Research On Improving The Water Absorption Of Kitchen Paper

In recent years,the market share of kitchen towel has grown rapidly,and the price of raw wood pulp,which is the mainstream raw material for the tissue paper market,has continued to raise,which has prompted domestic tissue companies to find altermative raw materials with cheap price and better performance.Bamboo fiber has the advantages of natural bacteriostasis,low price,and short growth cycle,it has become a rising start in the tissue paper products.However,the kitchen towels made from bamboo pulp has low water absorption and affects the final quality of the product.The technique of adding nanocellulose to improve the water absorption and other physical properties of the pulp was experimentally studied in this thesis,which has important theoretical and practical value for improving the performance of the pulp and the quality of the final products.In this thesis,high-yield and kraft bamboo pulp were used as the main raw materials to make kitchen towels.Firstly,the influence of the of bamboo pulp beating degree on the physical properties of kitchen towels was investigated.It was found that the beating progress of bamboo fiber promoted the improvement of the strength of kitchen towels.At the same time,as the beating degree futher increased,the water absorption of the base paper gradually decreased.When the beating degree of bamboo pulp fiber was 30°SR,the tensile index of the high yield bamboo pulp was 18.53 N·m/g and the water absorption was 6.80 g/g;the tensile index of the kraft bamboo pulp was 22.47 N·m/g,water absorption was 8.17 g/g.The optimum beating degree of the bamboo fibers was determined at 30°SR.The bamboo pulp fiber was pretreated with cellulase,and then used to make kitchen towels.The cellulase-pretreated bamboo pulp exhibited higher water retention values and higher water absorption behavior of the base paper by comparison with the untreated pulp and paper.When the amount of cellulase increased from 0.14 U/g to 0.70 U/g,the water retention value of the high yield bamboo pulp increased by 4.5%,the water retention value of the kraft bamboo pulp increased by 5.2%,and the base paper also showed higher water absorption performance.The water absorption of high yield bamboo pulp increased from 6.80 g/g to 8.79 g/g,and the water absorption of kraft bamboo pulp increased from 7.68 g/g to 9.03 g/g.More importantly,the strength properties of the base paper after cellulase treatment have also increased.The tensile strength of the high yield bamboo pulp increased 23.2%;the tensile strength of the kraft bamboo pulp increased 27.0%.Cellulose nanofibril(CNF)was mixed with the bamboo fibers pulp before paper-making process,to improve the water absorption behavior and mechanical properties of the base paper.CNF themselves possess large specific surface area and abundant hydroxyl groups as well,thus enhancing the hydrophilicity of tissue paper,and the CNF addition can form 3D structures in kitchen paper,thus providing abundant pores with uniform small size,which would facilitate the capillary effect for water absorption,and more hydrogen bonds formed between CNF and bamboo fibers,thus improving the strength properties of kitchen paper,thanks to the excellent mechanical and physical properties of CNF.When CNF content was 10%,the water retention value of the high yield bamboo pulp increased by 17.0%,the water retention value of the kraft bamboo pulp increased by 16.8%,and the base paper also showed higher water absorption performance.The water absorption of high yield bamboo pulp increased from 6.80 g/g to 8.69 g/g,and the water absorption of kraft bamboo pulp increased from 7.68 g/g to 9.41 g/g;the tensile strength of the high yield banboo pulp increased 32.3%;the tensile strength of the kraft bamboo pulp increased 24.7%.The results from the bulk and pore size analyses,FTIR,as well as SEM images of tissue paper also evidenced the conclusions above.Temperature and pH are the main factors affecting the water absorption behavior of kitchen paper.An increase in temperature causes water molecules permeate into the paper,thereby increasing the concentration of water molecules in the capillary.When the absorption time was 60 s,the water temperature increased from 20℃ to 80℃,and the water absorption of the paper increased from 3.50 g/g to 9.49 g/g,an increase of 2.71 times.With the increasing of pH,the swellability of the fiber was improved,and the surface area of the fiber increased,thereby improving the water absorption behavior of the paper.When the absorption time was 20 s,the pH increased from 4.23 to 10.22,and the water absorption of the base paper increased from 2.23 g/g to 2.56 g/g.