Thermal-History Dependence of Dynamics of Polymerization-Induced Phase Separation and Its Mechanisms

1998 Fiscal Year Final Research Report Summary

• Project/Area Number: 09650988
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 高分子構造・物性(含繊維)
• Research Institution: TOKYO INSTITUTE OF TECHNOLOGY
• Principal Investigator: OKADA Mamoru Tokyo Institute of Technology Faculty of Engineering Associate Professor, 工学部, 助教授 (50185451)
• Project Period (FY): 1997 – 1998
• Keywords: Phase separation / Thermal history / Domain structure / Pattern formation / Polymer blend / Thermosetting resin / Polymerization / Light scattering

Research Abstract

Thermal-history dependence of polymerization-induced phase separation of a monomer/polymer mixture was studied by making a stepwise temperature change to a higher temperature T_2 in the course of phase separation. Morphological structure of domains after the temperature change strongly depended on the duration t_1 at the initial phase-separation temperature : Morphological change from droplets to continuous domains occurred when the duration was longer than a certain value. Thermal-history dependence was found in the time evolution of scattered light intensity as well : After the second jump, the peak intensity I_m approached the curve of I_m vs. time t for the single-step jump to T_2 in the case of short t_1, while in the case of long t_1 increased rapidly beyond the curve for the single step to T_2. The shortest duration time t_1 required for occurrence of morphological change after the temperature change was strongly dependent on the initial phase-separation temperature T_1 but independent of the second temperature T_2. These results were explained as follows : Polymerization reaction was faster than phase separation at a lower temperature where mobility of the system was low, while phase separation was faster than reaction at a higher temperature where the mobility was high. In other words, the morphological change at T_2 was caused by the polymerization product accumulated in the sea phase at T_1.
Polymerization-induced phase separation was found to have a large thermal-history dependence, and examination of thermal-history dependence gave valuable information about polymerization-induced phase separation and was proved to be a very useful method for elucidating the mechanisms of this phenomenon.