醋酸纤维素/SiO_(2)纳米纤维复合气凝胶的制备及性能研究

Preparation and Properties of Cellulose Acetate/Silicon Dioxide Nanofiber Composite Aerogel

以醋酸纤维素(CA)为原料,引入封闭水性异氰酸酯(BIC)与双马来酰亚胺树脂(BMI)双重交联,通过静电纺丝制备得到CA/BMI/BIC纳米纤维;将SiO_(2)纳米纤维作为无机增强相添加至CA/BMI/BIC纳米纤维的分散液中,通过冷冻干燥技术和热处理工艺制备CA/BMI/BIC/SiO_(2)复合气凝胶(CBBSiNFA);探讨了SiO_(2)纳米纤维的添加量对于CBBSiNFA力学性能、隔热性能和阻燃性能的影响。实验结果表明:随着分散液中SiO_(2)纳米纤维添加量的逐渐增加,CBBSiNFA的压缩应力、比强度、导热系数和阻燃性能逐步提高;当SiO_(2)/CA/BMI/BIC纳米纤维的质量比由0.2增加至1.0后,CBBSiNFA在60%应变下的压缩应力由0.53 kPa提高至2.25 kPa,导热系数由29.00 mW/mK增加至31.02 mW/mK,且CBBSiNFA-1.0压缩循环1000次后杨氏模量与最大应力都保持在初始量的97%以上,塑性形变为9.6%;CBBSiNFA具有良好的力学可调控性、弹性、隔热以及阻燃性能。

CA/BMI/BIC nanofibers were electrospun from cellulose acetate(CA)with the incorporation of blocked waterborne isocyanate(BIC)and double crosslinking using bismaleimide resin(BMI).SiO_(2)nanofibers were introduced into the dispersion of CA/BMI/BIC nanofibers as an inorganic reinforcement phase.Subsequently,the CA/BMI/BIC/SiO_(2)composite aerogel(CBBSiNFA)was fabricated through freeze-drying technology followed by heat treatment.The impact of SiO_(2)nanofiber addition on the mechanical properties,thermal insulation properties,and flame retardancy of CBBSiNFA was systematically investigated.The results revealed a progressive enhancement in compressive stress,specific strength,thermal conductivity,and flame retardant performance of CBBSiNFA with an increasing amount of SiO_(2)nanofibers.As the mass ratio of SiO_(2)/CA/BMI/BIC nanofibers increased from 0.2 to 1.0,the compressive stress at 60%strain for CBBSiNFA increased from 0.53 kPa to 2.25 kPa.Simultaneously,the thermal conductivity rose from 29.00 mW/mK to 31.02 mW/mK.Remarkably,even after undergoing 1000 compression cycles,the Young's modulus and maximum stress of CBBSiNFA-1.0 retained over 97%of their initial values,exhibiting a plastic deformation of 9.6%.Overall,CBBSiNFA demonstrated favorable mechanical controllability,elasticity,thermal insulation properties,and flame retardant.