PMMA, additives Stabilisers

Neville and Hunter [6] studied the flocculation of poly(methylmethacrylate) (PMMA) latex stabilised with poly(ethylene oxide) (PEO). Flocculation was induced by the addition of electrolyte and/or an increase in temperature. Figure 21.12 shows the variation of with increase of temperature at constant electrolyte concentration. In the figure, it can be seen that increased with increases of temperature, reaching a maximum at the critical flocculation temperature (CFT), and then decreased with further increase in temperature. The initial increase was due to the flocculation of the latex with increase of temperature, as the result of a reduction in solvency of the PEO chains with the increase in temperature. The... 

It is necessary to be able to identify and quantify the additives in polymers and vibrational spectroscopy is a particularly useful approach to this problem. Compared with traditional chemical analyses, vibrational methods are nondestructive and are time-and cost-effective as well as more precise. A large number of examples exist in the literature. For example, antistatic agents (polyethylene glycol (PEG) in polyethylene (PE)) can be detected directly using FTIR sampling (367). An IR spectroscopic technique for the analysis of stabilisers (2, 6-di-tert-butyM-methylphenol) in PE and ethylene-vinyl acetate (EVA) copolymer has been described (368). It is possible to quantify the amount of external and internal lubricants (stearic acid in polystyrene (PS)) (371). Fillers in polymers can also be analysed (white rice husk ash (predominantly silica in polypropylene (PP)) (268). Raman spectroscopy has been used to detect residual monomer in solid polymethyl methacrylate (PMMA) samples (326). 

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