Studies On The Components And Properties Of Casein Grafted Fibers Before And After Non-normal Treatments

Studies on the components and properties of casein grafted fibers before and after non-normal treatmentscasein grafted fiber is a kind of regenerated protein fiber,and belongs to modified acrylonitrile fibers.The components of fiber include graft polymer Casein-g-PAN,which is the most important element, multipolymer PAN and dissociative Casein.The fiber had excellent silky luster and cashmere-like soft hand feeling and cotton-like comfort due to the exist of casein,and which improved the properties of hygroscopic and dyeing without the deterioration of mechanical property.The stability of Casein component and the properties of the casein grafted fibers are studied mainly in this paper.This thesis includes three parts:(1)the solvent dissolving,hydrolyzing and IR spectrum analyzing are united to employ on the components of the fiber and graft ratio mensuration of casein grafted polymer.(2)Based on the above research,the components and graft ratio of four kinds of different casein grafted fibers were mensurated by experiments.And the same time,the basic properties,the influences of different casein content on the performance of grafted fibers were introduced.(3)The stability of four different fibers,which include the loss of casein and the effect of basic properties,were studied before and after non-normal treatments(different temperature,various concentration of acid and alkali solutions). The methods to mensurate the fiber components and the graft ratio, which is simple and accurate relatively,were determined in this paper.The results showed that the grafted casein fiber is a mixture of three different things,which includes Casein-g-AN,PAN and casein.With the increase of casein content,the stress of the fiber is enhanced in some degree,the properties of hygroscopicity and dyeing are enhanced significantly.But the formability was weakened with exorbitant casein content.The colors of fibers gradually changed into yellow under the temperature of 140℃,due to the thermal oxidative decomposition of casein.So the more casein content in the fiber,the more the colors changed.And the grafted casein fibers were sensitive to temperature especially on mechanical property.The effects of alkali treatment to the fibers were serious,especially the pH value is over 12, because which made the all casein content reduced and caused the decrease of basic properties.The effects of acid treatment to the fibers were faint, even the pH value is under 1.55,and the properties of hygroscopicity and dyeing are enhanced in some degree.So it's better for the finishing process of casein grafted fibers to be treated in acid solutions,rather than alkali solutions.In summary,the effects of alkali treatment to the fibers were badly,when the pH value reached a certain number,the ratio of casein in the fiber would be decreased,all kinds of properties showed reduce.The effects of acid treatment to the fibers were less than alkali,but more concentration made the components and properties destroy fainly.The colors of fibers gradually changed into yellow when the treat tempreture is too high.So,during the actual production and finishing process,the casein grafted fibers should be avoided from the high temperature and concentrated alkali,otherwise the performance deterioration would effect the normal use of the casein grafted fibers.