【作者】 唐爱民；

【导师】 梁文芷；

【作者基本信息】 华南理工大学 ， 制浆造纸工程， 2000， 博士

【摘要】 本文用超声波对速生材木浆纤维为原料的纤维素纤维进行预处理以提高纤维素纤维的可及度和化学反应性能。首次从不同的结构层次较为系统地研究了超声波处理对纤维素纤维的形态结构、超分子结构、分子量及其分布的影响，并研究了超声波处理后纤维素纤维可及度的变化及其与超声处理条件的关系，考察了超声波处理对纤维素纤维与高碘酸盐发生选择性氧化反应的反应性能的影响，对超声波作用下纤维素纤维结构与性质的变化机理进行了初步探讨，主要研究内容和结论如下： 1 用多功能显微镜、扫描电镜(SEM)对超声波作用下纤维素纤维的形态结构和超微结构变化进行了表征，并用纤维长度测定仪测定纤维长度和粗度变化。研究结果表明，超声波处理后纤维素纤维的形态结构、超微结构发生了如下变化：细胞壁出现位移和变形、初生壁P层和S1层脱除、吸水润胀和S2层纤维的细纤维化。研究结果显示，超声波处理对纤维长度影响不大。 2 超声波作用下纤维形态结构和超微结构的变化程度与原料纤维本身的形态结构特征、纤维形态尺寸大小及超声处理条件如超声处理时间、功率有关。三种速生材木浆纤维素纤维原料中，桉木漂白硫酸盐浆EBKP纤维和马尾松漂白硫酸盐浆MBKP纤维在超声波的作用下，纤维形态结构和超微结构变化明显，而桉木预水解硫酸盐溶解级浆GCEP在超声波的作用下，形态结构和超微结构的变化不如前两种显著，不容易产生分丝帚化现象，但可观察到细胞壁层的脱除现象。随着处理时间和超声波功率的增大，纤维形态结构和超微结构变化程度增大。研究了超声波处理时浆浓度对超声效应的影响，研究确认超声波较处理适宜的浆浓度范围是1～3％。 3 用X-射线衍射分析结合傅利叶变换红外光谱，表征了超声波处理对纤维素结晶参数的影响，对超声波作用下纤维素超分子结构变化的机理进行了一些探讨。结果表明超声波处理后纤维素的晶区尺寸变化不大，但结晶度变化则与纤维形态结构尺寸、处理时间和超声波功率有关。不同原料来源的纤维素纤维，由于形态尺寸和超分子结构的差异，经超声波处理后超分子结构表现出不同的变化规律；超声波处理过程中，结晶和消晶两种作用同时存在：超声波功率对纤维素的结晶度有较大的影响，对晶体尺寸有一定程度的影响，但结晶度Xc与超声功率没有线性关系：在频率为23-25 kHz，功率为400W条件下，对桉木漂白浆纤维进行超更多还原

【Abstract】 Ultrasonic wave has been applied in the pretreatment of the fast-growing wood pulp cellulose fibers in order to increase the accessibility and reactivity of cellulose. A systematic study in different structure levels has originally been made on the changes of the morphology, supermolecular structure, and molecular weight and its distribution of cellulose brought about by ultrasonic treatment The accessibility of the cellulose fibers after it had been treated with ultrasonic characterized as water retention value and surface area has also been investigated. The selectively oxidation reactivity of the treated cellulose fibers with sodium periodic has been studied in detail. The tentative mechanism for the changes in structure and properties of cellulose fibers resulting from the ultrasonic treatment has been discussed. The main research aspects are as follows:1. The morphology and fine structure of cellulose fibers treated with ultrasonic have been characterized by polarized light microscopy and scanning electron microscopic observation. The fiber length and coarseness are analyzed. The results showed that the morphology and the fine structure of cellulose fibers have changed during the ultrasonic treatment. Rupture and removal of the P and S1 layer, dislocations in the S2 layer, swelling of the fiber, and then fibrillation in the S2 layer have been observed on ultrasonic treated cellulose fibers. It is showed that ultrasonic treatment has less effect on fiber length.2. The level of changes on fibers’ morphology and fine structure is dependent on the raw fibers’ morphology size and the ultrasonic treatment conditions such as treatment time, consistency of the slurry, and the power of ultrasonic wave. The experimental results on morphology and fine structure of the treated cellulose fibers indicate that (1) the morphology structure of bleached masson pine (MBKP) and eucalyptus Kraft pulp (EBKP) fiber is readily changed by ultrasonic treatment, and (2) the eucalyptus dissolving pulp (GCEP) cellulose fiber is more resistant to the ultrasonic treatment As the treatment time and ultrasonic power increased, the effectiveness of the treatment increases and there is a significant increase in fibrillation. The proper更多还原