Study On Qctenyl Succinate-carboxymethyl Qil-water Amphiphilic Starch Size

Starch is one of the three main sizing material.However,the size film forming on yarn is hard and brittle,resulting in serious peeling,due to its rigid internal structure.At the same time,the adhesion property of starch sizing film forming on hydrophobic yarn fibers is poor,which is unable to meet the application requirements of the current production.From two views of chemical denaturing and physical blending,this article first introduced carboxymethyl hydrophilic groups and octenyl succinate lipophilic groups to modify the starch and obtained amphiphilic structures microscopically.Therefore,the adhesive strength between the modified starch and hydrophobic yarn fibers,and mechanical properties of the sizing film were improved synergically.Afterwards,the modified starch was blended with PVA to further improve the toughness of the film.In this paper,the effects of the molar ratio of oil-water amphiphilic functional groups and the modification degree on the viscosity,thermal stability,adhesive strength,and mechanical properties of the sizing were first studied to determine the optimal parameter range.The desizing performance and size film performance of the acid-hydrolyzed starch,quaternary ammonium cation-octenyl succinate starch,and octenyl succinate-carboxymethyl oil-water amphiphilic starch were evaluated.Finally,the octenyl Succinate-carboxymethyl oil-water amphiphilic starch was physically blended with PVA,and investigated the effect of PVA alcoholysis degree,polymerization degree and blending ratio on the properties of octenyl succinate-carboxymethyl oil-water amphiphilic starch/PVA blending,the results showed that:(1)As the molar ratio of oil-water functional groups increased,the viscosity and thermal stability of the octenyl succinate-carboxymethyl oil-water amphiphilic starch decreased;the adhesion to pure cotton fibers and polyester fibers increased first and then decreased,when the molar ratio of the functional groups of oil and water was 69.0%,the adhesion reached a maximum value,and at the same time,the surface tension also reached the minimum when the molar ratio was 69.0%.With the increased of the oil-water molar ratio,the breaking strength of the octenyl succinate-carboxymethyl oil-water amphiphilic starch sizing film increased gradually,and the breaking elongation increased first and then decreased,which was the maximum when the molar ratio was 48.4%.Based on the comprehensive experimental results,it was appropriate to select the molar ratio of the introduced oil-water functional groups between 48.4%and 69.0%.(2)As the modification degree increased,the reaction efficiency of the hydrophilic groups of octenyl succinate-carboxymethyl oil-water amphiphilic starch and lipophilic groups decreased;at the same time,the viscosity of the sizing and its thermal stability decreased slightly.With the modification degree increased,the surface tension of the sizing reduced and the adhesion to the fiber increased,but when the modification degree was greater than 0.049,the increase or decrease of the two is no longer obvious;the breaking elongation and breaking strength of the starch sizing film increased with the modification degree.Considering the properties of the sizing and the efficiency of preparation,it was appropriate to select the total modification degree of the oil-water functional group at 0.049.(3)By comparing the desizing performance of acid-hydrolyzed starch,quaternary ammonium cation-octenyl succinate starch,octenyl succinate-carboxymethyl oil-water amphiphilic starch,and the hygroscopicity of the sizing film capability,the desizing performance of octenyl succinate-carboxymethyl oil-water amphiphilic starch is the best,followed by acid hydrolysis starch,the desizing performance of quaternary ammonium cation-octenyl succinate starch was poor.At the same time,the hygroscopicity of the two oil-water amphiphilic starch sizing film was superior to acid-hydrolyzed starch,and the hygroscopic capacity of the two was not much different.(4)Under the control of the blending ratio,as the degree of PVA alcoholysis increased,the adhesion of the blended sizing material to cotton fibers increased,the adhesion to the polyester decreased,and the mechanical properties of the blended sizing film increased significantly.With the increased in the degree of polymerization,the adhesion of the blended sizing to the fiber first increased and then decreased,and the elongation at break of the blended sizing film first increased and then decreased,all reaching the maximum at 1700.The improvement effect of sizing performance was the best.In addition,as the blending ratio of PVA increases,the adhesive strength and elongation at break of the blended sizing increased,while the breaking strength decreased.