Monomer migration

Baner, A. L. (2000). Case study Styrene monomer migration into dairy products in single serve portion packs. In "Plastic Packaging Materials for Food Barrier Function, Mass Transport, Quality Assurance, and Legislation" (O.-G. Piringer, and A. L. Baner, eds.), pp. 427-443. Weinheim (Feberal Republic of Germany), Wiley-VCH. 

The hydrolysis of ECH is so rapid at 40 °C, even in neutral aqueous media (water, 10% ethanol) as well as acidic (3% acetic acid, 0.01 N HC1) and alkaline (0.01 N NaOH) media, that specific determination of this residual monomer migration from epoxy lacquers into these media causes inconsistent and erroneous results. Due the fact that the overall rate of hydrolysis contains the sum of all contributions from nucleophiles present in aqueous systems, one can find a rapid decomposition of ECH even in foods with neutral pH, due to their complex composition. 

Case study styrene monomer migration into dairy products in single serve portion packs... 

Durst, G., Laperle, E. 1990. Styrene monomer migration as monitored by purge and trap gas chromatography and sensory analysis for polystyrene containers. J. Fd. Science. 55 522-524. 

Lickly, T. D., Rainey M. L. Burgert L. C., Breder C. V., Borodinsky L. 1997, Using a simple diffusion model to predict residual monomer migration - considerations and limitations. Food Additives and Cntaminants, 14. 65-74. 

Miltz, J., Elisha, C Mannheim, C. 1980. Sensory threshold of styrene and monomer migration from polystyrene food packages. J. Food Processing and Preservation. 4 281-289. 

Cases III and IV are of direct interest to the packaging industry. Case IV, in fact, relates directly to monomer migration in blow-molded bottles. Daniels and Procter have treated simultaneous diffusion of VCM into the environment and into the package contents over a time scale sufficient to invalidate the assumption of independent diffusional processes at each of the bottle wall boimdaries. Over relatively short time periods, approximately half of the VCM originally sorbed in the bottle wall tends to diffuse into the environment and be swept away while the crther half (in the inside half of the wall) tends to diffuse into the package contents and increase its VCM content. Such a simultaneous process increases the VCM concentration at the... 

Figure 2. Particle size distribution when only monomer migration is possible. Equation 26 with p

The producing of the polymeric nanocomposite in situ is the intercalation of the monomer into the clay layers. The monomer migrates through the organoclay galleries and the polymerization happens inside the layers [19,51] (Figure 13). 

The chain polymers that are treated in this text are lignin, polyethylene, polystyrene, and polyvinyl chloride. The reactions which form these polymers are summarized in TaHe 3. Again, for the four synthetic polymers of Table 3, there are often several reactions which produce the polymer and only one representative reaction is shown. Note that all of these reactions involve a monomer migrating to an active site to form another link and ultimately thereby form a polymer. 

Giacin, J. R. Additive and Monomer Migration/Diffiision in Plastics. Medical Device and Diagnostic Industry, pp. 35-38, Feb. 1983. 

Apparent reactivity ratios obtained directly from suspension polymerization experiments may not be identical to those expected from the equivalent bulk processes if some monomer migrates to the continuous phase. Ashady et al. [10] found values for reactivity ratios that were not expected from results observed in bulk or solution copolymerization. Izumi and Kitagawa [11] showed that reactivity ratios for suspension copolymerization, of acrylonitrile and methyl acrylate, were different from those obtained from either solution or emulsion polymerization. Table 5.1 compares reactivity ratios obtained from solution copolymerization with those observed in suspension copolymerization. 

In situ polymerization was the first method used to synthesize polymer-clay nanocomposites based on polyamide (PA) 6. In this technique, the modified layered silicate is swollen by a liquid monomer or a monomer solution. The monomer migrates into the galleries of the layered silicate, so that the polymerization reaction can occur between the intercalated sheets. The reaction can be initiated either by heat or radiation, by the diffusion of a suitable initiator or by an organic initiator or catalyst fixed through cationic exchange inside the interlayer before the swelling step by... 

Another topic that merits discussion is the consideration of residual monomer in polymer formulations. Whole polymer samples, rather than food simulating solvent extracts of the polymeric material are sometimes assayed for residual monomer. The thought here is that if the amount of residual monomer in a formulation is low enough, and if one assumes that all of the residual monomer migrates into food, the human health impact... 

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