| A biodegradable starch/Polycaprolactone(PCL)-urethane plastic was studied in this paper. In the work , starch was grafting-modified and the starch-plastic was prepared.The grafting of polycaprolcatone on starch by ring-opening polymerization of e -caprolactone was initiated from the starch hydroxyl functions in the presence of a catalyst such as stannous octoate (Sn(0ct)2), Dibutyltin dilaurate(DBTDL) or titanium tetrabutoxide. The grafting ration could reach 16%. IR, X-ray diffraction and DSC were used to investigate the grafting-polymer. The effects of catalyst, reaction temperature and time, solvent and impurities in the reaction system on grafting were discussed.Polycaprolactone-urethane with cyanate group has been synthesised by low molecular PCL dio with toluene diisocynate(TDI). Then non-grafting starch or modifying starch was mixed with Polycaprolactone-urethane. Non-grafting starch and Polycaprolactone-urethane formed plastic with chemical reaction. Effects of prereaction of PCL and TDI and other main factors on material abilities were studied. The effects of conditions of samples-molding and post-treatment were also discussed. Starch-plastic with 70% starch content has a Tensile strength reaching 9. 5Mpa , and a Young's modulus higher than 290MPa. And the ability of material resistance to water has been improved obviously. Physical mixture was the main mechanism in the processing of starch plastic with modified-starch and Polycaprolactone-urethane. Modified starch has better compatibility with PCL, and the effects of some factors such as grafting ration of modified-starch on material abilities were investigated.Biodegradation experiment was carried out with siol-burying method. The result showed that the marterial appeared biodegaration in a short period. |
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