caa a22 4500 463222555 CHVBK 20180405153217.0 cr unu---uuuuu 170326e20071001xx s 000 0 eng 10.1007/s10853-006-1072-x doi (NATIONALLICENCE)springer-10.1007/s10853-006-1072-x The effect of curing conditions and ageing on the thermo-mechanical properties of polyimide and polyimide-silica hybrids [Elektronische Daten] [Ahmad Ali, Z. Ahmad] The effect of curing conditions and ageing on the thermo-mechanical properties of polyimide and its ceramers has been studied. Polyamic acid (PAA), a polyimide precursor, was prepared by the well known reaction of pyromellitic dianhydride and oxydianiline in dimethylacetamide as solvent. The silica network was developed in PAA solution by hydrolysis and condensation of tetraethoxysilane. The pure PAA films and those with 25wt% silica content were imidized by six different curing protocols involving both step-wise and isothermal heatings. The dynamic mechanical thermal (DMTA) and thermal mechanical analyses (TMA) were performed on the pure and ceramer films cured under the different imidization conditions. The data for the mechanical properties were obtained for the same films left over for a year. The variations of storage and loss moduli and the glass transition temperature associated with α-relaxation and the linear thermal expansion coefficient have been explained in terms of degree of imidization and the effect of silica network densification under different conditions as a result of imidization and ageing. Springer Science+Business Media, LLC, 2007 Ali Ahmad Department of Chemistry, Kuwait University, P. O. Box 5969, 13060, Safat, Kuwait aut Ahmad Z. Department of Chemistry, Kuwait University, P. O. Box 5969, 13060, Safat, Kuwait aut Journal of Materials Science Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 42/19(2007-10-01), 8363-8369 0022-2461 42:19<8363 2007 42 10853 https://doi.org/10.1007/s10853-006-1072-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10853-006-1072-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ali Ahmad Department of Chemistry, Kuwait University, P. O. Box 5969, 13060, Safat, Kuwait aut NATIONALLICENCE 700 1- Ahmad Z. Department of Chemistry, Kuwait University, P. O. Box 5969, 13060, Safat, Kuwait aut NATIONALLICENCE 773 0- Journal of Materials Science Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 42/19(2007-10-01), 8363-8369 0022-2461 42:19<8363 2007 42 10853 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer