Poly(silarylene–siloxane)polyimides from allyl‐terminated oligoimides and hydride‐functional silarylene–siloxanes via hydrosilylation polymerization

Abstract

This research was focused on the design and execution of new synthetic routes to low-temperature-curable poly(silarylene-siloxane)polyimides. The synthesis of individual oligoimide and silarylene-siloxane blocks was followed by hydrosilylation polymerization to produce crosslinked copolymers. The silarylene-siloxane and polyimide blocks were structurally characterized by IR and 1 H NMR spectroscopy and size exclusion chromatography. The high-temperature resistance of the copolymers was evaluated through the measurement of heat distortion temperatures (T HD 's) via thermomechanical analysis and by the determination of the weight loss at elevated temperatures via thermogravimetric analysis. Glass-transition temperatures (T g 's) of the silarylene-siloxane segments were measured by differential scanning calorimetry. Hydrosilylation curing was conducted at 60 8C in the presence of chloroplatinic acid (H 2 PtCl 6 ). The copolymers displayed both high-temperature resistance and low-temperature flexibility. We observed T g of the silarylene-siloxane segment as low as À77 8C and T HD of the polyimide segment as high as 323 8C. The influence of various oligoimide molecular weights on the properties of copolymers containing the same silarylene-siloxane was examined. The effect of various silarylene-siloxane molecular weights on the properties of copolymers containing the same oligoimide was also examined. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: [4922][4923][4924][4925][4926][4927][4928][4929][4930][4931][4932] 2005

Precursors for pyromellit-bridged silica sol–gel hybrid materials

“…Methods reported so far for the synthesis of bis(trialkoxysilylalkyl)pyromellitic diimide are hydrosilylation [22][23][24] and transimidation. [25][26][27] An alternative route, which has not been reported until now, is the first step of the Gabriel synthesis, a well-known method for the preparation of primary amines. 28,29 The Gabriel synthesis is based on the reaction of a potassium imide, generally potassium phthalimide, with alkyl halides to produce the alkylated imide and the potassium halide.…”

“…In the literature hydrosilylation and transimidisation were reported as possible routes to triethoxysilylalkylimide. [22][23][24][25][26][27] In the present study an approach based on the well-known Gabriel synthesis of amines is used for the preparation of bis(trialkoxysilylalkyl)imides.…”

Synthesis of a new siloxane‐containing alicyclic dianhydride and the derived polyimides with improved solubility and hydrophobicity

“…The incorporation of hydrophobic siloxane segments has been proved to be effective to increase the water ingression resistance of PIs in the past years 6–8. Considerable amount of works have researched the preparation of the siloxane‐containing PI from a siloxane‐containing dianhydride with an aromatic diamine,9 from a siloxane‐containing diamine with an aromatic dianhydride,10 or from the allyl‐terminated PI with a siloxane via hydrosilylation 11. Alternatively, introducing alicyclic segments to the main chain of PI could significantly increase the moisture resistance of PIs 12.…”

Hydrosilylation Polymerisation

“…6.31) [47][48][49][50]. An example is the reaction of linear dihydro polysiloxane with N,N'diallyldiimide in the presence of platinum cyclopentadiene complex [47]: (6.31) More recently poly(arylene-siloxylene)-polyimide thermoplastic elastomers have been synthesised through polyhydrosilylation of allyl-terminated oligoimides with α,ω-bis(hydro)silarylene-siloxanes in the presence of hexachloroplatinic acid or Karstedt's catalyst [51][52][53].…”