Method of plasma initiated polymerization
AssigneeThe Regents of the University of California
InventorsYoshihito Osada, Alexis T. Bell, Mitchel M. Shen
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Abstract
An ionized gas plasma is established in an electrical field in contact with a non-vapor volume of monomer (liquid and/or solid). The plasma creates active polymerization sites in the monomer volume to initiate propagation of polymerization therein. After initiation, the partially-polymerized monomer volume is postpolymerized in the absence of the ionized gas plasma to yield a very high molecular weight polymer which may be essentially free of cross-linking in desirable forms including commercial quantities of bulk self-supporting polymer or a coating. Suitable monomers include liquid vinyl monomers (e.g., methyl, methacrylate) and solid crystalline monomers (e.g., 1,3,5-trioxane).
Claims32
A method of plasma initiated polymerization, comprising the steps of:
- (a) establishing and maintaining a contained zone of ionized gas plasma in contact with a surface of continuous solid or liquid volume of substantially unpolymerized monomer, said ionized gas phase being established and maintained by an electric field which creates a path of electrical conduction totally within said contained zone,
- (b) commencing propagation polymerization of said monomer volume by the creation of active polymerization sites at the interface between said gas plasma and monomer volume caused by activation derived from said ionized gas plasma to partially polymerize said monomer,
- (c) terminating contact between said partially polymerized monomer volume and ionized gas plasma substantially prior to the desired conversion of monomer to polymer and the desired final molecular weight of polymer, and
- (d) postpolymerizing said partially-polymerized monomer volume in the absence of ionized gas plasma to convert monomer to polymer in a proportion of at least two times that converted prior to termination of plasma contact and to yield the desired high molecular weight.
Dependencies are inferred from the claim text.