摘要
为了研究聚丙烯腈纤维各级超分子结构形态及结晶的微观形态 ,弄清楚制备碳纤维的过程与所得到纤维结构和性能的关系 ,用透射电子显微镜分析了凝胶网络和皮芯结构的形成及预氧化和炭化过程中纤维结构的演变历程。结果表明 :原丝具有明显的皮芯结构 ,外表层凹凸不平 ,从表层至心部是一层过渡区 ,表层的片层较心部的薄且致密。碳纤维网络骨架间接点的密集程度和原丝的密集程度有直接关系 ,原丝网络骨架的接点密集度低及晶粒组织大 ,随后得到的最终碳纤维密集度低及晶粒组织也大 ,其强度和模量明显高。碳纤维强度主要是纤维中弥散分布的“小晶区”做出的贡献 ;原丝微观结构中 ,“晶区”数量、大小和弥散分布情况以及构成三维空间网络结构的致密程度决定了预氧丝和碳纤维的性能。
It is necessary to make it clear the relationship between the process of making carbon fibers and their structure and properties by studying their supermolecular structure and morphological and crystal structure in different stages. The formation of gel network and skin-core structure was researched during the preoxidation and carbonization stages depending on using the transmission electron microscope(TEM). The result shows that the precursors take on apparent skin-core structure which is rough in outer layer, the transitional zone lies between the outside skin zone and inside core zone, the structure zone outside is thinner and more compact than that of skin zone inside. The compact extent of meshwork of junction for carbon fibers is directly related to that of precursors correspondingly, the more the junctions of the precursors and the smaller the crystallites are, the more the junctions of carbon fibers and the smaller the crystallites are, so the tensile strength and modulus of the resultant carbon fibers are higher. The little crystal zone distribution which is dispersed contributes to the tensile strength of carbon fibers. The amount, size and distribution of little crystal zone which is dispersed, and the compact extent of meshwork in precursors determine the properties of the preoxidated fibers and that of the resultant carbon fibers.
出处
《材料科学与工程学报》
CAS
CSCD
北大核心
2005年第3期325-330,共6页
Journal of Materials Science and Engineering
基金
国家十五期间 863资助项目(2 0 0 2AA30 4 1 30 )
国家自然科学基金资助项目 (597830 0 2 )
关键词
聚丙烯腈纤维
凝胶网络
皮芯结构
网络骨架
polyacrylonitrile fibers
meshwork structure
skin-core structure
net framework.
