Polymethylmethacrylate pyrolysis

A special case in terms of application of rotary kiln technology is the pyrolysis of mono fractions such as styrene, PMMA, polycarbonate, or polyethylene terephthalate. Polymethylmethacrylate is an example illustrate the advantages in using fluidized beds or rotary kilns. The feed material does not have a heteroatom problem and the pyrolysis product can easily be handled as a monomer source instead of feedstock. Therefore the... 

The critical values of the mass pyrolysis rate, heat release rates, and water application rates for flame extinction for polymers, are listed in Table 53.14. For the polymers listed in the table, the critical values of the heat release rates do not depend on the generic namres of the polymers. The average critical values of the chemical, convective, and radiative heat release rates are 100 + 7, 53+9, and 47 +10 kW/m, respectively. The critical water application rate required for flame extinction is polyoxymethylene, polymethylmethacrylate and polyethylene with 25% chlorine (2.1-2.5g/m -s)[Pg.913]

Shimizu and coworkers (Hieda et al. 2(X)8 Hayashi et al. 2009 Morio et al. 2009 Hyodo et al. 2010) have shown that, by using a modified sol-gel technique, pyrolysis or a physical vapor deposition process employing a polymethylmethacrylate (PMMA) microsphere film as a macropore template, macroporous (mp-) films of various materials promising for gas sensor application can be fabricated. They established that different kinds of gas sensors fabricated with the mp-semiconductor films (SnOj and In Oj to detect H, NO, and H S), photoluminescence-type (SnO mixed with Eu Oj to detect and NO ), and quartz crystal microbalance type (BaCOj to detect NO ) showed stronger gas responses as well as fast response and recovery speeds in comparison with those fabricated with a conventional film and powders without macropores (Hayashi et al. 2(X)9 Yuan et al. 2011 Hyodo and Shimizu 2011). 

Hyodo T, Inoue H, Motomura H, Matsuo K, Hashishin T, Tamaki J, Shimizu Y, Egashira M (2010) NO sensing properties of macroporous InjO -based powders fabricated by utilizing ultrasonic spray pyrolysis employing polymethylmethacrylate microspheres as a template. Sens Actuators B Chem 151 265-273... 

Some polymers, (e.g. polymethylmethacrylate, polystyrene) lead to good yields of monomer on pyrolysis. Similarly, poly(ethylene terephthalate), PET results in good recovery of monomers on hydrolysis. There is also a case for pyrolysing contaminated mixed plastics packaging to obtain a mixture of hydrocarbons. It can be seen from Table that at moderate temperatures in a fluidised bed pyrolysis unit, ethene and propene are major products with methane and ethane in almost equal amounts. The latter and the scores of other compounds that have been detected in small amount have fuel value. 

Figure 6.3 Pyrolysis-FTIR spectra of (a) polystyrene, (b) Nylons, (c) PVC and (d) polymethylmethacrylate - continued overleaf.

Figure 6.9 Pyrolysis-gas chromatography pyrogram of polymethylmethacrylate. Reproduced with permission from T.M. Wu, T.F. Yin and S.F. Hsu, Macromolecular Science B, 2004, B43, 329. 2004, Taylor Francis...

Davidson [15] applied programmed pyrolysis - evolved gas IR spectroscopic techniques to determine whether for polymethylmethacrylate (PMMA) the evolution profiles of various pyrolysis gases against temperature were sufficiently distinctive to allow reliable identification of different types and to distinguish between different batches of the same type. The results showed that the different types and batches could be reliably identified. Reactions accounting for some of the compounds evolved... 

Lehmann and Brauer [22] and Brauer [23] investigated the Py-GC of polymethylmethacrylate at temperatures between 400 °C and 1100 °C using a silica boat surrounded by a platinum heating cell for the pyrolysis. 

Mukundan and Kishore [25] showed that low temperature pyrolysis of polymethylmethacrylate peroxide gave methylpyruvate and formaldehyde as primary pyrolysis products. Above 350 °C secondary pyrolysis products appear. 

Figure 3.20 shows a pyrogram of polymethylmethacrylate copolymerised to contain 1 and 10% of acrylic or methacrylic acid. By this procedure, copolymerised acrylic or methacrylic acid has been identified in terpolymers with (a) butyl acrylate and styrene, (b) methylmethacrylate and ethyl acrylate and, (c) ethylene and propylene. A methyl methacrylate - methylstyrene - maleic acid terpolymer, when examined by this propylation - pyrolysis procedure, yielded dipropyl fumerate and a smaller amount of dipropyl maleate. 

Pyrolysis coupled with simultaneous multidetector gas chromatography has been applied to studies of Ae structure of end-groups in polymethylmethacrylate. ... 

Figure 1.7 Chromatograms of pyrolysis products of polymethylmethacrylate column, dinoyl phthalate (a) top pyrolysis temperature 425 °Q column temperature ...

Figure 2.1(d) shows the spectrum of pyrolysed polymethylmethacrylate (PMMA). A carbonyl stretching bands is clearly present at 1745 cm. Also evident is an ester CH3-O stretch at 1018 cm. The spectrum obtained in the pyrolysis experiment can be directly compared to a reference spectrum of methyl methacrylate (MMA). 

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