PAN原丝成形工艺与碳纤维晶体结构和性能的关联性研究

The relevance of the PAN fibers forming process to the structure and mechanical properties of carbon fibers

采用广角X射线衍射方法对不同成形工艺的PAN原丝与碳纤维晶体结构和性能的关联性进行了实验和分析。研究表明:PAN原丝的晶体结构与凝固浴成形和纺丝牵伸工艺有直接关联性,由干喷湿纺成形和高倍纺丝牵伸制备的原丝具有晶粒尺寸较大、晶面间距较小和结晶度较高的特点。干喷湿纺成形工艺制备的原丝在碳化过程中石墨晶体的生长速率大于湿法纺丝,且原丝的PAN准晶体结构对碳纤维乱层石墨晶体结构具有遗传型。干喷湿纺成形和高倍数纺丝牵伸更容易获得兼具较高拉伸强度和较高拉伸模量的碳纤维。

The crystal structure of Polyacrylonitrile(PAN) fibers prepared by Wet spinning and Dry jet wet spinning, as well as its relevance to the structure and mechanical properties of carbon fibers(CFs) were investigated by Wide angle X-ray diffraction. The results indicated that the forming of as-spun fiber in coagulating bath and drawing process has relative effect on the crystal structure of PAN fibers. PAN fibers prepared by Dry jet wet spinning with high draw ratio possess a larger crystal size, smaller interplanar spacing and higher crystallinity degree. During the carbonization, the graphite crystal growth rate of CFs prepared by Dry jet wet spinning PAN fibers is faster than those prepared by Wet spinning PAN fibers. Thus, the process of Dry jet wet spinning with high draw ratio is easier to obtain CFs having both higher tensile strength and higher tensile modulus.