[Ti3sto]

I'd like to know what type(s) of polymerization are involved in polycarbonate.

[xiankai]

im assuming its an addition polymer, since the only polymerisations i know are addition and condensation.

since it doesnt form water as one of the products ( the carbonate is connected to carbon atoms on the repeating structure, not hydrogen), it cant be a condensation polymer

[Ti3sto]

Thank you so much  

[DrCMS]

Addition polymerisation involves double bonds reacting to give chain growth, usually initiated by free radicals.  Polycarbonate synthesis is NOT addition polymerisation.

The synthesis of polycarbonate is a step-growth polymerisation, from most often bisphenol A and phosgene to make LEXAN™.

The first step in the synthesis of polycarbonate from bisphenol A is treatment of bisphenol A with sodium hydroxide.  This deprotonates the hydroxyl groups of the bisphenol A molecule, this deprotonated oxygen reacts with phosgene to form a chloroformate.   The chloroformate is then attacked by another deprotonated bisphenol A, eliminating the remaining chloride ion and forming a dimer of bisphenol A with carbonate linkage and two molecules of sodium chloride.

Repetition of this process yields polycarbonates, hence step growth polymerisation.


Addition or chain growth polymerisation needs a monomer and initiator and gives a ploymer chain.

Condensation or step growth polymerisation need two different types of chemical to reacts to give a polymer chain plus small molecules such as, but not always, water.