Study On Preparation Of Bamboo-based Dissolving Pulp By A Pre-impregnation KP Process And Its Anti-bacterial Modification

Bamboo is one of the richest resources in China, which can produce dissolving pulp. Developing and studying on this new textile fibers could be a new way of utilization of bamboo. At the same time, the properties of bamboo, such as green environmental friendly, antibacterial and other outstanding features, make it to be a substitute for cotton, hemp fiber. This paper based on neosinocalamus affinis which can produce fibers as a new raw material, using white and black liquid-immersed, low temperature and low alkali charge preparation of bamboo KP, and paste properties under two kinds of technology, carrying out a comparative study, identifying optimum conditions of a white liquid prepreg KP method and a black liquor prepreg KP pulping. After bleaching and purification treatment, the best way of preparation of qualified bamboo pulp was found out, and its antibacterial properties were analyzed. By oxidation grafted modification of Chitosan and initiated modification of Chitosan, the best modification of bamboo pulp preparation process conditions were determined, and two kinds of tests on the modification of bamboo pulp, Escherichia coli and Staphylococcus aureus, for detection of antimicrobial properties, got excellent results.By a comparative study of bamboo in white liquid prepreg KP pulping method and black liquor KP pulping method, it was found that using NaOH prepreg at high temperature before KP pulping, both potassium permanganate value and degree of polymerization can be greatly reduced. And Alpha-Cellulose content was more than91%, which was greatly conducive to subsequent bleaching and purification. At the same time, the white liquid prepreg KP optimum technological conditions for preparation of bamboo pulp was that:prepreg time30min, alkali content of10%, ABS (penetrant) of1.75%, cooking with alkali content of18%(in Na2O), curing degree of20%. And the black liquor prepreg KP optimum technological conditions for preparation of bamboo pulp was that: black liquid dilution with one time, adding alkali to content of10%.With D-E-D bleaching processes of the two pulps, the study found out that an appropriate increase in the amount of total available chlorine and alkali concentration can improve the whiteness and alpha-cellulose content of the two kinds of pulp. White liquor prepreg KP pulp had a better bleachability and can increase alpha-cellulose content easily. The acid treatment can reduce the ash content, increase whiteness, and at the same amount of acid, adding sodium hexametaphosphate to a certain extent helped to improve the whiteness. Using2%H2SO4,0.6%sodium hexametaphosphate as the best acid treatment, with the use of black liquor prepreg KP pulp method, bamboo pulp was obtained in a-cellulose content of92.65%under optimal conditions, with the average degree of polymerization of536. It was more obvious antibacterial than the conventional KP bamboo pulp, especially in antimicrobial resistance of E. coli of70.9%.Using two different methods to bamboo pulp for grafting modification of Chitosan, the first one was the use of periodate selective oxidation of bamboo pulp, and then grafted Chitosan, preparing the antibacterial bamboo pulp material of Chitosan grafted oxidation (CCF). During the preparation of bamboo pulp process, the oxidant concentration, time and temperature conditions had significant influence on aldehyde content of oxidation bamboo pulp. Its optimum conditions:①The best technological conditions of preparation of bamboo pulp:NaIO4of20g/L,5h oxide time, oxidation temperature40℃.②The best condition for grafted oxidation of Chitosan technology of bamboo pulp:concentration of Chitosan10g/L,2h grafting time, temperature of40℃. The second method used redox system consisting of K2S2O8and Na2S2O3as initiator, without using crosslinker, directly initiating Chitosan antibacterial materials of bamboo pulp to prepare Chitosan initiated bamboo pulp (CGF). Optimum technological conditions for the preparation of CGF: concentration of Chitosan2g/L,4h grafting time, temperature of45℃. Two methods effectively solved the problem of ’chemical fiber’, which was brought about by traditional modification of chemical crosslinker, and made it possible to prepare green antibacterial bamboo pulp.Using analysis of infrared spectroscopy, Ⅹ-diffraction, scanning electron microscope on two kinds of bamboo pulp samples, the study showed that with two methods of grafting modification, Chitosan and bamboo pulp had chemistry connections, but fiber change of crystal structure was not found, remaining cellulose Ⅰ. After the modification of Chitosan, the surface morphology of fiber had a significant change, fiber surface became rough, and there was a clear adsorbed section. Its antibacterial properties had also been made a lot of improvements; with antibacterial properties of Escherichia coli more of99%.It was considered that, using neosinocalamus affinis by black liquid prepreg of low alkali content KP pulping, and then bleaching and purification, can produce qualified bamboo pulp, which had very high production values in practical application. By Chitosan grafted oxidation and by Chitosan grafted initiating, bamboo pulp can obtain good antibacterial properties, which could have reference value on preparation of antibacterial textiles.