Study On The Effect Of Shearing Principle On The Synthetical Properties Of Starch Size

The film-forming properties of macromolecule polymeric compound-starch size which is usedin sizing yarn and strong mechno-chemistry function caused by high speed shearing , are researchedin this subject. The influence of high shearing mechanical treatment on the technologicalfilm-forming properties of macromolecule polymeric compound-starch size are also studied.Firstly the rheological property, film-forming mechanism and the critical index of the influenceon film-forming properties have been analyzed in my thesis;the lubricating-approximate model(LAM) of the shearing process is established by means of Viscous Flow settled for the"lubricating-approximation" principle. And the theoretical shearing rate model on the starch size isalso conducted.Secondly, based on the shearing rate model, the distribution and transformation status of thecircumferential and radial flow velocity field and pressure field in turbulent flow field is researched.The average shearing rate of the whole flow field is calculated based on the theoretical research inorder to guide the experiments leading towards a right way.Moreover, the experiments which consists of the effect of high shearing on the film-formingproperties of polymeric compound original starch size paste was studied by means of the repeatableOrthogonal experiment. The amylose content, molecule weight, the viscosity of size paste, the heatstability of viscosity, adhesion behaviors and mechanical behaviors etc are determined, thesemeteyard and criteria on size film properties are entirely evaluated. The experimental resultsindicate that changes are found on the chains of starch after conducting high shearing, which causesa modification in the properties of starch. The degrading effect of high shearing on starch agrees tothe common mechno-chemical degrading feature. The high shearing behavior breaks the side chainsof starch and eventually increases the amylose content in solution. Finally, the starch/PVA(polyvinyl alcohol) blend solution was experimented and the resultindicates that the dispersion of starch in PVA is improved by high shearing and the interactionbetween starch and PVA is strengthened, resulting in an improvement of the mechanical properties,transparency and water-repellence of starch/PVA blend film. By theoretical and experimentalresearch, it is proved that the high Shearing principle on improvement of starch size properties isscientific and practical. The results of the research can make guidance to the macromoleculepolymeric compound's buildup of the strength and ductility. This research affords a reliablereference and provides scientific basis for further development.