Ultrasonic polymerization process
OwnerJames O. Stoffer, Oliver C. Sittoninventors
Life of this patent
Estimating the term…
Abstract
Polymerization of ethylenically unsaturated monomers such as methyl methacrylate can be initiated in solutions containing monomer and a special non-polymeric initiator with intense ultrasound. The number average molecular weight of the poly(methyl methacrylate) that forms is about 300,000 gmol.sup.-1 as compared with polystyrene standards. The conversion of the polymerization is about 50% for poly(methyl methacrylate). Variations of the polymerization rate with time and the amount of the initiator are explained by a simple reaction mechanism.
Claims25
A process for polymerizing at least one ethylenically unsaturated monomer comprising providing a mixture of the monomer and a non-polymeric initiator which responds to ultrasonic energy to form free radicals, and subjecting the mixture of monomer and initiator to sufficient ultrasonic energy to cause the initiator to form free radicals, the process being carried out at a bulk temperature below 40.degree. C. to produce at least 20% conversion of monomer to polymer.
In the method of polymerizing at least one ethylenically unsaturated monomer by free radical initiation, the improvement comprising a step of adding a non-polymeric initiator which is broken down by ultrasonic energy to produce free radicals without added heat, a step of subjecting said initiator to ultrasonic energy sufficient to break the initiator down to produce free radicals without raising the bulk temperature of the monomers above about 40.degree. C., and a step of continuing polymerization until at least 20% of the monomer has been polymerized.
A process for polymerizing at least one ethylenically unsaturated monomer at a bulk temperature below about 40.degree. C. comprising providing a mixture of the monomer and a non-polymeric initiator which responds to ultrasonic energy to form free radicals, subjecting the mixture of monomer and initiator to sufficient ultrasonic energy to cause the initiator to form free radicals, and incrementally adding further of the initiator as polymerization proceeds.
In a process for polymerizing at least one ethylenically unsaturated monomer by applying ultrasonic energy to the monomer, the improvement comprising adding to the unsaturated monomer a non-polymeric initiator which responds to ultrasonic energy by forming free radicals and causing polymerization of at least 20% of the monomer in no more than 30 minutes at a bulk temperature of less than about 40.degree. C.
Dependencies are inferred from the claim text.