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Polymerization of benzoguanamine and pyromellitic dianhydride under microwave radiation and its third‐order optical nonlinearities
Author(s) -
Lu Jianmei,
Chen Naiyong,
Ji Shunjun,
Sun Zhenrong,
Ding Meixiang,
Zhu Xinlin
Publication year - 2001
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.1972
Subject(s) - pyromellitic dianhydride , microwave , polyimide , monomer , polymerization , polymer chemistry , materials science , condensation polymer , polymer , analytical chemistry (journal) , chemistry , physics , organic chemistry , nanotechnology , composite material , layer (electronics) , quantum mechanics
Polycondensation and imidization of benzoguanamine and pyromellitic dianhydride under microwave radiation were studied. The effects of the microwave radiation time (power), the composition of the monomer on the imidization, and the polymer yield were discussed. The polycondensates' third‐order optical nonlinearities and time responses were measured by a phase conjugate forward, 3‐dimensional degenerate, four‐wave mixing technique. At the same time they were compared with relevant conventional thermopolymerization. The results showed that the polycondensates had high third‐order nonlinear optical coefficients [polyimide (PI) χ (3) = 1.181 × 10 −13 esu] and fast time responses (22 ps). The third‐order nonlinear optical coefficients under microwave radiation were higher than that of conventional thermopolymerization (microwave radiation PI χ (3) = 1.181 × 10 −13 esu: thermopolymerization PI χ (3) = 0.686 × 10 −13 esu). The experimental results also showed that the third‐order optical nonlinearities were not only affected by the length of the polycondensate chain, but also the polycondensate π‐electron density distribution, which was explained and confirmed by computation with the semiempirical Austin method. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1356–1363, 2001