PMMA/sulfolane

Simulation results in binary amorphous polymer/solvent systems have been obtained for a poly(methyl methacrylate) (PMMA)/sulfolane system (Caneba and Soong, 1985b), which has a UCST of 51°C. For a polystyrene (PS)/cyclohexanol system with a UCST of 82°C, simulation results are presented by Caneba and Saxena (1996). Table 1.4.1 shows parameter values used in these systems. 

Parameter PMMA/sulfolane system PS/cyclohexanol system... 

Two-dimensional (Chen et al 1993) and three-dimensional simulations have also been done for the binary PMMA/sulfolane system at 30" C and overall polymer weight fraction, Co=0.10. For this system, the one-dimensional simulation... 

Based on the results from these simulations from one dimensional to three dimensional, we note that the eariy-stage behavior involves the smallest possible structure that can be obtained in the system. Superimposition of a numerical structure from the three-dimensional calculation (Fig. 1.4.8) for the PMMA/sulfolane system... 

Fig. 1.4.7 Polymer composition profile (a) contour view with 1 wt% polymer composition difference between adjacent curves and (b) isometric view of wt% polymer relative to overall wt% polymer of the early-stage spinodal decomposition of the PMMA/sulfolane system at 30°C, Co = 0.10, time = 2x10 s, and percent completion = 21.6%. Distances are in micrometers...

Fig. 1.4.8 Results of three-dimensional simulation of the PMMA/sulfolane system at 30°C, as a stack in inclined view of two-dimensional contour plots. Two-dimensional domains are from —0.96 to -tO.96 ttm, while the vertical domain (top profile) starts at -0.86 p.m and ends at the bottom profile at -tO.86 p.m...

Fig. 1.4.9 Superimposition of numerical results of three-dimensional simulation of PMMA/sulfolane system at 30°C (shown in Fig. 1.4.8) with experimental data of a membrane portion showing early-stage pore stmcture (Caneba and Soong, 1985b)...

A liner containing glass wool was installed in the injection port of the GC to trap polymer residues. A solution containing a known amount of the carbamate in THF along with sulfolane as an internal standard was used to establish the concentration of carbamates in the PMMA and PPMA matrix. Quantum yields were then determined. Product ratios were calculated from UV difference spectra (taken on a Beckman DK-2A spectrometer) of films before and after photolysis. 

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