Preparation Of Sulfonyl-2-Hydroxypropyl Starch Size And Study On Its Size Film Properties

In order to improve the performance of starch in the field of textile sizing,starch modification is usually used to improve its sizing performance.A series of sulfonyl-2-hydroxypropyl starch with different degree of substitution were prepared by using sodium 3-chloro-2-hydroxypropyl sulfonate as etherifying agent.The synthesized starch was characterized by IR and SEM.The influence of reaction parameters on the degree of substitution of sulfonyl-2-hydroxypropyl starch was studied.The size film performance of sulfonyl-2-hydroxypropyl starch slurry and the properties of blend pulp membrane of polyvinyl alcohol and sulfonyl-2-hydroxypropyl starch were evaluated.The sizing properties of sulfonyl-2-hydroxypropyl starch and polyvinyl alcohol blended sizing for pure cotton yarn and polyester-cotton blended yarn were investigated.First of all,the technological parameters of the modification reaction have an important influence on the degree of substitution.When the reaction time,the concentration of starch emulsion and the amount of etherifying agent increased gradually,the degree of substitution increased gradually,and then increased to a certain extent,then gradually tended to smooth.When the reaction temperature and pH increased gradually,the degree of substitution increased first and then decreased.The results showed that when the reaction time was 7 h,the reaction temperature was 45 ℃,the pH value of the system was 11.5,and the concentration of starch milk was 40%,it was the best technological parameter for the synthesis of sulfonyl-2-hydroxypropyl starch.Secondly,the size performance of sulfonyl-2-hydroxypropyl starch a(HPSS)was studied and compared with that of acid-hydrolyzed starch(HS).The results showed that the breaking strength of HPSS was smaller than that of HS,the elongation at break was higher,and the hygroscopicity of HPSS was better than that of HS.The solution time is shorter than that of HS.Thirdly,the properties of sulfonyl-2-hydroxypropyl starch(HPSS)and polyvinyl alcohol(PVA)blend pulp membranes were studied.The results showed that after blending HPSS and PVA,the breaking strength of the slurry film decreased,the elongation at break increased obviously,and the toughness was also enhanced.With the increase of the degree of alcoholysis of PVA,the smaller the breaking strength,the longer the elongation at break,the greater the degree of polymerization of PVA,the greater the breaking strength and elongation of the serous film.The increase of degree of alcoholysis and degree of polymerization would lead to decrease of hygroscopicity and increase of water solubility time.With the increase of the blending ratio of PVA,the elongation at break of the PVA/HPSS composite film increased significantly,the fracture strength decreased and the toughness increased.When the blending ratio of PVA increased,the moisture absorption rate decreased gradually,and the water-soluble time was shorter.The slurry film prepared by HPSS and PVA 1799 at 60:40 mass ratio has better performance in all aspects,which can effectively improve the performance of the slurry film.At last,the sizing experiment of pure cotton yarn and polyester cotton blended yarn was carried out by using HPSS and PVA 1799 as sizing agent with the mass ratio of 60:40.The results showed that the hairiness index of the two yarns was significantly improved after sizing,and the hairiness reduction rate of more than 3 cm was basically 100%.The moisture regain of both yarns before sizing is lower than that after sizing.After sizing,the strengthening rate of cotton yarn is 16.97%,the elongation reduction rate is 27.97%,and that of polyester-cotton blended yarn is 7.2%and 16.07%respectively.The wear-resistant increase rate of cotton yarn is 2.45 times,and that of polyester-cotton blended yarn is 1.18 times.Through the sem picture,it can be seen that the yarn surface hairiness and defects are obviously reduced after sizing,and the yarn surface can also see a layer of serous film.Inside the yarn,you can also see the dip in the slurry and the closer entanglement between the fibers.