Relationship between the structure and thermophysical property of a starch-synthetic polymer composite under heated and pressurized conditions

利用农业衍生产品，如淀粉和替代完全合成的聚合物，减少了我们对石油化学衍生单体的依赖，并且由于这些植物衍生材料的生物降解性，目前是一个活跃的研究领域。获取热物理性质等基础数据对于设计和优化生产此类材料的设备非常重要。对淀粉-合成聚合物复合材料在加热和加压条件下的导热性能进行了测试，得到了以下结论：1)测量材料导热系数探头的研制基于瞬态热丝法的食品材料在加热（- 150 C）和加压（- 20mpa）条件下的导热系数探头已经研制成功。2)淀粉凝胶热导率的测定，通过实验验证了探针测得的数据的有效性，并与已发表的水的数据进行了比较，测定了凝胶化马铃薯淀粉在25-80‰、50- 80%含水量、0.2-10 MPa条件下的热导率。结果表明，淀粉凝胶的导热系数随温度和含水量的增加而增大，当压力达到1 MPa时导热系数增大，大于1 MPa时导热系数基本保持不变。通过考虑在制备过程中可能渗透到样品中的捕获细气泡的存在，可以证明压力依赖性是合理的。3)淀粉-合成聚合物复合材料的导热性能测定采用硝酸铈铵引发的丙烯酸甲酯在颗粒状玉米淀粉上聚合制备的淀粉-接枝聚甲基丙烯酸甲酯的导热性能，测试了其在20-80℃、7-35%水分、0.2-8 MPa条件下的导热性能。研究发现，导热系数随温度和含水量的增加而增加，尽管温度依赖性很小。此外，由于与2)相同的原因，导热系数随压力而增加。少

Use of agriculturally derived products such as starch and replacement for totally synthetic polymers reduce our dependence on petrochemically derived monomers, and are currently an active research area because of the biodegradability of these plant-derived materials, It is important to acquire the fundamental data such as the thermophysical properties for the design and optimization of the apparatus to produce such materials, In the present work, the thermal conductivity of a starch-synthetic polymer composite was measured under heated and pressurized conditions, and the following conclusions were obtained.1) Development of the probe to measure thermal conductivity of the materialThe probe for thermal conductivity measurement of food materials under heated (- 150ﾟC) and pressurized conditions (-20MPa) has been developed, being based on the transient hot wire method.2) Thermal conductivity measurement of starch gelAfter the validity of the data measured using the probe was verified by c … More omparison with published data of water, the thermal conductivity of gelatinized potato starches was determined at 25-80ﾟC, 50-80 % moisture, and 0.2-10 MPa. It was found that the thermal conductivity of the starch gel increases with temperature and moisture content, and that it increases with pressure up to I MPa, above which it remains almost constant. The pressure dependency can be justified by considering the presence of entrapped fine air bubbles which could have penetrated into the sample during the preparation process.3) Thermal conductivity measurement of starch-synthetic polymer compositeThe thermal conductivity of starch-graft-poly(methylacrylate), which was prepared by ceric ammoniumnitrate-initiated polymerization of methylacrylate onto granular corn starch, was determined at 20-80ﾟC, 7-35%moisture and 0.2-8 MPa. It was found that the thermal conductivity increases with temperature and moisture content, although the temperature dependency is so small. Also, the thermal conductivity increases with pressure due to the same reason as 2). Less