Research And Application On Long Chain Alkenyl Succinic Anhydride Modified Starch As Surface Sizing Agent

This paper discussed that a new type of starch surface sizing agents,which were synthesized by modifying various kinds of starches with alkenylsuccinic anhydride (ASA) in aqueous slurry systems to introduce thehydrophobic groups to starches. Effects of the reaction temperature, reagentratios, reaction time, catalyst (DMAP) and the effect of the sizing concentrationon the sizing effect were discussed to obtain the optimum synthetic process. Thestructure and properties of the products were determined by the fouriertransform infrared spectroscopy (FT-IR), x-ray diffraction (XRD), elementalanalyzer, search engines marketing(SEM), surface tension-meter and contactangle measurement. The main results were as follows:a ASA modified MS-1starch(1) Results indicated that the suitable parameters for the preparation wereas follows: reaction temperature was65℃, the mass ratio of MS-1starch toASA was5:1, the dosage of DMAP was4.5%amounting of MS-1starch,reaction period was2.0h.(2) FT-IR analyses characterized the structure of the products bycomparing MS-1starch and ASA modified MS-1starch, ASA modified MS-1starch had an absorption peak in1569cm-1while MS-1starch hasn’t, whichproved carbonyl existence in ASA modified MS-1starch and esterificationreaction happened between ASA and MS-1starch.(3) X-ray diffraction (XRD) analyses showed that the crystal structure ofMS-1starch and ASA modified MS-1starch did not change while crystallinitychanged. The crystallinity of ASA modified MS-1starch was26.76%while thecrystallinity of MS-1starch was40.30%. (4) Surface tension of different concentrations of solutions of the ASAmodified MS-1starch preparing by the optimal technical conditions wasdetermined. The critical micelle concentration (CMC) of solution of the ASAmodified MS-1starch was13g/L. The results showed that the solution of theASA modified MS-1starch had low surface tension, high surface activity andgood hydrophobic interaction.(5) The observation through the scanning electron microscopy (SEM)indicated that the ASA modified MS-1starch surface changed and had granularmaterial on its surface because of the esterification reaction while MS-1starchsurface was smooth. The original loosely woven fibers of the paper becamecloser. Most of the empty space of the fibers and fibers covered by sizing agentand the paper surface was covered with a continuous thin layer.(6) The sizing concentration5%was the optimal degree of sizing, when theoptimal technical conditions of the synthesis of ASA modified MS-1starchcould be adopted in surface sizing. The sizing degree could reach206s andcontact angle was133°. then, the tensile strength, folding strength and ringcrush index of paper sized, compared with the original paper, increased whilewhiteness declined.b Alkenyl succinic anhydride (ASA) modified AKD special starch(1) Results indicated that the suitable parameters for the preparation wereas follows: reaction temperature was55℃, the mass ratio of AKD specialstarch to ASA was4:1, the dosage of DMAP was4.5%amounting of MS-1starch, reaction period was2.0h.(2) FT-IR analyses characterized the structure of the products bycomparing AKD special starch and ASA modified AKD starch, ASA modifiedAKD starch has an absorption peak in1571cm-1while AKD special starch hasn’t,which proved carbonyl existence in ASA modified AKD starch andesterification reaction happened between ASA and AKD special starch.(3) X-ray diffraction (XRD) analysis showed that the crystal structure ofAKD special starch and ASA modified AKD starch did not change itscrystalline structure while crystallinity changed. The crystallinity of ASAmodified AKD starch was35.66%while the crystallinity of AKD special starchwas37.94%. (4) Surface tension of different concentrations of solutions of the ASAmodified AKD starch preparing by the optimal technical conditions wasdetermined. The critical micelle concentration (CMC) of solution of the ASAmodified AKD starch was7g/L. The results showed that the solution of the ASAmodified AKD starch had a lower surface tension, higher surface activity andbetter hydrophobic interaction.(5) The observation through the scanning electron microscopy (SEM)indicated that the ASA modified AKD starch surface changed and had granularmaterial on its surface because of the esterification reaction while AKD specialstarch surface was smooth. The original loosely woven fibers of the paperbecame closer. Most of the empty space of the fibers and fibers covered bysizing agent and the paper surface was covered with a continuous thin layer, inorder to enhance the waterproof function of the paper.(6) The application of surface sizing proved that under the optimaltechnical conditions of synthesis the ASA modified AKD starch could get theoptimal degree of sizing when the sizing concentration was5%. The sizingdegrees can reach72s and contact angle was127°. Tensile strength, foldingstrength and ring crush index of paper sized, compared with the original paper,increased while whiteness declined.