Preparation Of Blend Fiber Of Enzyme Modified Casein And Polyvinyl Alcohol

Natural fiber has low yield and high price,and the by-products of animal husbandry and planting industry also pollute the environment to a certain extent.The mass production of chemical fiber materials will inevitably lead to a large consumption of petroleum resources,and at the same time bring environmental pollution and other problems.Regenerated protein fiber is the hotspot and key direction of current research.It can turn waste into treasure,and achieve the purpose of reducing waste of resources and reducing pollution while obtaining good fibers.Pure regenerated protein spinning is more difficult,and the fiber strength is not high.At present,most of the regenerated protein fiber processes still use chemical crosslinking agents that are not easy to remove.In view of the above two problems,we modified the casein with enzymes to achieve the purpose of pre-crosslinking in order to increase the spinnability and strength of the fiber,and then mix with polyvinyl alcohol to increase the stretchability.In this experiment,the difference between before and after modification of casein was explored by means of infrared and SDS-PAGE electrophoresis,and the interaction and compatibility of casein and polyvinyl alcohol were studied by methods such as isothermal titration and optical microscope observation.The stretching ratio and breaking strength of the composite fiber obtained by the ratio of the original solution of different proportions,the 10%modified casein and 5% polyvinyl alcohol composite fiber have a higher stretching ratio of 2.67 times and the highest breaking strength of 25.598 Mpa.Observation of the morphological structure under the optical fiber microscope found that the modified casein fiber will form more lines,which is conducive to the moisture absorption and air permeability of the fiber.Then we used 10% modified casein/5% polyvinyl alcohol composite stock solution as the research object to study the influence of the pH and temperature of the spinning stock solution on its viscosity,compatibility,fiber stretching ratio,breaking strength,and morphological structure.Impact.The results showed that as the temperature increased,the viscosity showed a downward trend and the compatibility became better.The composite fiber of the spinning dope at 40-50? had a higher draw ratio of 2.28 times and a maximum breaking strength of 24.365 Mpa.The viscosity first increased and then decreased with the increase of pH,and reached the maximum at pH 9,and the maximum stretching ratio and maximum breaking strength appeared at the same time.Morphological observation revealed that the fiber thickness was uniform at pH 9 and the surface had lines.In the case of determining the ratio of casein/polyvinyl alcohol,the temperature and pH of the spinning dope,the influence of the different ratio and temperature of the coagulation bath on the spinning fiber was studied.It was found that the stretch ratio and breaking strength of the fiber spun under the conditions of 0.5% HCl,3% Ca Cl2,and 50% ethanol were 2.28 times and24.365 Mpa,respectively.The temperature of the coagulation bath has little effect on fiber formation.The fiber obtained by using enzyme-modified casein as the raw material shows superior performance,and the morphological structure is more conducive to the moisture absorption and heat absorption of the fiber.The addition of polyvinyl alcohol greatly increases the stretchability and flexibility of the mixed fiber,and the morphology and structure are more uniform.