【作者】 黄海；

【导师】 林金清；

【作者基本信息】 华侨大学 ， 化学工程， 2006， 硕士

【摘要】 MC尼龙6是60年代初由己内酰胺阴离子聚合新技术发展起来的新型工程塑料，具有聚合温度低、工艺简单、结晶度高、分子量大、机械性能高等优点，得到了广泛的应用。但由于吸水性强、尺寸稳定性差，纯MC尼龙6的应用受到一定的限制。 本论文提出了一种新的制备碳纤维／MC尼龙6复合材料的方法。首先对碳纤维表面的—COOH和—OH官能团进行异氰酸酯化并用己内酰胺封端处理，扫描电镜测试和红外光谱分析结果均表明：碳纤维表面已接枝上了TDI；热失重分析结果表明：碳纤维表面的接枝率为2.69％。然后将得到的碳纤维加入到己内酰胺单体融体中，采用阴离子原位聚合方法成功地制得接枝聚己内酰胺链段的碳纤维／MC尼龙6原位复合材料。 通过差示扫描量热法(DSC)研究了结晶和熔融行为，非等温结晶和等温结晶结果表明：碳纤维提高了复合材料的起始结晶温度和结晶速率，起到了异相成核剂的作用，接枝聚己内酰胺链段的碳纤维较未接枝的碳纤维更明显的提高了复合材料的起始结晶温度和结晶速率，尼龙6的结晶过程主要为成核过程所控制；Jeziorny和Liu方程均能很好地描述样品的非等温结晶动力学，而等温结晶过程符合Avrami方程。非等温结晶后的熔融行为和等温结晶后的熔融行为均表明：碳纤维使复合材料结晶时易于形成稳定性较差的γ晶型，结晶的完善性变差，但接枝聚己内酰胺链段的碳纤维／MC尼龙6原位复合材料中晶体的完善性比未接枝的碳纤维／MC尼龙6原位复合材料好。 用广角X射线衍射法(WAXD)对晶型结构进行研究，表明碳纤维使原生态的样品中α晶型的含量降低，结晶度下降，其中接枝聚己内酰胺链段的碳纤维／MC尼龙6原位复合材料中α晶型的含量比未接枝的碳纤维／Me尼龙6原位复合材料的多，结晶度也较大：样品淬火时，碳纤维有利于基体尼龙6结晶时形成γ型晶体，接枝聚己内酰胺链段的碳纤维更有利于基体尼龙6结晶时形成γ型晶体；淬火后的样品在200℃下退火2个小时后γ晶型完全转变为α晶型。 力学试验结果表明：碳纤维含量为1.5％时的接枝聚己内酰胺链段的碳纤维／MC尼龙6原位复合材料的拉伸强度较纯MC尼龙6有一定的提高(0.6％)，但随更多还原

【Abstract】 As an important class of engineering plastic, MC nylon 6 has developed and used extensively since 1960s with the development of the anionic polymerization of caprolactam for its various merits, including low polymerization temperature, simple process, high crystallinity, high molecular weight as well as excellent mechanical properties, etc. However, because of the strong water absorptivity and poor dimensional stability, the application of MC nylon 6 was limited in a certain condition.In this paper, a new approach for preparing carbon fibre/MC nylon 6 composites was proposed. To begin with, the -COOH and -OH groups on the surface of the carbon fibre were isocyanated followed by stabilized by caprolactam. According to the results of Scaning Electron Microscopy (SEM), the surface of carbon fibre was grafted with TDI. Moreover, IR spectra demonstrated that the surface of carbon fibre was grafted TDI and the stabilized caprolactam end capping. Thermogravimetric analysis demonstrated that the graft ratio was 2.69%.then the carbon fibre was added to melting caprolactam monomer. Subsequently, the carbon fibre was added to the melt caprolactam, and then caprolactam grafted carbon fibre/MC nylon 6 in situ composites were prepared via anionic polymerization.The crystallization and melting behaviors of such materials were investigated by Differential Scanning Calorimetry (DSC). The results of nonisothermal crystallization and isothermal crystallization demonstrated that, carbon fibres could improve both of the initial crystallization temperature and the crystallization rate of the composites, the carbon fibres served as heterogeneous nucleation reagent. Caprolactam grafted carbon fibre could improve the initial crystallization temperature and the crystallization rate more obviously than ungrafted carbon fibre. The crystallization of nylon 6 was determined by nucleation. The nonisothermal crystallization dynamics was well coincident with the rule of both of Jeziorny and Liu equation. isothermal crystallization dynamics fitted to Avrami equation. The melting results after nonisothermal crystallization and isothermal crystallization both demonstrated Carbon更多还原