Initiators storage, transport, packaging

On the other hand, the stabilization of monomers for storage in the factory or during road, rail or sea transportation, is a great problem in terms of monomer quality, and especially in terms of safety. Indeed, for all vinyl monomers, the polymerization reaction is exothermic and autocatalytic once initiated. It is therefore very difficult to have storage equipment that can withstand such pressures (ref. 23). The main selection criteria for such package-inhibitors are their effectiveness at ambient temperature, their colourlessness and their ability to be removed before polymerization or to be overcome by the use of moderate amounts of initiator under the customer s polymerization conditions. 

A similar situation does not presently exist for multilayer retortable food packages. In our initial study of LEP and PEP food packages we found that there are very few experimental studies on water permeation in polymers. The studies which we did find were usually limited to low temperature, far removed from retort conditions. The effect of water activity on transport and sorption behavior has not received much attention especially for water-sensitive polymers such as EvOH. In EvOH-type systems the problem is especially acute because EvOH exhibits case II sorption at moderate humidities and its effective glass transition is depressed below storage temperatures at high humidities. Thus, modelling the transport in this type of material is very complex and does not lend itself to analysis with existing models. 

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