Expandable polystyrene is use extensively for protecting storing and serving many different food product (ps1)
Incorporation of the blowing agent in expandable PS
beads can be achieved by the addition of the blowing
agent during the suspension polymerisation process. In
this process, the monomer is suspended as droplets in
water, stabilised by a suspending agent and subsequently
polymerised. The blowing agent (usually a mixture of pentane isomers) is introduced into the closed suspension
reaction vessel during the final stage of polymerisation [5] at
a temperature well above the glass transition temperature,
Tg, of PS, resulting in dissolution of pentane in the PS beads.
After cooling, the blowing agent is entrapped in the PS
beads