| Summary: | 碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 96 === Isotactic Poly(4-methyl-1-pentene)(P4MP) can be affected by the interaction of solvent molecule in solution. The appropriate chain conformation of P4MP will be varieties at different temperature and solvent, and the different chain conformations will make P4MP molecules have variety of aggregation behavior in solution, including gelation network composition and crystal growth.
The dissertation discovers P4MP molecules can form gelation network in dilute solution by using isothermal crystallization. Gelation network can be discovered in dilute solution briskly, as the solution quenches from dissolution temperature to isothermal crystallization temperature. When we consider the solution concentration and the rate of becoming gelation network, the mechanism of gelation networks are different from liquid-liquid phase separation, which require super-cooling and stirring.
The gelation network in dilute solution by isothermal crystallization will transform to crystal phase with time. In experiment, the crystal growth of gelation network by low temperature xylene solution can form lamellar structure perpendicular to gelation network direction. The lamellar crystal can be welding with isothermal time increase. The gelation network of isothermal crystallization by p-xylene in low temperature, because p-xylene can increase P4MP molecules crystallization rate, which make welding phenomenon difficult to observe in low temperature p-xylene solution.
The gelation network of P4MP molecules in p-xylene solution, because different isothermal temperature, the growth mechanism of lamellar crystal can also be different. The lamellar crystal growth of gelation network in high temperature p-xylene solution will be parallel to gelation network direction, which is different from lamellar crystal in low temperature solution. This shows that the growth mechanism of P4MP molecules gelation network in solution is different because difference of isothermal temperature. We can further verify that in solution, the interaction between polymer and solvent are affected by isothermal temperature and result in the difference of crystallization behavior in gel because the growth and pile of lamellar crystal in gel.
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