Study On The Structrue And Dyeing Properties Of Casein Modified Polyacrylonitrile Fiber

The elemental analysis,FT-IR spectroscopy,SEM,X-ray diffraction,DSC-TG analysis were used to study the chemical composition and structure.It was found that configuration of milk protein fiber is round,with little holes in its cross section and grooves in its surface.It was composed of milk protein and acrylonitrile;the crystaUinity was 39.22%;this fiber had low hygroscopicity,and the thermal cracking began at 253℃and reached its peak at 322.4℃.Study on a series of its resistance to chemical agent found that its acid-resistance was good,but its alkali-resistance was bad.It was steadier in NaHCO₃ than other alkali reagent;it was very stable in H₂O₂ and Na₂S₂O₄ solution,but easily changing its color in the NaClO oxidant solution.In terms of the dyeing properties of milk protein fiber,three major classes of dyes, including acid dyes,reactive dyes and cationic dyes,exhibited good dyeing performance, but the dyeing conditions of these dyes were different.Milk protein fibers were dyed with acid dyes.The results showed that,the pH value was different with the dye changing,the more suitable dyeing pH value of weak acid dyes and acid dyes special for wool was 4～5,but that of the strong acid dyes was 2～3;the better dyeing temperature was 90～100℃,dyeing time was 60min.The milk protein fiber was dyed by purified weak acid dyes,showed that the beginning dye-uptake was large; the half-dyeing time was short;the dyeing rate curve at 90℃ascended first,then dropped; the adsorption isotherm is Nernst type.Milk protein fibers were dyed with reactive dyes.The results showed that the optimum dyeing process of the X,K type and the middle temperature reactive dye,could be chosen as pH value 4～5,dyeing time 60min,dyeing temperature 40℃,90℃,60℃, respectively,sodium bicarbonate 10～20g/L.Adding alkali reagent,its fastness to soaping increased from 3～4 to 4,and sodium bicarbonate had better fixing effects than sodium carbonate does.Study on the dyeing properties of cationic dyes on milk protein fiber,showed that the more suitable dyeing pH value of cationic dyes was 5～6,the better dyeing temperature was around 90℃,dyeing time was about 60min;electrolyte(NaCl) acted as retarding reagent.Its fastness to soaping was 3 or above 3.