New concepts on optimising initiator efficiency and making square heat profiles in poly(vinyl chloride)

Initiator performance is determined by halflife temperature and peroxide efficiency. This peroxide efficiency is temperature dependent. Efficient use of an initiator is realised if, after a polymerisation cycle, all the initiator is consumed and transferred into polymer. To realise efficient use of inilialors, the use of fast initiators is recommended. Some fast initiators lose too much efficiency at high temperatures, but 1,1,3,3-tetramethylbutyl peroxyneodecanoate is a fast peroxide that does not lose much of its efficiency at high temperature and can help to increase poly(vinyl chloride) (PVC) output. The use of very fast peroxides can also help lo increase PVC output. An example of a polymerisation reaction is described using diisobutyryl peroxide as the initiator, to make flexible PVC. In this process an almost square heat profile is realised.