Study On Modification Of Degradable Starch Water-based Adhesive

Starch adhesive, for its abundant resources and biodegradable property, is an environmental friendly industrial product that could be used in many fields. However, its application is limited by its bad water-resistance, slow drying speed and low fluidity. In order to improve these disadvantages of starch adhesive, this paper had studied on the modification of degradable starch water-based adhesive, which used potato starch as the raw material, H2O2 as the oxidant and PVA as the second modifying agent. The process could be separated into two parts: In the first part, taking into account influences of starch content, oxidant amount, temperature, reaction time and the pH value, starches were oxidized by L25(56) orthogonal experiments in low oxidation condition and high oxidation condition, respectively. And then, oxidized starch adhesives were prepared and the viscosity, water-loss ratio and water-resistance were tested. After that, the influencing factors on the properties of adhesives were discussed and optimized synthesis conditions for better viscosity, water-loss ratio and water-resistance of oxidized potato starches in both oxidation conditions were obtained. In the second part, the selected oxidized potato starches were modified by PVA and the results were discussed. After then, the relevant laws were summarized.The results of modification indicated that the orthogonal factors on the properties of oxidized potato starch adhesives showed different laws because of the different oxidation conditions. While the other conditions were the same, the solids content of starches in high oxidation degree, for their fierce degradable, were too low to get the water-resistance and water-loss ratio of the obtained oxidation starch adhesives worse than that obtained in low oxidation degree. However, due to their high oxidation degree, the polarity of starch molecules and the interaction between molecules were enhanced. When they were modified by PVA, the adhesives showed better stability and the properties were improved obviously. Thus potato starches in high oxidation degree were more suitable for the study of this paper and their modified products had achieved the purpose of improving the disadvantages of raw starch adhesives.