The absorption behavior of chitosan in alkaline solution by freeze-blasting was studied.The influence of alkaline type,concentration,and small molecules was investigated,as well as the different roles of LiOH and NaOH...The absorption behavior of chitosan in alkaline solution by freeze-blasting was studied.The influence of alkaline type,concentration,and small molecules was investigated,as well as the different roles of LiOH and NaOH in the absorption.Chitosan reached its maximum absorption rate when LiOH concentration was 4.8 wt%and NaOH 4.0 wt%,respectively.Chitosan showed better absorption capacity in LiOH solution.Urea could improve the absorption when its concentration was more than or equal to 4.0 wt%,and the improvement was greater in NaOH solution.Thiourea showed no obvious effect in LiOH solution,but showed an effect when NaOH concentration was 4.0 wt%and 6.0 wt%.During the absorption,NaOH only reacted with-OH of chitosan,while LiOH not only reacted with-OH of chitosan,but also reacted with the acetyl group of chitosan.LiOH was more powerful in destroying hydrogen bonding of chitosan.LiOH/urea solution may be a uniquely powerful solvent for chitosan.展开更多
使用氢氧化钠-硫脲-尿素-水溶液预处理漂白阔叶木化学热磨机械浆,促进纤维之间的结合及纤维表面淀粉的留着以提高纸张强度。通过单因素实验,评估淀粉用量、纸浆浓度、用碱量、冷冻时间对纸张强度的影响情况并探究最佳工艺条件。当淀粉...使用氢氧化钠-硫脲-尿素-水溶液预处理漂白阔叶木化学热磨机械浆,促进纤维之间的结合及纤维表面淀粉的留着以提高纸张强度。通过单因素实验,评估淀粉用量、纸浆浓度、用碱量、冷冻时间对纸张强度的影响情况并探究最佳工艺条件。当淀粉用量为15%、纸浆浓度为15%、用碱量为7%、冷冻时间为45m i n时,该化机浆的增强效果最明显,在打浆度相当的前提下,成纸抗张指数、耐破指数都均较大提升,但耐折度没有明显变化。展开更多
文摘The absorption behavior of chitosan in alkaline solution by freeze-blasting was studied.The influence of alkaline type,concentration,and small molecules was investigated,as well as the different roles of LiOH and NaOH in the absorption.Chitosan reached its maximum absorption rate when LiOH concentration was 4.8 wt%and NaOH 4.0 wt%,respectively.Chitosan showed better absorption capacity in LiOH solution.Urea could improve the absorption when its concentration was more than or equal to 4.0 wt%,and the improvement was greater in NaOH solution.Thiourea showed no obvious effect in LiOH solution,but showed an effect when NaOH concentration was 4.0 wt%and 6.0 wt%.During the absorption,NaOH only reacted with-OH of chitosan,while LiOH not only reacted with-OH of chitosan,but also reacted with the acetyl group of chitosan.LiOH was more powerful in destroying hydrogen bonding of chitosan.LiOH/urea solution may be a uniquely powerful solvent for chitosan.
文摘使用氢氧化钠-硫脲-尿素-水溶液预处理漂白阔叶木化学热磨机械浆,促进纤维之间的结合及纤维表面淀粉的留着以提高纸张强度。通过单因素实验,评估淀粉用量、纸浆浓度、用碱量、冷冻时间对纸张强度的影响情况并探究最佳工艺条件。当淀粉用量为15%、纸浆浓度为15%、用碱量为7%、冷冻时间为45m i n时,该化机浆的增强效果最明显,在打浆度相当的前提下,成纸抗张指数、耐破指数都均较大提升,但耐折度没有明显变化。
