Methods of sulfonating a polymer are provided. One method of sulfonating a polymer includes exposing sulfur dioxide and oxygen to free radical producing energy and contacting the polymer with the product of preceding step. Desirably, the steps of exposing sulfur dioxide and oxygen to free radical producing energy and contacting the polymer with this product are performed in a reduced pressure environment. Another method of sulfonating a polymer includes contacting the polymer with sulfur dioxide and oxygen and exposing the contacted polymer to free radical producing energy. The polymer may be contacted with a mixture of sulfur dioxide and oxygen or the polymer may be separately contacted with sulfur dioxide and oxygen. When the polymer is separately contacted with sulfur dioxide and oxygen, the polymer may first be contacted with sulfur dioxide and then contacted with oxygen. The source of the free radical producing energy may be ultra-violet light, electron beam, noble gas radio frequency (rf) plasma, corona discharge, or gamma radiation.
展开▼
