synopsisThe changes in temperature and crystallinity of polymer during nonisothermal crystallization were theoretically analyzed assuming a cooling condition under which heat transfer occurs at a rate proportional to the difference in temperature between polymer and the,environment. When a plateau appears in the temperature change during crystallization, crystallization temperature can be predicted by a simple method. This method gives nearly the same value as that obtained by successive calculations of temperature and crystallinity throughout the whole process. In addition, a graphic method is presented to predict crystallization temperature. By using the plateau temperature observed in melt-spinning experiments, the crystallization rate under molecular orientation is evaluated. Furthermore, a method applicable to estimating the ultimate crystallinity is proposed. A rough estimation of the increase in the rate of crystallization under molecular orientation was carried out for very high-speed spinning of poly(ethy1ene terephthalate ).

SynopsisCrystallization during melt spinning is studied as an example of the nonisothermalThe following equation is derived, taking the temperature crystallization of polymers. distribution within a filament into consideration :heat of crystallization, and C, = specific heat at constant pressure. The assumptions and the procedure for a numerical calculation of crystallinity and temperature within a running filament are described, and some results of calculation are illustrated. The results are compared with those obtained by a simpler calculation in which the radial temperature distribution is neglected. The simpler method proved useful in connection with x-ray measurements.

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The piezoelectricity of cyanoethylated hydroxyethylcellulose was investigated. Elastic, piezoelectric, and dielectric relaxations were observed at -80 ° to -60°C and 0 ° to 20°C at a frequency of 10Hz. The activation energy is about 9-15kcal/mol in the low temperature region and about 30-45kcal/mol at room temperature. These relaxations in the low temperature region may be caused by the motion of the cyanoethyl group and those at room temperature mostly by the motions of the main chain. Cyanoethylated hydroxyethylcellulose has a high piezoelectric strain constant (d25), which is the largest value among the cellulose derivatives and is almost the same as the value for polyvinylidene fluoride. The electromechanical coupling factor for cyanoethylated hydroxyethylcellulose was small.

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