Sentence:  ( 2 ) In the <WSD>critical</WSD> micelle region , there is a rapid agglomeration or polymerization to give the micelles , which have a degree of polymerization averaging around 60 - 80 . 
Meaning of the word marked with <WSD> tags:  at or of a point at which a property or phenomenon suffers an abrupt change especially having enough mass to sustain a chain reaction