Study On The Pretreatment Processes And Performances Of Flax Fiber

Flax fiber is animportant material with excellent air permeability,moisture absorption and perspiration.Flax fiber obtained from the original stem through retting and hacking,it is stiff and length is uneven,also has high content of impurities.All the indexes between single fiber have a lot of discretenese,leading to the poor fiber spinnability.And because the original molecular orientation and crystallinity is high,and fiber also contains impurities such as lignin and hemicellulose,so the pretreatment technology of flax fiber is particularly important.Because the effect of sodium hypochlorite on lignin removal was good,so the pretreatment of flax fiber commonly used acid pickling?sodium chlorite bleaching?hydrogen peroxide bleaching process.However,in the sodium chlorite bleaching process will release chlorine dioxide gas,which is harmful to the health of the staff,the equipment of the corrosion and the pollution of the environment.At the same time,although the price of sodium silicate is low,the product whiteness is better,sodium silicate as an oxygen bleaching stabilizer in oxygen bleaching stage can easy to form "Silicon scale",deposited on the fiber and equipment,resulting in decreased fiber quality,equipment cleaning difficulties.And the above process consume time and energy.Therefore,it is urgent to improve the pretreatment process.In this paper,we explored the process of acid pickling?alkali oxygen one bath and enzyme pretreatment?one bath process of alkaline oxygen,and adopted orthogonal experiment to find the best technological formula of two kinds of processes.At the same time,according to the oxygen bleaching process with non silicon oxygen bleaching stabilizer including phosphorus stabilizer,silica sol,anionic polyacrylamide?PAM?and magnesium chloride,two ethylene three five amino methylene phosphonic acid?DTPMPA?and magnesium chloride,magnesium chloride and compound of DTPMPA and PAM and self-made poly acrylic acid magnesium salt?PAA-Mg?to replace the sodium silicate,to explore its application in flax bleaching process,and ensure oxygen bleaching process formula of different stabilizers.The following conclusions:The treated fiber whiteness,capillary effect,degree of polymerization as the fiber performance index,the optimal process of acid pickling?alkali oxygen one bath alkali oxygen one bath?owf?:H₂O₂ 12.8%,NaOH 10.4%,scouring agent GT 4.8%,Na2SO3 2.4%,sodium silicate 4.8%,bath ratio 1:8,90?,60 min,the fiber whiteness value is about 65.58,capillary effect value is about 16.4cm/30 min,the degree of polymerization is 2818.The optimum enzyme pretreatment?alkali oxygen one bath alkali oxygen one bath?owf?:H₂O₂ 11.2%,NaOH 10.4%,scouring agent GT 4.8%,Na2SO3 2.4%,sodium silicate 4.8%,bath ratio 1:8,90?,60 min,the fiber whiteness value is about 66.54,capillary effect value is 15.7cm/30 min,the degree of polymerization is 2809.The the best formula of oxygen bleaching with PAA-Mg as stabilizer is:PAA-Mg 1.6%,H₂O₂ 2.6%,pH=11.7,JFC 1.0%,Na₂CO₃ 1.9%.The the best formula of oxygen bleaching with DTPMPA as stabilizer is:pH=11.0,DTPMPA 1.8%,MgCl₂ 0.1%,H₂O₂ 2.6%,JFC 1.0%,Na₂CO₃ 1.9%.The the best formula of oxygen bleaching with PAM as stabilizer is:pH=11.0,PAM 8.0%,MgCl₂ 0.6%,H₂O₂ 2.6%,JFC 1.0%,Na₂CO₃ 1.9%.Silica sol as the stabilizer of the optimum bleaching process formula is:pH=11.0,silica sol 5.0%,H₂O₂ 2.6%,JFC 1.0%,and Na₂CO₃ 1.9%.The optimum formula of phosphorus stabilizer as oxygen bleaching stabilizer is:pH=11.0,phosphorus concentration of stabilizer is 1.6%,H₂O₂ 2.6%.DTPMPA and PAM mixture as stabilizer of the best oxygen bleaching process formula: H₂O₂ 2.6%,JFC 1.0%,Na₂CO₃ 1.9%,pH=11.0,DTPMPA 0.8%,PAM 5.0%,MgCl₂ 0.1%.Experiments show that non silicone type oxygen bleaching stabilizer can replace sodium silicate to a certain extent,and it can be used in the process of flax fiber oxygen bleaching.