基于冷冻干燥法的淀粉基多孔材料制备与性能

以淀粉为主要原料、剑麻纤维为增强体、水为发泡剂、辅以甘油增塑剂，运用冷冻干燥法制备一种可全降解的环保多孔材料。对致孔机理进行了探究，理清了加工工艺流程，并对样品进行红外光谱分析（FTIR）、扫描电镜（SEM）表征及膨胀率测试。结果表明：相对于挤出法、注塑法多孔材料，冷冻干燥法多孔材料样品的泡孔尺寸较小，孔壁较厚；甘油、水和剑麻纤维的用量对淀粉基多孔材料的膨胀率存在一定的影响，随着剑麻纤维用量的提高，膨胀率逐渐增加，随着甘油及水用量的增加，膨胀率则先增大后减小；当淀粉用量为500 g时，剑麻纤维用量为250 g、甘油为200 g、水为250 g，膨胀率分别达到极大值。运用冷冻干燥法制备淀粉基多孔材料，可有效避免淀粉难以热熔加工的问题，工艺简单、设备成本低，可为淀粉基多孔材料在泡沫、凝胶等制品的实际生产提供新思路。

Preparation and Properties of Starch-Based Porous Materials by Freeze-Drying Method

The porous material is a fully degradable and environmentally friendly material prepared by freeze-drying, using starch as the main raw material, sisal fiber as the reinforcement, water as the foaming agent, and glycerol as the plasticizer. The porosity mechanism was explored, and the processing procedure was clarified. Through infrared spectroscopy analysis (FTIR), scanning electron microscope characterization (SEM) and expansion rate test of the samples, it was found that compared with the porous materials by extrusion and injection molding methods, the porous material samples by freeze-drying method had smaller cell size and thicker pore walls. The addition of glycerol, water and sisal fibers had an effect on the expansion rate of starch-based porous materials, the expansion rate gradually increased with the increase of sisal fibers dosage, and the expansion rate increased first and then decreased with the increase of glycerin and water dosage. When the dosage of starch was 500 g, 250 g of sisal fiber, 200 g of glycerol and 250 g of water were added, the expansion rate reached a maximum value respectively. Using the freeze-drying method to prepare starch-based porous materials can effectively avoid the problem that starch is difficult to hot melt. The process is simple and the equipment is cheap. It can provide a new idea for the practical production and application of starch-based porous materials in foam, gel and other products.