工艺参数对淀粉/EVA复合发泡材料挤出发泡的影响

以淀粉和乙烯－醋酸乙烯酯（EVA）为原料制备生物质发泡材料的过程中,工艺参数对复合发泡材料的生产制备有着很大的影响.研究了在制备淀粉/EVA复合发泡材料过程中螺杆转速对塑化形态的影响,喂料速度对制备过程的影响,模口温度对泡孔大小的影响和原料含水率对材料膨胀率的影响.研究发现：螺杆转速设置为120 r/min时,淀粉/EVA复合材料挤出物塑化效果最优;适当的喂料速度,可避免“架桥”“堵塞”现象;模口温度设置为160 ℃时,可配合发泡剂达到充分分解,使泡孔最大化;当原料含水率为14%时,复合发泡材料的膨胀率达最大值,为14.4%.

Effects of Process Parameters on Extrusion Foaming ofStarch/EVA Foam Composite Materials

During the process of preparing the biomass foam materials with starch and EVA as raw materials, theprocess parameters have great influence on the preparation of foam composite materials. The effects of screw speed onplasticizing morphology, feeding rate on preparation process, extrusion die orifice temperature on bubble size and materialmoisture content on expansion rate were focused in research. The study showed that when the screw rotation speed was setat 120 r/min, the plasticizing effect of Starch/EVA composites extrusion foaming was optimal. Feeding speed would affectthe whole extrusion process. By adjusting the feeding speed, the“bridge”“blocked”phenomena could be avoided.When the die temperature was set to 160 ℃, with the complete resolving of foaming agent, the bubble could reach thecomplete maximization. Moisture content had a great influence on starch /EVA composite foaming material. When moisturecontent rate in raw materials was 14%, the swelling rate reached the maximum value of 14.4%.