کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1396355 | 984173 | 2009 | 12 صفحه PDF | دانلود رایگان |
A series of new polyimides (PIs) containing di-tert-butyl side groups were synthesized via the polycondensation of 4-(4-amino-2-chlorophenyl)-1-(4-aminophenoxy)-2,6-di-tert-butylbenzene (3) with various aromatic tetracarboxylic dianhydrides. The introduction of the asymmetric di-tert-butyl groups and twisted-biphenyl structures is an effective way to increase the inter chain distance and decrease the intermolecular interaction and packing ability of the resulted polymers. Thus, these novel PIs exhibited low dielectric constants (2.83–3.10), low moisture absorption (0.95–1.69%), excellent solubility, and high glass transition temperatures (307–456 °C). The PIs derived from the new diamine and the rigid pyromellitic dianhydride (PMDA) were soluble in N-methyl-2-pyrrolidinone, N,N-dimethylacetamide, tetrahydrofuran, m-cresol, and cyclohexanone. The polymers also show good retention of storage modulus at high temperature (325 °C). In addition, 1H NMR spectrum of the diamine 3 revealed that the protons of 4-aminophenoxy moiety are not chemical shift equivalent.
Journal: European Polymer Journal - Volume 45, Issue 4, April 2009, Pages 1127–1138