ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
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 · 2H2O 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.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1988.070350602
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