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Condensation polymerization of multifunctional monomers and properties of related polyester resins. I. Polyester varnishes
Author(s) -
Chiang WenYen,
Chiang WenChang
Publication year - 1988
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1988.070350602
Subject(s) - condensation polymer , polyester , monomer , materials science , polymer chemistry , polymerization , pentaerythritol , thermogravimetric analysis , catalysis , thermal stability , ethylene , ethylene glycol , dimethyl terephthalate , polymer , organic chemistry , chemistry , fire retardant , composite material
This article discusses optimum conditions for polycondensation of multifunctional monomers. Reaction variables such as monomer concentration, temperature, and time were studied to optimize reaction conditions. The influence of the nature and concentration of catalysts was also investigated. The optimum reaction conditions consisted of polymerization in an 82% w/w m ‐cresol solution at 160°C for 2 h, continuous reaction at 200°C for 1.5 h at 230°C for 3.5 h, followed by 40 min under reduced pressure and at 200°C. The catalyst was 1.4 × 10 −3 mol % Zn(OAc) 2 · 2H 2 O in dimethyl terephthalate. Polycondensation of ethylene glycol, 1,4‐butanediol, pentaerythritol, and trifunctional monomers (glycerin or trimethanolpropane) with dimethyl terephthalate was carried out in m ‐cresol to produce polyester prepolymers. The synthesized prepolymers were mixed with commercial Desmodur CT‐stable (a phenol‐blocked polyisocyanate) to form one‐component varnishes which were characterized by thermogravimetric analysis. Polyester modified with trimethanolpropane has higher thermal stability than the one modified with glycerin. After being coated onto treated copper wires, the magnetic wires were characterized according to the specification of Japanese Industrial Standards (JIS‐C‐2358) and were found to be acceptable.