Preparation and Properties of Cellulose Acetate/Silicon Dioxide Nanofiber Composite Aerogel
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).SiO2 nanofibers were introduced into the dispersion of CA/BMI/BIC nanofibers as an inorganic reinforcement phase.Subsequently,the CA/BMI/BIC/SiO2 composite aerogel(CBBSiNFA)was fabricated through freeze-drying technology followed by heat treatment.The impact of SiO2 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 SiO2 nanofibers.As the mass ratio of SiO2/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 1 000 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.
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