Study On Oil/water-amphipathic Modified Starch With Quaternary Ammonium And Alkenylsuccinyl Substituents Used As Size Base Materials

As a textile sizing material,starch has a long history of being used.However,due to the defect of the structure of the original starch,the adhesion property to the synthetic fiber is poor,and the size film is fragile and stiff.To enhance the operation performance of the starch size,the method of starch modification is usually used to improve the sizing performance of the starch.Proceeding from the oil-water amphipathy structural design,the macromolecular chain of the starch is introduced with the hydrophilic quaternary ammonium cationic perssad and lipophilic alkyl succinate simultaneously to prepare a series of modified starches with oil-water amphipathy,so as to discuss the influences of alkyl succinate perssad structure as the lipophilic perssad,oil-water amphipathy functional group molar ratio and oil-water amphipathy modification degree on the adhesion property and sizing performance of the modified starch,assess the sizing performance of quaternary ammonium positive ion-alkyl succinate modified starch sizing with oil-water amphipathy,and investigate the sizing effect of using the modified starch to replace PVA in the sizing manufacturing process.First,the structure of the introduced lipophilic perssad is selected.A series of oil-water amphiphilic starches were prepared by introducing octenyl succinate group,dodecenyl succinate group and octadecenyl succinate group into starch macromolecule.The research result indicates that:under the condition of unchanged quaternary ammonium cationic group substitution degree,as the carbon chain length of the alkyl succinate decreasing,the viscosity of the starch increasing,the viscosity heat stability increasing,The mechanical properties of starch film were improved,and the abrasion of the size film decreased.In the quaternary ammonium positive ion-alkyl succinate starch with the same perssad structure,when the alkyl succinate substitution degree is high,the surface tension of the starch size is relatively small,and the adhesion property of the starch size to the fiber is good.In the introduced lipophilic substituent perssad structure,to choose the octenyl succinate with the relatively short carbon chain length proves the best choice.During the process of amphiphilic modification of starch with oil and water,the oleophilic substituent group was selected as the best one with shorter carbon chain length.Secondly,the paper studies the influences of oil-water amphipathy functional group molar ratio on the performance of the modified starch.Through changing the reagent volume of the hydrophilic and lipophilic substituent groups,a series of quaternary ammonium positive oinion-octenyl succinate starches with different oil-water amphipathy function group molar values were designed and prepared,so as to investigate the modified starches with different oil-water amphipathy function group molar values to the adhesion performance of the fiber,performance of the size film,and biological degradability of the starch,thus confirming the appropriate scope of the oil-water amphipathy function group molar values.The research results show that:after introducing the hydrophilic quaternary ammonium cationic perssad and lipophilic alkyl succinate simultaneously into the starch macromolecule,the prepared modified starch possesses the characteristics of oil-water amphipathy.Such an oil-water amphipathic modification method had effectively improved the adhesion performance of the starch and the performance of the size film.Such adhesion performance and size film performance change as the oil-water amphipathy function group molar value changes.The molar percentage of the lipophic substituent group in the total substituent group was P_o.As the P_o increasing,the viscosity of the quaternary ammonium positive ion-octenyl succinate oil-water amphiphilic starch gradually reducing and the viscosity stability reducing accordingly.The surface tension of the oil-water amphiphilic starch size first reduces and then increased.However,the adhesion strengths to the cotton fiber and polyester fiber increased at first and decreased next.When P_o was 70.6%,the adhesive strength of quaternary ammonium positive ion-octenyl succinate oil-water amphiphilic starch size to the fiber reaches the maximum.Compared with the acidolysis starch size film,the crystalline degree of the starch size film after being modified by the quaternary ammonium positive ion groups and octenyl succinate reduces,and the flexibility of the size film increased.As P_o increasing,the elongation at break and fracture work of oil-water amphipathic starch increasing first and then reduced.Compared to the acidolysis starch,the water solution time of the oil-water amphipathic starch size was short and the expansion rate increased,thus being beneficial for desizing of the starch size.When P_o was 52%,the elongation at break and fracture work of quaternary ammonium positive ion-octenyl succinate oil-water amphiphilic starch film reach the maximum.After comprehensively considering the above performances of the starch size,it can be seen that it was appropriate to value the oil-water amphipathy functional group molar value in 50%-70%in conducting oil-water amphiphilic modification.Thirdly,the influences of the oil-water amphipathy modification degree on starch performance was studied.Under a certain oil-water amphipathy functional group molar value,the influences of different oil-water amphipathy modification degrees to the adhesion performance and size film performance of the quaternary ammonium positive ion-octenyl succinate starch were investigated,and the BOD₅/COD value was used to analyze the influence of modification degree on the biological degradability of the starch,thus confirming the appropriate oil-water amphipathy modification degree of the quaternary ammonium positive ion-octenyl succinate starch.The research result showed that:as the oil-water amphipathy modification degree increasing,the reaction efficiency of both the hydrophilic substituent group and lipophilic subsituent group was reduced.When the substituent degree of the lipophilic subsituent group exceeded 0.036,the reaction efficiency reduced significantly,the surface tension of the starch size reduced,and the adhesion strengths of the starch size to cotton fiber and polyester fiber increased.When the modification degree was higher than0.051,as the modification degree increasing,the adhesive strength of the starch size to fiber increased insignificantly,the elongation at break and fracture work of the starch size increased,the size film becomes more flexible,the water solution time of the size film reduced,and the expansion rate increased,thus being beneficial for starch desizing.When the modification degree was higher than 0.051,the improvement in abrasive resistance and flexibility resistance of the starch sizing was not obvious.The starch was conducted with oil-water amphipathic modification by quaternary ammonium cationic group-octenyl succinate group,the biologic degradability of the starch declined.When the oil-water amphipathy modification degree was higher than 0.051,BOD₅/COD value was lower than 0.3,and the starch becomes not easy for biological degradability.After comprehensively considering the influence of the oil-water amphipathy modification degree on starch sizing performance,the modification degree of quaternary ammonium positive ion-octenyl succinate oil-water amphipathy modified starch was better to be in 0.026-0.051.Fourthly,the sizing performance of the oil-water amphipathic starch had been studied.Through conducting sizing test to polyester/cotton blending,the strengthening rate,elongation reducing rate,hairiness decrement rate and grinding increase rate had been investigated;and the desizing efficiency of the starch had been tested;the sizing performance of quaternary ammonium positive ion-octenyl succinate oil-water amphipathy modified starch had been assessed.The results show that the oil-water amphiphilic modification can significantly improve the sizing performance of polyester/cotton blended yarn.The sizing had high reinforcement,abrasion and hairiness reduction,low elongation reduction and high desizing efficiency.It can be seen that the application of this oily two affinity modified starch sizing agent in polyester/cotton sizing was feasible.In the end,the sizing manufacturing application of oil-water amphipathical starch had been investigated.In the practical manufacturing environment in the workshop,the quaternary ammonium positive ion-octenyl succinate oil-water amphipathy modified starch has been conducted with pilot scale production,and used for polyester cotton variety to replace PVA sizing production.The practical manufacturing results indicated that:the pilot scale production of oil-water amphiphilic starch was stable and smooth,and this starch modification method and its production process can be industrialized.By replacing PVA sizing with oil-water amphiphilic starch,the loom efficiency of this kind of starch was increased by 2.1 percentage points and the sizing cost was reduced by 0.03 yuan per meter.