Divinyl benzene degradation

Sinister, C., F. Caron, and R. Gedye. 2004. Determination of the thermal degradation rate of polystyrene-divinyl benzene ion exchange resins in ultra-pure water at ambient and service temperature. J. Radioanal. Nucl. Chem. 261 523-531. 

Nakagawa and co-workers [18] used techniques based on high resolution Py-GC and Py-GC and TGA to measure thermal degradation of chloromethyl substituted polystyrene. A typical TGA weight loss curve is shown in Figure 4.1. Degradation starts at 200 "C and peaks at 400 °C. Typical pyrolysis products of chloromethylated styrene-divinyl benzene (St-DVB) copolymers are the monomers, dimers and trimers of styrene, p-methyl styrene, and divinyl and ethyl styrene. For styrene chloromethyl St-DVB copolymers, in addition to the above, /-methyl styrene monomer and m- and p-chloromethyl styrene monomers are also present in pyrolysates. 

Isobutylene-lsoprene-Divinylbenzene Terpolymers. A partially cross-linked terpolymer of isobutylene, isoprene, and partially reacted divinyl benzene is commercially available from Rubber Division, Bayer Inc., Canada. The residual vinyl functionality may be cross-linked with peroxides, a treatment that would normally degrade conventional butyl rubbers. This material is used primarily in the manufacture of sealant tapes and caulking compounds (45). 

Figures 9.8(a) and (b) show mass spectra as a fimction of temperature for the thermal degradations of uncrosslinked PS (M = 1,000,000) and 12% divinyl benzene crosslinked PS. The difference between the samples is clearly shown, as the heavily crosslinked PS starts to degrade at a lower temperature and the degradation occurs over a wider temperature range. These differences appear even more dramatic in Figures 9.8(c) and (d) which show the profiles for specific ions (105, 117, 209, and 221 miz) as a function...

Figure 9.8 (a) Three-dimensional plot for thermal degradation at 16 °C/s of uncrosslinked polystyrene (M, 100,000) shown as m/z versus intensity versus scan number (10 = 73 °C, 30 = 563 °C). (b) Three-dimensional plot for thermal degradation at 15.5 °C/s of polystyrene - 12% divinylbenzene, shown as m/z versus intensity versus scan number (10 = 97 °C, 30 = 564 °C). (c) Specific non profiles for thermal degradation at 16.0 °C/s of uncrosslinked polystyrene (M, 100,000) shown as intensity versus scan number (A) Mass 105 m/z temperature of evolution maximum 423 °C (B) Mass 117 m/z temperature of evolution maximum 423 °C (C) Mass 209 m/z temperature of evolution maximum 423 °C (D) Mass 221 m/z, temperature of evolution maximum 423 °C. (d) Specific ion particles for thermal degradation at 15.5 °C/s of polystyrene - 12% divinyl benzene shown as versus scan number (A) Mass 105 m/z, temperature of evolution maximum 423 °C (B) Mass 117 m/z, temperature of evolution maximum 423 °C (C) Mass 209 m/z, temperature of evolution maximum 423 °C (D) Mass 221 m/z, temperature of evolution maximum 423 °C Reprinted from T.H. Risby, J,A. Yergey and /./. Scocca, Analytical Chemistry, 1982, 54, 2228, with permission from the American Chemical Society [154])... 

The polymer support used in these reactions should have a reasonably high degree of substitution of reactive sites. In addition, it should be easy to handle and must not undergo mechanical degradation. There are several polymers in use, but the most common one is the styrene-divinyl benzene copolymer. 

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