通过 TEMPO 氧化法从废弃丝瓜络中成功提取出纤维素纳米纤维(CNF)，并通过超临界二氧化碳(scCO2)发泡技术制备聚乙烯醇(PVA)/CNF复合发泡材料。对CNF在复合材料中的结晶性进行表征，探究了CNF含量对泡孔形貌的影响以及CNF含量对发泡材料收缩性能的影响。结果表明，CNF在发泡过程中可作为异相成核点，提高成核效率，减小了平均泡孔尺寸，增加了泡孔密度，同时减少了泡孔褶皱，降低了发泡材料的收缩率。当CNF含量为2%时，平均孔径从99。96 μm下降至41。96 μm，泡孔密度增加了大约一个数量级，收缩率从12。19%下降至5。02%。
Extraction of cellulose nanofibers from waste of loofah and application in polyvinyl alcohol supercritical carbon dioxide composite foams
Cellulose nanofibers(CNF)were successfully extracted from waste loofah by TEMPO oxidation,and polyvinyl alcohol(PVA)/CNF composite foam materials were prepared by supercritical carbon diox-ide(scCO2)foaming technology.The crystallinity of CNF in composites was characterized,and the influ-ence of CNF content on cell morphology and CNF content on shrinkage properties of foamed materials was explored.The result showed that CNF can be used as a heterogeneous nucleation point in the foaming process,which improves the nucleation efficiency,reduces the average cell size,increases the cell density,reduces the cell folds,and reduces the shrinkage rate of the foamed material.When the CNF content is 2%,the average pore size decreases from 99.96 μm to 41.96 μm,the cell density increases by about an order of magnitude,and the shrinkage rate decreases from 12.19%to 5.02%.
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