溶胶-凝胶法改性阻燃粘胶纤维的制备及其性能

为提升粘胶/二硫代焦磷酸酯(VF/DDPS)纤维的阻燃性能,通过溶胶-凝胶法,采用正硅酸四乙酯(TEOS)对VF/DDPS纤维表面进行阻燃改性,得到阻燃粘胶纤维(VF/DDPS/TEOS)。借助扫描电子显微镜、X射线光电子能谱仪、热重分析仪、锥形量热仪、微型量热仪、单纤强力仪等对改性纤维的结构和性能进行分析。结果表明:改性后VF/DDPS/TEOS纤维的阻燃性能提高,其在750 ℃时的残炭量从3.23%增加到7.93%,引燃时间从4 s延长至16 s,热释放速率峰值和总热释放量分别下降了19.3%和16.0%,极限氧指数从28.2%升高至29.3%;VF/DDPS/TEOS纤维表面形成了致密的氧化硅保护膜,二氧化硅在纤维燃烧过程中显著增强了纤维表面炭层的热质阻隔作用;阻燃整理后纤维的断裂强度、断裂伸长率及吸湿性能均有所降低。

Preparation and properties of sol-gel modified flame retardant viscose fiber

In order to improve the flame-retardant properties of viscose/dithiopyrophosphate(VF/DDPS)fibers,the sol-gel technology was used to modify the VF/DDPS fiber surface via the hydrolysis of tetraethyl orthosilicate(TEOS).The structures and properties of the modified flame retardant viscose fibers(VF/DDPS/TEOS)were characterized by means of scanning electron microscope,X-ray photoelectron spectroscopy,thermogravimetric analyzer,cone calorimeter,micro combustion calorimeter,and single fiber strength analyzer.The results show that the flame retardancy of VF/DDPS/TEOS fiber was improved with the increase of char residues from 3.23%to 7.93%at 750℃.Moreover,the ignition time of VF/DDPS/TEOS fiber is extended from 4 s to 16 s,peak heat release rate and total heat release are decreased by 19.3%and 16.0%respectively,and limiting oxygen index is increased from 28.2%to 29.3%.The surface of VF/DDPS/TEOS fibers forms a dense silica protective film,and the silica significantly enhances the thermal and mass barrier of the carbon layer on the fiber surface during combustion.However,the breaking strength,elongation at break and hygroscopicity of the modified fiber are decreased.