微晶纤维素的溶解及其阻燃性能

Dissolution and Flame Retardancy of Microcrystalline Cellulose in [CmVIM]Cl/TBAC

摘要:

以氯代1-氨甲酰甲基-3-乙烯基咪唑离子液体[CmVIM]Cl和四丁基氯化铵（TBAC）为溶剂，溶解微晶纤维素（MCC），加入不同阻燃剂三聚氰胺磷酸酯（MP）、聚磷酸铵（APP）、纳米二氧化硅（SiO2），制得阻燃纤维复合材料。通过偏光显微镜观察MCC的溶解过程，并利用FT-IR、XRD、TGA和SEM对再生MCC的结构、结晶度、热稳定性和形貌变化进行了表征。通过垂直燃烧实验、极限氧指数法（LOI）和热重分析法对阻燃性能进行测试。结果表明，溶解温度为90 ℃，TBAC的含量为8%，在溶解25 min时MCC的溶解率达6.3%，聚合度降至505；MCC部分结晶结构转为无定型结构，结晶度由74.0%降至46.4%；热分解温度由310 ℃降至262 ℃，最大失重率由2.6%/min降至1.4%/min。MCC表面由光滑平整的棒状结构转为凹凸不平的不规则结构。当m(MP)：m(APP)：m(SiO2)=1∶2∶2时，阻燃纤维复合材料的极限氧指数值提升至33.5%，垂直燃烧等级为V-0。

Abstract:

Use chlorinated 1-carbamoylmethyl-3-vinyl imidazole ionic liquid [CmVIM]Cl and tetrabutylammonium chloride (TBAC) as solvents to dissolve microcrystalline cellulose (MCC) and add different flame retardants melamine phosphate (MP), ammonium polyphosphate (APP) and nano-silica (SiO2) are used to prepare flame retardant fiber composite materials. The dissolution process of MCC was observed by polarizing microscope, and the structure, crystallinity, thermal stability and morphology change of regenerated MCC were characterized by FT-IR, XRD, TGA and SEM.The flame retardancy was tested by vertical combustion test, limiting oxygen index (LOI) and thermogravimetric analysis. The results showed that the dissolution temperature was 90 ℃, the content of TBAC was 8%, the dissolution rate of MCC was up to 6.3%, and the degree of polymerization was reduced to 505 when the solution was 25 min. MCC fractional crystallization structure into the amorphous structure, the crystallinity decreased from 74.0% to 46.4%; The thermal decomposition temperature decreased from 310 ℃ to 262 ℃, and the maximum weight loss rate decreased from 2.6%/min to 1.4%/min.The MCC surface changed from smooth and flat rod structure to uneven irregular structure. When m(MP)：m(APP)：m(SiO2)=1∶2∶2, the limiting oxygen index (LOI) of the flame retardant fiber composite increases to 33.5%, and the vertical combustion level is V-0.