卡拉胶纤维的阻燃性能

以钡盐为凝固浴, 经湿法纺丝技术获得卡拉胶纤维(CAF). 通过极限氧指数(LOI)、 锥型量热(Cone)、 扫描电子显微镜(SEM)、 元素分析(EDS)、 X射线衍射(XRD)、 热重红外(TG-FTIR)同步差示扫描量热(DSC)法、 热裂解(Py)和气相色谱-质谱法(GC-MS)对CAF进行表征. 结果表明, CAF极限氧指数高达50以上, 锥型量热过程中, CAF一直保持红热状态, 没有产生火苗, 其热释放速率及总释放热等参数均较低, 与海藻酸钙纤维(ALF)和琼胶纤维(AGF)相比, CAF具有较好的阻燃性. 可能机理为卡拉胶分子的硫酸酯基和渗入纤维内部的钡离子发生络合作用, 并促进交联成炭和改变纤维裂解过程. 裂解过程中产生的磺酰自由基与燃烧产生的氢氧自由基迅速结合, 终止燃烧反应. 同时, CAF在燃烧过程中产生大量残炭, 并形成致密的钡盐结构层和中空的纤维结构, 成为CAF阻燃的另一重要因素.

Flame-retardant Property of Carrageenan Fiber†

Carrageenan fibers( CAFs) were obtained through the wet spinning technique with barium salt as coagulation bath. The fibers were characterized by limiting oxygen index(LOI), Cone calorimeter(Cone), scaning electron microscopy-energy dispersive spectrometer( SEM-EDS) , X-ray diffraction( XRD) , thermogravimetry( TG)-differential scanning calorimetry( DSC)-Fourier transform infrared spectroscopy( FTIR) and pyrolysis(Py)-gas chromatography(GC)-mass spectrometry(MS). The results showed that carrageenan fiber( CAF) took on better flame retardancy than calcium alginate fiber( ALF) and agar fiber( AGF) . The LOI of CAF was up to more than 50, and the fiber kept red state without flame in the whole Cone process. Some other Cone parameters presenting lower value, such as heat release rate, total heat release, indicated that CAF has good flame retardancy. The sulfate ester combined with barium ion through complexing action of CAF, and they played an important role in the formation of carbon residue and changing the breakup processes of carra-geenan macromolecule. In addition, flame-retardant mechanism could be attributed to sulfonyl free radical, which can combine with hydroxyl radicals rapidly to terminate the combustion reaction. Meanwhile, the dense structure of barium salt layer and hollow fiber structure were also crucial factors of flame retardant performance for CAF.