Controlled polymerization

A control agent and polymer technology, applied in the field of controlled polymerization, can solve the problems of slow initiation speed, undesirable, long reaction time, etc.

Inactive Publication Date: 2006-04-05
THE GOODYEAR TIRE & RUBBER CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The two main disadvantages of the miniemulsion technique are (1) the need for specialized, expensive equipment, and (2) the use of hydrophobes (such as hexadecane), which is undesirable in many possible applications
Although this technique has certain advantages over miniemulsion techniques because it does not require hydrophobes or specialized equipment, it does not address the fundamental problems of using controlled polymerization techniques in emulsions, such as the initiation of slow or long response time

Method used

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  • Controlled polymerization
  • Controlled polymerization
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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0184] Surfactant systems for in situ emulsification in styrene

[0185] A series of reactions were performed to identify potential surfactant / surfactant activator combinations for in situ emulsification. In a typical reaction, a solution of latent surfactant (~0.2 g) in styrene (5 mL) and a solution of surfactant activator in water (5 mL) were prepared and the aqueous solution was added to In styrene solution, an emulsion is produced. Selected latent surfactant / surfactant activator combinations to produce emulsions are summarized in the table below:

[0186] serial number

Embodiment 2

[0188] Control by RAFT methodM n Polymerization of polystyrene with PDI

[0189] A 2 gallon reaction vessel was first charged with 1,000 grams of styrene, 60.0 grams of oleic acid, and 7.2 grams of dibenzyl trithiocarbonate. The reactor was then purged with nitrogen, evacuated briefly, and charged with an aqueous solution containing 4,000 grams of RO water, 40.0 grams of potassium persulfate, 40.0 grams of tripotassium phosphate, and 16.4 grams of potassium hydroxide. As soon as the aqueous solution is mixed with the preceding organic material, a fine microemulsion is formed. The resulting mixture was then rapidly heated to 65°C. Complete conversion to a stable slightly yellow polystyrene latex occurred in less than 1.5 hours. The solids obtained after stripping were 20.6%. GPC analysis of the final polymer revealed that its M n at 54,000 with a PDI of 1.17.

Embodiment 3

[0191] Via the RAFT method using in situ generated polymerizable surfactants

[0192] Take Control M n Polymerization of polystyrene with PDI

[0193] A 2 gallon reaction vessel was initially charged with 1,000 grams of styrene, 60.0 grams of cetyl half ester of maleic acid and 7.2 grams of dibenzyl trithiocarbonate. The reactor was then purged with nitrogen, evacuated briefly, and charged with an aqueous solution containing 4,000 grams of reverse osmosis (RO) water, 40.0 grams of potassium persulfate, 40.0 grams of tripotassium phosphate, and 16.4 grams of potassium hydroxide. It should be noted that upon mixing the aqueous solution with the preceding organic material, a fine microemulsion is formed. The resulting mixture was then rapidly heated to 65°C. Complete conversion to a stable slightly yellow polystyrene latex occurred in less than 3 hours. The solids obtained after stripping were 23.7%. GPC analysis of the final polymer revealed that its M n ...

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Abstract

The present invention discloses an emulsion polymerization process that comprises: (1) preparing an aqueous polymerization medium which is comprised of (a) at least one monomer, (b) a polymerization control agent, and an emulsifier, wherein the emulsifier is prepared in-situ within the aqueous polymerization medium; and (2) initiating polymerization of said monomer within the aqueous polymerization medium. The subject invention more specifically reveals an emulsion polymerization process that comprises: (1) preparing a monomer solution which is comprised of (a) at least one monomer, (b) a conjugate acid of a surfactant with a pKa of less than 14, and (c) a controlled free radical polymerization agent; (2) preparing an aqueous medium which is comprised of (a) water, and (b) a conjugate base of a weak acid wherein the pKb of the base is less than 14; and (3) mixing the monomer solution with the aqueous medium under conditions that result in the in-situ formation of an emulsifier, and (4) initiating free radical polymerization.

Description

[0001] This application claims priority to US Provisional Application Serial No. 60 / 437,542, filed December 31,2002. field of invention [0002] The present invention relates to methods and compositions for controlling polymerization in emulsion systems using a variety of monomers under a variety of conditions. The invention also relates to a process for preparing said emulsion system. Furthermore, the invention relates to polymers and copolymers which can be prepared with said emulsion systems. Background of the invention [0003] Synthetic polymers are a large family of materials with a relatively wide range of applications. The basic building blocks of polymers are called monomers, and various methods have been invented to prepare polymers from monomers. The earliest efforts to make polymers focused on controlling the molecular formula of polymers and making useful materials from readily available chemical starting materials....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F2/24C08F2/38
Inventor D·K·帕克F·J·菲赫V·马哈德文
Owner THE GOODYEAR TIRE & RUBBER CO
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