Polymethyl methacrylate processing data

The current interest is the examination of the consequences of fiee-volume theory on the effect of the solvent size on diffusional behavior, and the behavior of the diffusion process near the glass transition. Clearly, these two problems are interrelated. The experimental data needed to investigate both are accurate diffu-sivity-temperature data for a series of solvents that covers a wide range of molecular sizes. The series of solvents used should include solvents of large molecular size, incapable of segmental motion. Some recent work is reported hoe using polymethyl methacrylate, an amorphous polymer that can be studied over a wide temperature range. 

In addition to the data just presented, the normalized correlation function has been determined in [22] for particles of suspended polymethyl methacrylate and loess deposits, with particle diameters from 15 to 45 pm. Calculations with a BESM-2M computer, using an algorithm developed for this purpose, show that the normalized correlation function under these conditions varies around a value close to unity, which indicates the stability of the process. 

All the data shown in Fig. 11-31 fall on a definite curve regardless of extrusion rate. Again, the curve shapes match polymethyl methacrylate polymerization curves. And, again, this would seem to indicate that chemical reaction was the prevailing rate process. 

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