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Preparation And Low-temperature Sizing Properties Of Maleate Starch Derivatives

Posted on:2016-02-19Degree:DoctorType:Dissertation
Country:ChinaCandidate:W LiFull Text:PDF
GTID:1221330482964969Subject:Textile Engineering
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Natural starch has some drawbacks such as poor adhesion, film brittleness, and bad tensile properties of its film. More serious problem is that starch paste is prone to ageing at low temperature, leading to a lower adhesion-to-fiber and further decreased tensile properties of starch film, and thus the starch can not be used for low-temperature sizing. In order to overcome these shortcomings, a series of starch derivatives were prepared via maleation-containing starch derivatization. Effects of the derivatization on the paste ageing of starch and tensile properties of its film were investigated. And the adhesion of starch derivatives to fibers at low temperatures was evaluated.Firstly, a series of maleated starch(MS) with different degrees of substitution(DS) were synthesized via the maleation of acid-thinned starch(ATS) with maleic anhydride(MA). The effect of starch maleation on the paste ageing was estimated. In addition, the influences of DS value and paste temperature on the apparent viscosity and viscosity stability of cooked MS paste, adhesion-to-fiber, and tensile properties of MS film were also investigated. The experimental results showed that starch maleation can ameliorate the adhesion of starch to viscose fibers at low temperature. With the increases in DS values, the adhesion raised gradually. And with the decrease in paste temperature, the decrement in the adhesion was reduced. In addition, starch maleation improved paste stability. When DS value of MS was 0.04, the maleation could improve the adhesion effectively in the temperature range of 50~65oC. The maleation reduced paste ageing, thereby effectively alleviating the adverse impact of paste ageing on the elongation at break, flex-fatigue resistance of starch film, improving the tensile properties of starch film. With the increases in DS values, tensile strength of MS film and time required to break the film gradually decreased, whereas elongation at break, flex-fatigue resistance and moisture regain continuously increased. As paste temperature reduced, the alleviation of starch maleation on the adverse impact enhanced, and thus displaying high increment in the elongation.Secondly, in order to further improve the end-use ability of starch, sulfosuccinylated starch(SSS) was prepared via sulfonation of MS with sodium hydrogen sulfite(SHS). Influences of starch sulfosuccination on the adhesion-to-fiber at low temperature and tensile properties of starch film were investigated. The results showed that, compared with maleation, starch sulfosuccination further alleviated paste ageing, improved the adhesion at low temperature, and diminished the adverse effect of paste ageing on the elongation at break, flex-fatigue resistance of starch film. Therefore, the appropriate DS value and temperature were 0.036 and 60 oC, respectively.Thirdly, overcoming the adverse impact of electrostatic repulsion between anionic SSS and fibers on the adhesion for further improving the adhesion of starch to fibers, the synthesis of quaternized and sulfosuccinylated starch(QSS) was performed via starch quaternization and sulfosuccination. The impacts of ζ potential and modification level on the adhesion-to-fiber, desizability and film properties of starch were investigated. The experimental results showed that starch quaternization and sulfosuccination mitigated the negative effects: sulfosuccination on the adhesion and quaternization on the desizability. The adhesion and desizability of QSS was closely correlated with its ζ potential. Increase in the potential favored the adhesion, but disfavored the desizability. Electroneutral QSS not only had strong adhesion to viscose fibres, but also showed good desizability, taking account of the adhesion and desizability. Starch quaternization and sulfosuccination could ameliorate tensile properties of starch film. At the similar modification levels, ζ potential exhibited little influence on the tensile properties of QSS film, whereas the modification level displayed obvious effect on the film properties of QSS at electroneutrality condition. This observation confirmed that modification level was the main index of the factors that influenced the properties of QSS film.Fourthly, we also evaluated the adhesion of electroneutral QSS to cotton and viscose fibers at low temperature, and investigated the impact of paste ageing on the tensile properties of electroneutral QSS film. And the reason that starch had poor adhesion to cotton fibers at low temperature was also discussed. The results showed that the poor adhesion was mainly attributed to cotton wax distributed on the surface of cotton fibers and paste ageing, and thus the cotton warps must be dewaxed before low-temperature sizing. Electroneutral quaternization and sulfosuccination alleviated the ageing. Through alleviating the aging, the adverse effects of paste ageing on the adhesion-to-fiber and tensile properties of starch film were mitigated.Finally, to investigate the feasibility of maleate starch derivatives used for low-temperature sizing, electroneutral QSS was selected and performed the sizing experiment by means of ATS as control sample. The feasibility of electroneutral QSS used for low-temperature sizing was evaluated in terms of the increase in tensile strength, loss in elongation, abrasion resistance and decrease in hairiness, thereby laying a foundation for the application of maleate starch derivatives in warp sizing. The results showed that electroneutral QSS could be used for low-temperature sizing of viscose warps at 60 oC, and high increase in tensile strength, enhanced abrasion resistance, low loss in elongation and high decrease in hairiness were displayed.
Keywords/Search Tags:starch, paste ageing, maleation-containing derivatization, adhesion-to-fiber, tensile properties of starch film
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