微纤化程度对MFC气凝胶的性质和包装性能的影响

目的 深入研究制备过程中微纤化程度对微纤化纤维素（MFC）气凝胶的性质及导热、保温、缓释等性能的影响。根据相应性能数据将该气凝胶应用于包装领域，解决精油在包装内释放速率过快而造成精油浓度过高和短时间内消耗完毕的问题。方法 采用TEMPO(2,2,6,6-四甲基哌啶-1-氧自由基)/NaBr/NaClO氧化体系预处理针叶木漂白硫酸盐浆，通过改变高压均质次数和低温真空冷冻干工艺制备不同微纤化程度的MFC气凝胶，利用FT-IR、XRD、SEM和BET等技术分析气凝胶的结构性质，运用应力-应变测试、导热系数测试、TGA测试和GC-MS分析等方法分别对气凝胶的压缩、保温、耐热和缓释性能进行研究。结果 随着微纤化程度的增加，MFC气凝胶的结晶度逐渐增加，气凝胶的比表面积呈现先减小后增加的趋势，范围为17.643～35.171m2/g；气凝胶的压缩强度呈现增加趋势，增幅为15.35%；均质次数为10的气凝胶的耐热性最好，均质次数为8的气凝胶次之。结论 均质次数的增加引起MFC微纤化程度提高，不同微纤化程度的MFC气凝胶具有不同的内部结构性质，以及压缩、保温、耐热和精油负载缓释性能。

Effects of Microfibrillation Degree on Properties and Packaging Performance of MFC Aerogel

The work aims to research the effects of the homogenization times (microfibrillation degree of fibrous) during the preparation of microfibrillated cellulose (MFC) aerogels on the structural properties and other performances of MFC aerogels such as heat conduction, heat preservation, and sustained-release of antibacterial essential oil, and to solve the problems that the concentration of essential oil is too high and the essential oil is consumed in a short time due to the rapid release rate of essential oil in the package. The TEMPO/NaBr/NaClO oxidation system was used to pretreat softwood bleached kraft pulp. MFCs were prepared by high-pressure homogenization by changing the times of homogenization and followed by low-temperature vacuum freeze-drying to prepare MFC aerogels. FT-IR, XRD, SEM and BET techniques were used to analyze the structural properties of aerogels, and methods such as stress-strain testing, thermal conductivity testing, TGA testing and GC-MS analysis were used to analyze the compression, heat preservation, and thermal insulation of aerogels. The results indicated that the crystallinity increased with the increase of microfibrillation degree of fibrous. The specific surface area between 17.643-35.171 m2/g of MFC aerogels first decreased and then increased. With the increase of homogenization times, the compressive strength of aerogels showed an increasing trend with an increase of 15.35%. The MFC aerogel with 10 homogenization times had the best heat resistance, followed by the MFC aerogel with 8 times of homogenization. The increase of homogenization times causes an increase in microfibrillation degree of fibrous. MFC aerogels with different degrees of microfibrillation have different internal structural properties and performances of compression, heat preservation, heat resistance and essential oil loading and sustained release.