【作者】 吕颖；

【导师】 李国禄；

【作者基本信息】 河北工业大学 ， 材料加工工程， 2016， 硕士

【摘要】 本文从实际工程应用需要出发,为解决MC尼龙热学、摩擦学性能较差的缺点,以润滑剂为改性填料,采用了阴离子聚合法制备出含油MC尼龙,研究了润滑剂的添加对MC尼龙力学性能、摩擦学性能、热学性能的影响。借助于扫描电子显微镜、差热扫描量热仪等多种方法探讨了改性机理,分析了添加不同质量分数的润滑剂、不同催化剂活化剂配比、不同润滑剂种类对材料性能的影响。研究表明:(1)润滑剂的添加使MC尼龙的吸水率降低了13%,熔融温度上升8~11℃,结晶温度上升5~12℃,结晶度有较大提高,热稳定性能提高。但含油量达到8%时,结晶度大幅下降,且熔融所需热量较低,热稳定性较差。(2)添加润滑剂后,MC尼龙的弯曲、压缩强度随着含油量增加而降低,在添加量超过5%时,性能出现大幅下降。MC尼龙的拉伸、冲击性能随着含油量的增加而提高,但在含油量超过5%时,拉伸、冲击性能大幅下降甚至低于纯MC尼龙。当含油量为4%~5%时,综合力学性能较好。(3)含油MC尼龙中添加的润滑剂均匀分散在尼龙基体中,在摩擦学测试中,油滴起到润滑剂的作用,降低了滑动摩擦因数。当含油量超过5%时,含油MC尼龙的滑动摩擦因数降低到0.15。当含油量超过4%时,磨损量显著降低,仅为纯MC尼龙的80%。(4)催化剂主要控制聚合反应的速度,而活化剂主要控制聚合度,即聚合物的分子量。当催化剂用量低时,聚合速度慢,结晶度低,所以弯曲强度、拉伸强度和压缩强度较低;而结晶度低,样品中的非晶部分多,在受冲击时起增韧作用,所以冲击韧性高。(5)催化剂或活化剂用量的改变对材料的结晶度有影响,但结晶度的改变没有改变聚合体的本质结构和磨损机理,对材料的滑动摩擦因数没有明显影响。催化剂活化剂用量的改变对耐磨性有一定影响,结晶度大者其耐磨性高,催化剂活化剂加入量对己内酰胺单体的摩尔比为0.002时耐磨性最好。(6)添加不同润滑剂的MC尼龙性能相差较多,添加润滑剂L2的MC尼龙力学性能较好,添加润滑剂L4的MC尼龙摩擦因数最低,添加润滑剂L2的MC尼龙磨损量最小。更多还原

【Abstract】 From the practical engineering application needs,in order to solve the poor thermodynamic and tribological properties of MC nylon,modified with lubricant as a filler,use the anionic polymerization process oil filled MC nylon,this article studied on the effects of filling lubricant on mechanical properties,tribological properties and thermal properties of MC nylon.The mechanism of modification was discussed by scanning electron microscope(SEM),differential scanning calorimeter(DSC),analyzed the impact of different lubricant content and different ratio of catalyzer and activator on the material properties.The main conclusions can be summarized as following:(1)Lubricant filling reduces the water absorption by 13%,the melting temperature rise 8~11℃,the crystallization temperature rises 5~12℃,the crystallinity has improved greatly,thermal stability is improved.But when the lubricant content of 8%,the crystallinity significantly decreased and melting required lower heat,poor thermal stability.(2)After adding lubricant,MC nylon bending strength,compressive strength decreased with the increase of lubricant content,and the property decreased with the addition of lubricant more than 5%.The tensile and impact properties of MC nylon were increased with the increase of lubricant content,but the tensile and impact properties were significantly decreased or even lower than that of not modified MC nylon when the lubricant content was more than 5%.When the lubricant content is 4%~5%,the comprehensive mechanical properties are better.(3)The lubricant added in the oil filled MC nylon uniformly dispersed in the nylon matrix,in the tribological tests,the oil droplets act as a lubricant,reducing friction coefficient.When the lubricant content is more than 5%,the friction coefficient of oil filled MC nylon reduced to 0.15.When the lubricant content is more than 4%,the wear extent is significantly reduced,only 80% of not modified MC nylon.(4)The catalyst mainly controls the polymerization rate,and the activator mainly controls the degree of polymerization,that is,the molecular weight of the polymer.The low amount of catalyst slow down polymerization speed and degree of crystallinity is low,the bending strength,tensile strength and compressive strength is low.When the crystallinity is lower,the amorphous portion is more.The amorphous portion play a role in toughening by the impact,so the impact toughness is higher.(5)Changing the amount of catalyst or activator has influence on the crystallinity of MC nylon,but the influence on crystallinity didn’t change the essential structure of the polymer and wear mechanism,the material coefficient of sliding friction is not significantly affected.Changing the amount of catalyst or activator has a certain influence on the wear resistance,the high crystallinity with high wear resistance.When the mole ratio of catalyst activator and caprolactam is 0.002,the wear resistance is best.(6)The performance of MC nylon with different lubricant is different,the mechanical property of MC nylon with lubricant L2 is better,the friction coefficient of MC nylon with lubricant L4 is the lowest,and the wear extent of MC nylon with lubricant L2 is minimum.更多还原