| Summary: | 碩士 === 國立臺灣科技大學 === 高分子工程系 === 91 === ABSTRACT
In this work, the effects of mixed solvent (H2O/DMSO) on gelation behaviors in agarose/water/DMSO mixtures were studied through intrinsic viscosity, gelation kinetic analyses, dynamic mechanical analyzer(DMA,7e) and time-resolved small angle light scattering (TR-SALS) measurements. The purpose of this quotation is to show gelation mechanism and percolation behavior of physical gelation and biostructural polysaccharide. In a series of analyzed discussions, we have studied mechanism and formation of agarose gels in mixed solvents of H2O and DMSO. In agarose/water/DMSO ternary system, the solution be can formed DMSO(H2O)2 complexes with hydrogen bond, in molecular ratio of 1 (DMSO) : 2 (H2O). It is meaning that DMSO molecules interact strongly with H2O molecules and the results appear a critical value. Hence, the agarose/water/DMSO system with various volume ratio lead to varied gelation mechanism. In other words, phenomenon of the gelation kinetic aspects with cosolvent effect is perplexity. We have attempted to examine the gelation characteristic exponent physical meanings. When 9/1, 8/2, 7/3, 5/5 and 4/6 of the solvent composition belong to phase separation control contribution. On the contrary, three-dimensional percolation behaviors occur in the solvent ratio (6/4). Even so, experimental results concerning the phase separation of agarose solution are attributed to the spinodal decomposition and described with Cahn’s linear theory in detail. In order to examine the universality of percolation theory for the description of critical behavior of the correlated percolation, it seems of importance to compare critical exponent experiments. On experimental result is presented that three-dimensional percolation model with DMA, resulting in the elasticity exponent appropriate for the conductivity exponent of the percolating resistor network. In summary, we focus on the gelation mechanism and percolation behavior of polymer gelation which tries to describe physical meanings.
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