硼酸凝固浴对MF-PVA纤维结构与性能的影响

Effect of boric acid coagulation bath on structure and properties of MF-PVA fiber

以三聚氰胺(M)、甲醛(F)、聚乙烯醇(PVA)水溶液为原料反应制得纺丝原液,经湿法纺丝得到三聚氰胺甲醛-聚乙烯醇(MF-PVA)纤维。研究了在凝固浴中加入硼酸对MF-PVA纤维结构及性能的影响。采用凯氏定氮法、扫描电子显微镜、单纤电子强力仪和极限氧指数(LOI)仪表征了纺丝过程氮流失率、纤维形貌结构、力学性能以及阻燃性能。结果表明:在凝固浴中加入硼酸可以有效地控制MF树脂的溶出,随着硼酸添加量的增加,纤维的氮流失率明显降低,断裂强度增加,断裂伸长率减小,LOI提高。当添加硼酸的质量分数为7%时,纤维的氮流失率只有14.64%,其LOI达到40%,但纤维表面变得粗糙。

Melamine formaldehyde-polyvinyl alcohol （MF-PVA） fiber was prepared by wet spinning process from the spinning dope concluding melamine （ M）, formaldehyde （F） and polyvinly alcohol aqueous solution. The effect of the addition of boric acid into coagulation bath on the structure and properties of MF-PVA fiber was studied. The nitrogen loss rate during the spinning process and the morphology structure, mechanical properties and flame retardance of the fiber were characterized with Gerhardt Kjeldahl determination device, scanning electron microscope, single fiber electronic tensile strength tester and limiting oxygen in- dex （ LOI ） apparatus. The results showed that the addition of boric acid into the coagulation bath can efficiently restrain the dis- solution of MF resin. The nigrogen loss rate of the fiber profoundly reduced, the breaking strength rose, the elongation at break dropped and the LOI value increased as the amount of boric acid was increased. The nitrogen loss rate was 14.64% and the LOI value reached 40% as the mass fraction of boric acid was 7%. But the surface of the fiber became rough.