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Preparation of Highly Syndiotactic Polymethylmethacrylate

IP.com Disclosure Number: IPCOM000082354D
Original Publication Date: 1974-Nov-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Johnson, DE: AUTHOR

Abstract

High syndiotactic polymethylmethacrylate is useful as an electron-beam (E-Beam) resist material. It can be prepared by anionic polymerizations which lend themselves to control of MW distribution, a characteristic which is also helpful in E-Beam technology. In addition, the syndiotactic PMMA has a high Tg which is desirable for resist materials. Its solubility characteristics make it useful for special techniques.

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Preparation of Highly Syndiotactic Polymethylmethacrylate

High syndiotactic polymethylmethacrylate is useful as an electron-beam (E- Beam) resist material. It can be prepared by anionic polymerizations which lend themselves to control of MW distribution, a characteristic which is also helpful in E-Beam technology. In addition, the syndiotactic PMMA has a high Tg which is desirable for resist materials. Its solubility characteristics make it useful for special techniques.

Most of the high syndiotactic, high MW PMMA is made by an organo lithium catalyst with an additive, which acts both as a chelating agent and a cocatalyst. Most of the cocatalysts belong to groups of compounds such as tetramethyl aliphatic diamines, alpha, omega-dimethoxyethyl ethers, N-methyl pyrrolidone, etc.

It has been found that 2-dimethylaminomethyl pyridine is a very effective cocatalyst and yields high syndiotactic PMMA. The polymerizations are instantaneous at -75 degrees C and the yields of polymer are nearly quantitative. The products contain from 5 to 10% more syndiotactic PMMA (uncorrected NMR) than those from similar polymerizations containing tetramethyl ethylene diamine, the most commonly used chelating agent.

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