Study On The Preparation And Application Of Low-Gelatinization-Temperature Starch Adhesive

Starch adhesive is a kind of pollution-free functional adhesives,which is widely used in many fields.The key process of the production is starch gelatinization,traditional gelatinization requires a high-temperature reaction condition,resulting in a huge energy consumption.In this study,a low-temperature gelatinization technology of starch was designed,with wheat starch as raw material and alkali as gelatinization agent.Based on this technique,a new formula of the starch adhesive was prepared,with improvement of water resistance,corrosion resistance and bonding property.Then,the starch adhesive was applied into production process of three-layer eucalyptus plywood,and the technique of plywood was optimized.Main research contents are introduced as follows.Study on low-gelatinization-temperature technology of starch:Alkali was used as the main gelatinization agent and the low-temperature gelatinization technique of starch was explored through the single-factor method.The conditions are listed as follows:The mass of starch is 25g with a concentration of 8%,the dosage of NaOH solution is 3 5mL with a fraction of 5%,the dosage of paste accelerator is 25g,and the reaction time is 40min.Under these conditions,the gelatinization temperature of starch was only 36? and the viscosity was better.By means of XRD,SEM,FT-IR,TG-DTA and other characterization methods,the mechanism of starch gelatinization temperature reduction can be explained as:With alkali as the main gelatinization agent,the crystal structure of starch molecules are easily destroyed to exposed groups inside,and the synergistic effect of gelatinization agent and alkali is conducive to further damage to the internal structure of starch,which makes the starch gelatinization temperature is further reduced.The preparation of low-gelatinization-temperature starch adhesive:Dosage of the waterproof agent,preservative and self-made modifier was found through the experiment.The experimental results show that the dosage of waterproof agent Y was 0.2%,the dosage of preservative B was 0.8%,and the dosage of self-made modifier B was about 10%.In this condition,the water resistance of starch adhesives was improved more than double of what under the condition without water proofing agent,and the anti-corrosion time can reach more than 25 days.When it was applied to three-layer Eucalyptus plywood,the dry bonding strength and wet bonding strength reached 1.57MPa and 0.64MPa respectively.The comprehensive performance has been greatly improved.The application of low-gelatinization-temperature starch adhesive:In order to optimize the plywood production process,single-factor method was used with the application of low-temperature gelatinization starch adhesive.The results show that when the glue amount is 250g/m2,the aging time and pre-pressuring time is 2h and 60min,and the pressure,temperature and time of hot-pressing is 1.5MPa,110? and 9min respectively,the dry bonding strength and wet bonding strength of the three-layer plywood reaches 1.84MPa and 0.87MPa respectively,which means the bonding strength of the plywood made by starch adhesive with low-temperature gelatinization technique is satisfactory.Based on the results,the low-temperature gelatinization technology with wheat starch as main materials shows a good effect and great application value.Research on the preparation of starch adhesive and its application has great significance of saving energy and reducing consumption.So its application prospects will be very broad.