熔融纺酚醛纤维快速交联固化工艺研究

以热塑性酚醛树脂为原料,采用熔融纺丝法制备酚醛初生纤维;将酚醛初生纤维浸入盐酸-甲醛交联浴中,常温下预处理一定时间,然后快速加热升温使之交联,制得溶液快速交联酚醛纤维;再将溶液快速交联酚醛纤维在一定温度下进行热处理2h,得到快速交联固化酚醛纤维。探讨了酚醛纤维的快速交联固化工艺,研究了酚醛纤维的结构与性能并与常规盐酸-甲醛交联浴固化法制得的酚醛纤维(简称常规固化酚醛纤维)进行对比。结果表明:酚醛初生纤维浸入盐酸-甲醛交联浴中,其盐酸质量分数为16%,预处理时间为48h时,制得的溶液快速交联酚醛纤维的断裂强度为0.84cN/dtex;溶液快速交联酚醛纤维在热处理温度200℃时,纤维断裂强度达到最大值为1.10cN/dtex;快速交联固化酚醛纤维与常规固化酚醛纤维在失重率为5%,10%,20%时的温度相当,二者相差约3℃,二者在900℃时的质量保持率分别为63.8%,64.1%;快速交联固化酚醛纤维表面光滑,无褶皱、收缩,断面呈韧性断裂,并未出现皮芯结构;采用快速固化工艺制备的快速交联固化酚醛纤维可以达到常规固化酚醛纤维的固化效果。

Study on rapid crosslinking and curing process of melt spun phenolic fibers

As-spun phenolic fibers were prepared by melt spinning from thermoplastic phenolic resin and were immersed in a crosslinking solution of hydrochloric acid and formaldehyde at room temperature for a certain period of time before rapidly heating to crosslinking,hence rapidly solution crosslinked phenolic fibers were produced and were subjected to heat treatment for 2 h at a certain temperature to obtain rapidly cured phenolic fibers.The rapid crosslinking and curing process of phenolic fibers was discussed.The structure and properties of phenolic fibers were studied and compared with those of phenolic fibers(conventional cured phenolic fiber for short)prepared by conventional hydrochloric acid-formaldehyde crosslinking bath curing method.The results showed that the breaking strength of the rapidly solution crosslinked phenolic fibers was 0.84 cN/dtex when as-spun phenolic fibers were immersed in hydrochloric acid-formaldehyde crosslinking bath with 16%hydrochloric acid by mass fraction for 48-h pretreatment;the maximum breaking strength of the rapidly solution crosslinked phenolic fibers reached 1.10 cN/dtex after heat treating at 200℃;the temperature of rapidly crosslinking cured phenolic fibers was almost the same as that of conventional cured phenolic fibers at the weight loss rate of 5%,10%and 20%,with the difference about 3℃,and their mass retention rates at 900℃were 63.8%and 64.1%,respectively;the rapidly crosslinking cured phenolic fibers had smooth surface with no wrinkle and shrinkage,tough fracture in section and no skin-core structure,and possessed the curing effect equal to that of conventional cured phenolic fibers.