醋化级芦苇溶解浆的制备及其性能

Preparation and characterization of acetate grade reed pulp

为探索使用可再生的芦苇资源制备醋化级溶解浆的可行性,以湖南洞庭湖区的南荻为原料,采用水预水解-硫酸盐法蒸煮-D_(0)E_(p)D_(1)(ClO_(2)漂白脱木素段-H_(2)O_(2)漂白段-ClO_(2)漂白增加白度段)3段漂白工艺制备了南荻浆粕,并对其甲种纤维素含量、白度、聚合度、多戊糖含量、灰分含量和铁含量,以及表观形貌、化学结构和晶体结构等进行测试与分析。结果表明:蒸煮后南荻的粗浆得率为46.31%,3段漂白工艺使南荻浆粕的主要性能指标得到明显改善,其甲种纤维素含量提高了1.24%达到97.70%,白度提高1倍达到91.42%,特性黏度降低38.01%,使南荻浆粕的平均聚合度达到1413;制浆过程中高温、NaOH、Na 2S、ClO_(2)和H_(2)O_(2)的共同作用使南荻中的木质素、半纤维素和灰分得到有效去除。本文工艺制备的南荻浆粕的性能达到了醋化级溶解浆的基本要求,为下一步制备醋酯纤维素和醋酯纤维提供参考。

Objective Based on the research on using biomass materials(such as bamboo,straw,sorghum straw,mulberry straw,hemp,bagasse,olive,tobacco stem and so on)to prepare acetate grade dissolving pulp and downstream products,this paper proposes the use of rich reed resources in Dongting Lake area to explore the feasibility of preparing acetate reed pulp,and test and analyze the performance of the prepared pulp so as to establish understanding on the preparation of cellulose acetate and acetate fiber.Method The typical sulfate method was adopted to prepare the Triarrhena lutarioriparia dissolving pulp.Firstly,the water pre-hydrolysis of Triarrhena lutarioriparia slices was carried out in an electrothermal high-pressure boiling pot(Fig.2)with a liquor ratio of 1∶4.Then,the equipment was used for sulfate boiling(Fig.3),where the main components of the boiling solution were NaOH and Na 2 S.Crude pulp was cleaned with a 45μm polyester mesh bag and sieved with a sieve machine with a sieve gap of 0.25 mm.Finally,the D_(0)E_(p)D_(1)three-stage bleaching process(Tab.2)was used for bleaching,and the bleaching agents were ClO_(2)and H_(2)O_(2).The cellulose I content,whiteness,polymerization degree,pentosan content,ash content and iron content of the prepared triarrhena lutarioriparia dissolving pulp were tested,and the apparent morphology,infrared spectroscopy,Raman spectroscopy and X-ray diffraction were employed for analysis.Results The yield of crude pulp after boiling was 46.31%.The three-stage bleaching process significantly improved the main performance indexes of Triarrhena lutarioriparia pulp.The content of cellulose I increased by 1.24%to 97.70%,the whiteness doubled to 91.42%,and the intrinsic viscosity decreased by 38.01%,which made the average degree of polymerization of pulp reach 1413.In addition,the pentosan content,ash content and iron content of the pulp after bleaching were 5.76%,0.004%and 0.000562%,respectively.The cellulose fibers prepared from Triarrhena lutarioriparia dissolving pulp were long cylindrical with rough surface showing a large number of grooves,cracks,pores and filaments.In the infrared spectra(Fig.5),the Triarrhena lutarioriparia dissolving pulp showed a typical cellulose characteristic peak,and the intensity of the absorption peak was enhanced compared with that of Triarrhena lutarioriparia.The characteristic peaks of lignin at 1254 cm-1 and 1511 cm-1 and the characteristic peaks of hemicellulose at 1726 cm-1 disappeared,indicating that the pulping process removed the lignin and hemicellulose in Triarrhena lutarioriparia.The characteristic peaks at 1169 cm-1 and 1607 cm-1 relating to lignin disappeared,and the intensity of the characteristic peak at 2896 cm-1 decreased indicating that non-cellulose substances such as lignin in Triarrhena lutarioriparia were removed during pulping(Fig.6).The Triarrhena lutarioriparia dissolving pulp showed a typical diffraction curve of cellulose I.The small peak at 26.4°disappeared and no peak appeared at 29.4°(Fig.7),suggesting that the inorganic components such as SiO_(2)in Triarrhena lutarioriparia were effectively removed after the pulping process.Conclusion The acetate grade Triarrhena lutarioriparia dissolving pulp was prepared by water pre-hydrolysis-sulfate cooking-D_(0)E_(p)D_(1)three-stage bleaching process.The combined action of high temperature and chemical agents during the pulping process effectively removed the lignin,hemicellulose and ash in Triarrhena lutarioriparia,formed irregular microfibril structure on the surface of cellulose fiber,and presented a rough surface full of grooves.The successful preparation of acetate grade Triarrhena lutarioriparia dissolving pulp not only lays a foundation for the preparation of cellulose acetate and acetate fiber,but also helps open up a new way for high-value and efficient utilization of reed resources.