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以砌古城墙用的黏结剂之一糯米粉为原料,采用快速黏度分析仪(RVA)糊化淀粉,研究不同浓度、搅拌速率、搅拌时间和最高温度对糊化曲线的影响。结果表明:随着浓度的增加,最低黏度和峰值黏度与最终粘度相差越大,即衰减值和回生值分别增大,说明糨糊的稳定性差、冷却后凝胶性强。随着最高温度变高,峰值黏度升高,峰值时间减小;随着搅拌时间和速率的增加,最终黏度下降,说明剪切力影响其黏度。利用物性仪测试了不同陈化时间对成糊淀粉黏结力的影响。陈化时间越长,胶体不易凝集,形成清稀的胶状。糊化淀粉随陈化时间增加发生大分子链降解或重结晶等不同程度的老化,表现为剥离强度减小,粘附性下降。以上实验分析与研究给古城墙修复提供了理论依据。
The effect of different concentration, stirring rate, mixing time and maximum temperature on the gelatinization curve was studied by using glutinous rice flour, one of the adhesives used to build ancient city wall, as raw material. The results show that as the concentration increases, the difference between the minimum viscosity and the peak viscosity and the final viscosity is larger, that is, the attenuation value and the regenerated value increase respectively, indicating that the paste has poor stability and strong gel after cooling. As the maximum temperature increases, the peak viscosity increases and the peak time decreases. With the increase of stirring time and rate, the final viscosity decreases, which indicates that the shear force affects the viscosity. The effect of different aging time on the adhesive force of pasteurized starch was tested by physical property tester. The longer the aging time, the colloid is not easy to aggregate and form a clear and gummy shape. Gelatinized starch with aging time increases macromolecule chain degradation or recrystallization and other degrees of aging, the performance of the peel strength decreases, decreased adhesion. The above experimental analysis and research to provide a theoretical basis for ancient city wall repair.