Effect And Mechanism Of The CMC/CTAB Dual Strengthening System

In the papermaking industry, the material is various and the waste paper increases year by year, but non-wood resource still possesses apart of proportion. As the low strength of the material whose fiber is short, the application of paper reinforcing agent draws a extensive attention. Single reinforcing agent is difficult to meet the reinforced requirements of various material. It need to develop a series of dual strengthening system . Combining two reinforcing agent with multi-effect, utilizing their synergistic effect , the system will acquire marked effect and good economic, social and environmental benefit,at the same time,it will enjoy wide application prospec[0]t。In this thesis ,alkyltrimethylammonium bromides(CTAB) and carboxymethyl cellulose(CMC)form a dual strengthening system. By using technology of addition in pulp,the research compares the impact of CMC and CTAB with different alkyl group and pH of the solution to the paper strengthen[0]. Further more ,the optimum technological parameters were achieved and the mechanism of the dual strengthening system are discussed.The experiment results show that:the water retention value of the pulp increase with adding CMC , and the water adsorption and swelling capability of fiber are improved. Alkyltrimethylammonium bromides are cationic surfactants,they can significantly decrease the surface tension and strongly attach on the fiber to reduce the requiring of cationic charge .Moreover, the addition and fiber are distributed more uniform. The application effect is markedly improved by cooperating CMC and small amount of alkyltrimethylammonium bromides. Cetyltrimethylammonium bromide(CTAB) is the best one to cooperate with CMC. With the increasing of the CMC and CTAB dosage, the properties of sheet are increased .The properties of the sheet from bagasse chemical pulp get the best results with CMC dosage0.5%,CTAB dosage 0.1%, and pH 7. The tensile index ,burst index and tear index of the sheet are increased about 58.7%,58.95,35.9%,respectively.The results of scanning electron microscopy prove that : there are many"rope-like"bridges formed between the fibers in the dual strengthening system of CMC/CTAB. It can explain why the bonding force of the fiber increase by added the reinforcing agent.On the other hand,IR results show that : CMC and CTAB are adsorbed on the surface of the fiber, and the hydrogen bond formed with fibers improve the bonding force of the fiber.