废弃三醋酸纤维素的回收再生及其相关性能研究.pdf

上海交通大学硕士学位论文 IV废弃三醋酸纤维素的回收再生及其相关性能研究废弃三醋酸纤维素的回收再生及其相关性能研究 摘摘 要要 醋酸纤维素酯是一类重要的生物质材料三醋酸纤维素（CTA）是指纤维素主链的葡萄糖单元上的三个羟基都被乙酰基取代，在商业上广泛应用的三醋酸纤维素的取代度一般要高于 2.7 三醋酸纤维素近年来主要作为偏光板的支持体，大量应用于制作液晶显示屏 LCD，代替长期以来一直应用的阴极射线管 CRT，由于其不产生对人体有害的射线，因而问世后大受欢迎，更因质量提高，生产技术成熟和成本下降，生产规模和市场发展极为迅速，优胜劣汰也很快因此，对废弃三醋酸纤维素薄膜的回收利用，将有助于环境的保护、废弃物资源的再生利用，所以该研究具有非常重要的社会和经济价值 在制备液晶屏的偏光板时，添加了各种助剂，如增塑剂、稳定剂和填充剂等本文着重选取了两种主要的增塑剂磷酸三苯酯（TPP）和邻苯二甲酸二丁酯（DBP） ，研究了上述两种添加剂对纯三醋酸纤维素水解特性和水解产物性质的影响，探讨了废弃三醋酸纤维素薄膜水解的机理，以期推动对三醋酸纤维素产品回收利用的工业化进程本文选取了在 50℃～70℃之间的水解环境进行研究，研究结果表明，增塑剂的存在将降低水解的效率；不过高含水量及长水解时间将有助于减缓这种影响。

因上海交通大学硕士学位论文 V此在有增塑剂 TPP 及 DBP 存在的环境下，采用以上两种方法来提高水解效率是切实有效的方法 此外，纤维素及其衍生物作为分离用膜材料，具有来源广泛、价格低廉、制膜工艺简单、成膜性能良好、成膜后选择性高、亲水性好、透水量大等优点纤维素类膜对水有良好的透过性，能有效去除血液中对人体有害的小分子物质如肌酐、尿素等，被成功应用于生物分离领域，如血液透析、过滤、渗透等 本文同时研究了通过紫外辐照的方法，在醋酸纤维膜的表面接枝上油酸；并研究了不同接枝条件如预辐照与否、不同光敏剂浓度、不同预辐照时间和不同接枝反应时间等条件对改性膜的结构性能的影响实验结果表明：以二苯甲酮（BP）为光敏剂，通过紫外辐照接枝聚合的方法可以在醋酸纤维素膜的表面引入不饱和脂肪酸油酸预辐照将提高膜的接枝率，预辐照的最佳时间为 20min通过调节紫外辐照时间，光敏剂的浓度，可以提高膜表面的接枝率，改善膜表面的亲水性能本实验中最佳的光敏剂浓度为 9％，最佳的接枝反应时间为 30min改性后的膜材其洗液的△pH 都小于 0.50，而 UV250-320几乎都小于 0.3，可见符合血液滤材的一般标准 关键词关键词：醋酸纤维素，水解，取代度，接枝改性，油酸，紫外辐照 上海交通大学硕士学位论文 VISTUDIES ON RECYCLE OF CELLULOSE TRIACETATE AND THE RELATED PERFORMANCES ABSTRACT Cellulose acetate represents a material with a wide range of application. The advantage of cellulose acetate lies in low toxicity, low or almost non-flammability. It is produced from renewable resources and is biodegradable at least after pretreatment. CTA is from natural material, cellulose, which is environmentally friendly. The CTA film has been widely used because of its superiorities in terms of relatively high moisture regain, significantly low birefringence, moderate mechanical strength and low production cost, which included photographic film, protective film for polarizing plate（PFPP）, and optical compensation film for liquid crystal display (LCD). Various additives are added to improve the processibility and the performance of the CTA products. These include the plasticizer, anti-block agents, band release agents, colorants etc. Of all these additives, plasticizer accounts for the biggest proportion. Although a range of plasticizers can be used, dibutyl phthalate (DBP) and triphenyl phosphate (TPP) have become two main choices, due to their 上海交通大学硕士学位论文 VIIhydrophobic nature, favorable environmental and health credentials. The film, containing these two kinds of plasticizers, results in excellent gloss and clarity, optimal physical properties, such as softness, strength and being food contact approved. Cellulose acetate has also been utilized in a variety of separation and purification processes. In membrane separation, cellulosics, in particular cellulose acetate, have played important roles. Hemodialysis and desalination are the established fields where acetate membranes have been applied. As Cellulose diacetate (CDA) is much more widely used than CTA and has a strong market potential, while the price of CDA is much more expensive than CTA, it is profitable to reclaim CDA from discarded CTA products. Herein, attempting to reclaim CDA from PFPP, we investigated CTA hydrolysis process with the existence of plasticizer. By simulating the hydrolysis process of PFPP, we hope to propel the industrial application of this aspect. Our works concerned the factors affecting the degree of substitution (DS) of CTA in hydrolysis process, including different plasticizers, plasticizer concentration, reaction time, water content and catalyst concentration. Analytical methods including FTIR and 1H-NMR were used to characterize the products. The results showed that plasticizer concentration would reduce 上海交通大学硕士学位论文 VIIIthe hydrolysis efficiency. High water content, longer reaction time and higher catalyst concentration were effective ways in decreasing the DS. But as high water content and longer reaction time would be beneficial in preventing degradation, while higher catalyst concentration brought in byproducts, the former two methods were recommended in hydrolysis process. In another aspect, we had studied the graft modification of CA membrane with oleic acid, anticipating its application in blood filtration and absorption of blood cells. The effects of the modification conditions, such as pre-irradiating time, initiator concentration and irradiating time were discussed. We also used FTIR-ATR, Contact Angle and SEM to characterize the modified CA membranes. Our results showed that pre-irradiation was beneficial in grafting; 20min and 30min were the optimal pre-irradiating time and irradiating time respectively. Benzophenone （BP）was acted as photo sensitizer and initiator; we found 9% was the appropriate concentration. The water absorption of the modified CA membrane was much better that of the CA membrane. The △pH and UV250-320 results of the modified CA membrane also meet the requirements of the clinical application, showing that these membranes could be used in blood treatment. KEY WORDS: KEY WORDS: CTA, Hydrolysis, DS，Graft, BP, Ol。