Copolymers and terpolymers based on chlorotrifluoroethylene and vinyl chloride and uses thereof
Disclosed are copolymers and terpolymers chlorotrifluoroethylene and vinyl chloride having improved properties, and particularly a high glass transition temperature, for use in membranes, coatings, barrier films, and other applications and process for forming such copolymers and terpolymers, which are useful in reverse osmosis desalination, nanofiltration, ultrafiltration, microfiltration, membrane distillation, pervaporation, selective gas separation, batteries and fuel cells.
1. A process of making copolymers or terpolymers comprising chlorotrifluoroethylene (CTFE) monomeric units and vinyl chloride (VC) monomeric units and optionally one or more third monomeric units, said process comprising:
(a) providing an initial reaction medium containing CTFE monomers and VC monomers in a CTFE:VC weight ratio of from about 50:50 to about 5:95; and
(b) reacting said CTFE monomers and said VC monomers by introducing to the reaction medium said CTFE monomers and said VC monomers under conditions to produce a copolyomer or terpolymer comprising VC monomeric units in a weight percentage (based on the total weight of the copolymer or terpolymer produced) that is within 2 percent of the weight of said VC monomers introduced to the reaction medium (based on the total of monomers introduced to the reaction medium), wherein said conditions include conducting said reaction at temperatures in the range of from about 20° C. to about 50° C. for a period of at least about 15 hours to produce a copolymer having a glass transition temperature of from about 70° C. to about 87° C.
2. The process of claim 1 wherein the copolymer or the terpolymer has a Tg of from about 75° C. to about 87° C., a weight average molecular weight from about 100,000 to about 300,000 Daltons, and a surface energy from about 32 to about 38 mJ/m 2 .