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为了替代以石油为原料的吸水材料,实验制备了2种以纸浆为原料的吸水材料。对未干燥的漂白硫酸盐浆,采用TEMPO-氧化后可引入新的羧基和醛基。研究发现,醛基有利于改善吸水材料湿状态下的强度,原因可能是形成了半缩醛结合,氧化后纸浆纤维逐渐分散。分析表明,分散速率随氧化剂用量的增加而增大。冷冻干燥可使物料具有多孔性的泡沫状结构,该结构具有较大的表面积。即使在一定的压力下,较大的表面积也可赋予物料较高的吸收速率和较好的吸收能力。风干干燥使物料形成一种具有较小吸收速率和较大吸收能力的压实薄层。
In order to replace the petroleum-based water-absorbing materials, two types of water-absorbing materials based on pulp were prepared experimentally. For undried bleached kraft pulp, new carboxyl and aldehyde groups can be introduced by TEMPO-oxidation. It was found that the aldehyde group is conducive to improving the strength of the water-absorbing material under wet conditions. The reason may be that the hemiacetal is formed and the pulp fibers gradually disperse after oxidation. Analysis shows that the dispersion rate increases with the amount of oxidizer. Freeze-drying allows the material to have a porous, foamy structure with a large surface area. Even under a certain pressure, the larger surface area can also give the material a higher absorption rate and better absorption capacity. Air-drying makes the material form a compacted thin layer with a lower absorption rate and greater absorbency.