Abstract
Cold reserving material is commonly used in the area of food transportation to preserve its low temperature and its freshness. A solvent is mainly water or salt solution. By adding around 2wt% of gel into the solvent, separation of the solvent and dispersion of the solvent in a moment of breaking the container can be prevented. However, mixing of gel suppresses the speed of solidification. Hence in this report, various types of sodium Carboxy Methyl Cellulose (CMC) were selected as cold reserving material, and influence of various parameters such as concentration, kinematic viscosity, degree of polymerization, degree of etherification on the speed of solidification were investigated. As a result, it was found with the based on the same concentration that the lower degree of polymerization gives higher speed of solidification. This is because size of the CMC molecules differs by the degree of polymerization, and the ability to eliminate CMC by freeze concentration changes. Based on the same kinematic viscosity, it was found that higher degree of etherification give higher speed of solidification, especially at low concentration. This is because of a hydrophilic phenomenon, and crystal can grow easily along CMC molecules.
