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水相自由基聚合具有快速、高效的特点,是开发大规模、低成本的聚丙烯腈(PAN)基碳纤维原丝生产技术的首选工艺。本文采用该工艺制备了丙烯腈-衣康酸(P(AN-IA))和丙烯腈-醋酸乙烯酯(P(AN-VAc))两种共聚物,再经溶解和湿法纺丝将其制成纤维。采用傅里叶变换红外光谱仪(FT-IR)、场发射扫描电子显微镜(SEM)、旋转流变仪、旋转粘度计、X-射线衍射仪(XRD)和差式扫描量热/热重同步分析仪(DSG/TG)对比研究了两种共聚单体对水相合成PAN聚合物及其湿纺纤维结构与性能的影响。结果表明,与醋酸乙烯酯(VAc)相比,衣康酸(IA)降低了PAN聚合物的颗粒团聚程度和溶液粘度,显著提高了PAN纤维的截面圆整度和结构致密性,大幅降低了热稳定化反应起始温度、提高了热稳定性。这主要归因于IA的两个羧基基团。其改善了PAN聚合物的亲水性,使凝固过程更加缓和;减弱了氰基间的作用力,提高PAN分子链的运动性;能够诱导氰基在低温下发生环化反应。
The rapid and efficient water-based radical polymerization is the first choice for the development of large-scale and low-cost polyacrylonitrile (PAN) -based carbon fiber precursor production technology. In this paper, acrylonitrile-itaconic acid (P (AN-IA)) and acrylonitrile-vinyl acetate (P (AN- VAc)) were prepared by dissolving and wet spinning Made of fiber. Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (SEM), rotational rheometer, rotational viscometer, X-ray diffraction (XRD) and differential scanning calorimetry / (DSG / TG) comparative study of two comonomers on the aqueous phase synthesis of PAN polymer and wet-spun fiber structure and properties. The results showed that compared with vinyl acetate (VAc), itaconic acid (IA) reduced the particle agglomeration degree and solution viscosity of PAN polymer, significantly improved the circularity and structural compactness of PAN fibers, Thermal stabilization reaction start temperature, increased thermal stability. This is mainly due to the two carboxyl groups of IA. It improves the hydrophilicity of PAN polymer and makes the process of solidification softer. The interaction between cyano groups is weakened, the mobility of PAN molecular chain is increased, and the cyclization reaction of cyano group at low temperature can be induced.