A Novel Technology To Synthesis Of Macromonomer Polyethylene Glycol Monoethyl Ether Methacrylate

Polyethylene glycol monoethyl ether methacrylate (PEGMEMA) is an important macromonomer for synthezing new functional materials. The comblike amphiphilic copolymers prepared from this macromonomer can be widely used such as, drug carrier, environmental friendly coatings, cement reducer. Polycarboxylic acid type water-reducer containing this copolymer component is characterized with many advantages. At present, the traditional process of preparing PEGMEMA includes two steps, firstly, Polyethylene glycol monoether is synthezised by adding ethylene oxide to methanol or ethanol with sodium as catalyst under the condition of high temperature and high pressure; then, Polyethylene glycol monoether reacts with methacrylic acid or methacrylate in organic solvent. The traditional techniches of preparing PEGMEMA is complicated and has some problems such as its equal molar ratio comsumption of sodium and hydrogen release,using a large amount of acid in neutralization as well as solvent recovery. Those defects limited the application of the macromonomer. Therefore, the research and development of a new PEGMEMA synthetic technology is of great significance, and this is precisely the main content of this article.A novel process to synthesize macromonomer polyethylene glycol monoethyl ether methacrylate (PEGMEMA) was investigated. PEGMEMA was obtained by transesterification of polyethylene glycol monoethyl ether acetate (PEGMEA) with ethyl methacrylate (EMA) in the presence of catalyst and polymerization inhibitor. The intermediate (PEGMEA) was prepared by directly inserting ethylene oxide into ethyl acetate. The main contents of this paper are as follows:1,A series of Al-Mg composite oxide catalysts(series of AM catalysts) were optimized for preparing polyethylene glycol monoethyl ether acetate(PEGMEA) by means of catalysizing one-step ethoxylation of ethyl acetate. The product was characterized by FT-IR and ESI-MS. The optimum catalyst for ethoxylation of ethyl acetate were screened out. It was found that the catalyst, AM4, has the highest catalytic activity for preparing PEGMEA.2,The screening of the catalyst and polymerization inhibitor, the influences of the dosage of catalyst, the molar ratio of reactants, reaction temperature and time on the transesterification were investigated. The product was analyzised by FT-IR, UV, together with GC. It was found that tetra-n-butyltitanate (TBOT) and 2,2,6,6-tetramethyl-1-Piperidinyloxy (TEMPO) possess the highest catalytic activity and the most effective polymerization inhibition respectively among the other tested catalysts and polymerization inhibitors. The optimal conditions were as following: TBOT as catalyst , TEMPO as polymerization inhibitor, n(PEGMEA):n(EMA)=1:3, w(TBOT)= 7%, w(TEMPO)=0.1% ,130℃and 3h, giving a yield of PEGMEMA of 88.7%.