程,同时研究了不同动态硫化阶段共混物的物理机械性能和动态力学性能。结果表明,随着动态硫化时间的延长,MPU/PA 12 TPV逐步完成相转变,在温度和剪切作用下,MPU相由连续相转变为分散相,而PA 12则由分散相转变为连续相;随着动态硫化时间的延长,MPU/PA 12共混物的储能模量升高,损耗模量降低,损耗因子减小。此外,随着动态硫化时间的延长,MPU/PA 12共混物的综合力学性能提高。     

玄武岩纤维和钢纤维含量对树脂基摩擦材料性能的影响研究

以酚醛树脂、丁腈橡胶、重晶石、玄武岩纤维和钢纤维等为原料进行摩擦材料的制备,研究了玄武岩纤维和钢纤维含量对摩擦材料力学性能和摩擦磨损性能的影响.结果表明,当玄武岩纤维含量为10％～25％(质量分数,下同)时,随着纤维含量的减少,摩擦材料的冲击强度增大、压缩强度减小;当纤维总量占30％且玄武岩纤维与钢纤维质量比为1:1时...     

Nickel-based metal−organic framework-derived whisker-shaped nickel phyllosilicate toward efficiently enhanced mechanical,flammable and tribological properties of epoxy nanocomposites

Metal−organic framework-derived materials have attracted significant attention in the applications of functional materials. In this work, the rod-like nickel-based metal−organic frameworks were first synthesized and subsequently employed as the hard templates and nickel sources to prepare the whisker-shaped nickel phyllosilicate using a facile hydrothermal technology. Then, the nickel phyllosilicate whiskers were evaluated to enhance the mechanical, thermal, flammable, and tribological properties of epoxy resin. The results show that adequate nickel phyllosilicate whiskers can disperse well in the matrix, improving the tensile strength and elastic modulus by 13.6% and 56.4%, respectively. Although the addition of nickel phyllosilicate whiskers could not obtain any UL-94 ratings, it enhanced the difficulty in burning the resulted epoxy resin nanocomposites and considerably enhanced thermal stabilities. Additionally, it was demonstrated that such nickel phyllosilicate whiskers preferred to improve the wear resistance instead of the antifriction feature. Moreover, the wear rate of epoxy resin nanocomposites was reduced significantly by 80% for pure epoxy resin by adding 1 phr whiskers. The as-prepared nickel phyllosilicate whiskers proved to be promising reinforcements in preparing of high-performance epoxy resin nanocomposites.     

电致形状记忆复合材料研究进展

从宏观与微观两个角度对电致形状记忆复合材料的形状记忆过程及机理进行阐述,详述了基于不同导电填料如纳米颗粒、连续纤维、短切纤维以及复合填料的电致形状记忆复合材料研究现状及其物理共混、原位聚合、冷冻干燥等制备方法.从均匀的导体单元、导体与基体之间的接口黏结以及导电网络结构等3个方面分析了电致形状记忆复合材料的导电机理并从微...     

端羧基修饰单宁酸/没食子酸环氧树脂复合材料的制备与性能研究

通过A₂+B₃一步法及缩聚反应分别制备生物质超支化聚合物 （CTMTA）和没食子酸环氧树脂（GAER）,采用熔融共混法制备了没食子酸环氧树脂（GAER）/甲基四氢苯酐（MTHPA）/2?甲基咪唑（2?MI）/ 超支化聚合物 （CTMTA）复合材料。利用傅里叶变换红外光谱仪（FTIR）、核磁共振仪（¹H?NMR）、差示扫描量热仪（DSC）、扫描电子显微镜（SEM）、力学性能和吸水率等试验,研究了CTMTA 含量对GAER/MTHPA/2?MI复合体系性能的影响。结果表明,CTMTA的加入能提高复合体系的力学性能和吸水率,降低复合体系的固化温度。当CTMTA含量为1.5 %（质量分数,下同）时,GAER/MTHPA/2?MI/CTMTA复合体系的力学性能和吸水率最佳,拉伸强度、断裂伸长率、冲击强度和吸水率分别比GAER/MTHPA/2?MI体系提高了33 %、37 %、47.6 %和45.5 %。GAER/MTHPA/2?MI/CTMTA复合体系的最佳固化工艺参数为110 ℃/20 min。     

氨丙基低聚硅倍半氧烷及其酰胺化产物的合成与表征

由3-氨基丙基三甲氧基硅烷（NH₂-propyl-silane）出发,在碱催化条件下采用水解缩合一锅法合成了笼形氨丙基硅倍半氧烷（NH₂-propyl-POSS）。红外光谱、核磁共振、电喷雾飞行质谱（ESI-TOF）表征结果表明,合成产物NH₂-propyl-POSS是不同大小笼形结构的混合物,其中T8、T9、T10笼形结构含量较高。由NH₂-propyl-POSS分别与乙酸和丙炔酸进行酰胺化反应,进一步合成了乙酰基丙基POSS（CH₃-CONH-POSS）和丙炔酰基丙基POSS（CH≡C—CONH-POSS）,并通过红外光谱、氢谱、碳谱分析表征了其结构。X射线衍射分析结果表明,3种POSS均为非晶态结构。通过热重分析可知,NH₂-propyl-POSS具有较高的热稳定性。将NH₂-propyl-POSS用于提高环氧树脂（EP）的热稳定性,添加量为5 %（质量分数,下同）时,EP/NH₂-propyl-POSS共混物的玻璃化转变温度（T_g）提高至180.7 ℃,极限氧指数（LOI）为25.2 %。     

PHBV扩链改性及其发泡行为研究

以乙烯⁃甲基丙烯酸缩水甘油酯共聚物（CE）为扩链剂与聚（3?羟基丁酸酯?co?3?羟基戊酸酯）（PHBV）进行熔融共混,制备了扩链PHBV样品,然后采用超临界CO₂（scCO₂）釜压发泡法将其在160 ℃、20 MPa下进行物理发泡,成功制备了不同PHBV泡沫。结果表明,与常压差示扫描量热法相比,采用高压差示扫描量热法测量的各组PHBV的结晶温度和熔融温度略微下降;CE的加入提高了PHBV样品的复数黏度（G'）和储能模量（η^* ）;随着CE含量的增加,PHBV发泡样品的泡孔密度和发泡倍率逐渐增加,泡孔尺寸逐渐减小。     

加捻植物纤维增强聚氨酯复合材料的力学特性与疲劳性能

采用多维植筋法制备了软质聚氨酯泡沫/加捻植物纤维（FPUF/TPF）复合材料,研究了植筋方向、TPF毛羽率及植筋体积分数对FPUF/TPF结合界面、力学性能、耐疲劳性能的影响。结果表明,植筋后复合材料的力学性能及耐疲劳性能均有所提升,植筋体积分数在0.35 %~0.7 %之间时,复合材料能在保证轻质的前提下得到较好的性能增强。植筋后力学性能的增强表现为压陷硬度提升,最高可提升89.69 %;压陷比普遍提高,最高达3.56,提升了37.98 %,支撑性能得到提升;横向植筋样品的滞后损失率普遍降低,作为垫材时样品舒适感提升;纵向植筋样品的滞后损失率普遍升高,缓冲性能有所提升。植筋后复合材料耐疲劳性能的增强表现为抗蠕变抗变形能力提升,长时间使用后变形更小;40 %压陷硬度损失率最低为11.01 %,降低了38.59 %,植筋后的循环次数最高可达空白样品（FPUF）的4.1倍;压缩永久变形率较空白样品降低29.63 %。同时对比发现,横向植筋样品的结合界面优于纵向植筋,毛羽较少的TPF与聚氨酯的界面性能较好,过多的毛羽会一定程度上影响泡孔大小和形态。     

High-temperature mechanical property and thermal shock resistance of Al2O3f/Al2O3 composites

Continuous alumina fiber–reinforced alumina matrix composites (Al₂O_3f/Al₂O₃ composites) were produced via sol–gel process, then the high-temperature mechanical property and thermal shock resistance of Al₂O_3f/Al₂O₃ composites were investigated. The results showed that the composites exhibited excellent high-temperature properties. The mechanical property of the composites was affected by heat treatment (prepared at 1100°C exhibited the most desirable mechanical property). The tensile strength of the composites abruptly decreased at higher temperatures. Although the mechanical property of the composites deteriorated after the thermal shock test was conducted at high temperatures, they exhibited excellent thermal shock resistance. After 50 thermal shock tests conducted at 1300 and 1500°C, the flexural strength of the composites was found to be 124.34 and 93.04 MPa, thus showing a decrease in strength with the increasing temperature.