Influence of technological parameters on extrusion foaming of starch/EVA biologic materials and BP neural network forecast

During the preparation of biologic foam materials using starch and ethylene-vinyl acetate copolymer(EVA) as raw material to prepare the starch/EVA biologic materials, the influences of screw speed, die temperature and moisture content on extrusion foaming have been studied, and the double-layer BP network model based on artificial neural network technique has been built. The orthogonal experiment result has been used as samples to train and forecast the expansibility of biologic foam materials. The results show that this BP network model is effective to forecast expansibility of the starch/EVA biologic materials accurately, and the expansibility gradually increases with the increase of screw speed. When the screw speed is 320 r/min, expansibility reaches its maximum. The expansibility also increases with the rising of die temperature and reaches its maximum at 140℃. Moisture content also has significant influence on the expansibility of the starch/EVA foam materials.