聚乙烯醇/纤维素复合气凝胶材料的制备及其声学性能

Preparation of Lightweight Polyvinyl Alcohol/cellulose Composite Aerogel Materials with Sound Absorption Properties

利用绿色溶剂NaOH/尿素水溶液溶解微晶纤维素,引入交联剂环氧氯丙烷,通过溶胶-凝胶法将聚乙烯醇(PVA)均匀分散在纤维素溶液中。最后,通过冷冻干燥法,制得复合纤维素气凝胶。研究了PVA的含量对纤维素气凝胶骨架密度、孔隙率间的关系,分析了PVA含量及厚度对样品吸声性能的影响。结果表明,随着PVA的加入增多,样品内部孔强度得以提升;当纤维素与PVA比为3:2时,吸声系数最高可达到0.95以上;随着样品厚度的增加,样品吸声系数最高峰向较低频移动,2000 Hz后的吸声系数略有下降,但平均吸声系数仍在0.6以上。

Microcrystalline cellulose was dissolved in the green solvent NaOH/urea aqueous solution.The cross-linker epichlorohydrin was introduced and polyvinyl alcohol(PVA)was uniformly dispersed in the cellulose solution by the sol-gel method.Finally,the composite cellulose aerogel was produced by freeze-drying method.The relationship between the content of PVA on the skeleton density and porosity of the cellulose aerogel was investigated,and the effect of PVA content and thickness on the acoustic performance of the samples was analysed.The results showed that with the addition of PVA,the internal pore strength of the samples increased;when the ratio of cellulose to PVA was 3:2,the highest absorption coefficient could reach above 0.95;with the increase of the thickness of the samples,the highest peak of the absorption coefficient of the samples moved to lower frequencies,and the absorption coefficient after 2000 Hz decreased slightly,but the average absorption coefficient was still above 0.6.