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Effects of monomer addition sequences on the properties of silicon‐containing copolyimides
Author(s) -
Ren Li,
Li GL,
Shen Jiarui,
Jia Demin
Publication year - 2005
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.1824
Subject(s) - thermogravimetric analysis , monomer , materials science , thermal decomposition , tetrahydrofuran , molar ratio , silicon , pyromellitic dianhydride , polymer chemistry , dielectric , benzene , catalysis , organic chemistry , chemistry , solvent , polyimide , polymer , composite material , layer (electronics) , metallurgy , optoelectronics
A series of silicon‐containing copolyimides was synthesized by the reaction of 4,4′‐diaminodiphenylmethane (DDM) with 1,4‐bis(3‐aminopropyldimethylsilyl) benzene (BisB) and pyromellitic dianhydride (PMDA). The synthesis reactions of the copoly(amic acid)s were carried out by three different monomer addition sequences under different molar ratios of BisB to DDM. The results obtained show that the viscosity of the poly(amic acid) (PA) solution obtained by the addition sequence of DDM–PMDA–BisB is higher than those of the other two addition sequences (ie [DDM + BisB]–PMDA and BisB–PMDA–DDM) and decreases as the molar ratio of BisB to DDM increases. Copolyimides formed by different addition orders, but with the same BisB to DDM molar ratios, possess different properties, such as dielectric constant, water absorption and contact angle. All of these copolyimides were insoluble in common organic solvents such as N ‐methyl‐2‐pyrrolidinone and tetrahydrofuran. Thermogravimetric analysis (TGA) show that the silicon‐containing copolyimides have excellent thermal properties and their decomposition temperatures for an 8 % weight loss decrease slightly as [BisB]/[DDM] increases. Copyright © 2005 Society of Chemical Industry