Synthesis and Characterization of Semiaromatic Polyimides Containing POSS in Main Chain Derived from Double-Decker-Shaped Silsesquioxane

Abstract

A series of semiaromatic polyimides containing polyhedral oligomeric silsesquioxane (POSS) in main chain (POSS−PIs) from a double-decker-shaped silsesquioxane diamine (DDSQ−diamine) (4) with various aromatic tetracarboxylic dianhydrides were prepared and the structures were characterized by IR and NMR spectra. A double-decker-shaped silsesquioxane dianhydride (DDSQDA) (3) was synthesized by hydrosilylation reaction from double-decker-shaped silsesquioxane (DDSQ) (1) and cis-5-norbornene-endo-2,3-dicarboxylic anhydride (2), which then reacted with 4,4‘-oxydianiline (ODA) to produce the DDSQ-diamine. The POSS−PIs possessed good thermal stability and mechanical properties, low water absorption, and alkali resistance as well as low dielectric constant. The 5% weight loss temperatures (T d 5) in air were observed at 495−514 °C. The polymer films had good mechanical properties with elongation at breakage of 2.9−6.0%, in which POSS−PI 8c derived from 4,4‘-oxydiphthalic anhydride (ODPA) exhibits the highest elongation of 6.0%. The water absorption of POSS−PI 8b (<1%) was much lower than that of PI from pyromellitic dianhydride (PMDA)/ODA (6.0%). POSS−PIs 8 possessed excellent alkaline and acid resistance. POSS−PI 8b kept its flexible mechanical properties when immersed in 5% NaOH solution at 40 °C for 72 h. The dielectric constant of POSS−PI 8c measured by precision impedance method was 2.36.

Thermodynamic study of POSS-based ionic liquids with various numbers of ion pairs

“…[17][18][19][20][21][22][23][24] In polar solvents, POSS can form a globular conformation and create a distinct hydrophobic space around the POSS core. [25][26][27][28] Such structural features can contribute to reduce the packing density and isolating the distal ion pairs.…”

Synthesis and characterization of new liquid, branched and random poly(methylhydrosiloxanes)

“…4 , containing two kinds of functional groups, can be thermally self-cured, and the octafunctional derivative can be copolymerized with hydrosiloxanes (by hydrosilylation reaction) to give transparent organic-inorganic hybrid nanocomposites with good thermal stability (up to ≥400 °C in air) [161]. 5,11,14,17-tetra(hydrodimethylsiloxy)octaphenylcyclooctasilsesquioxane (double-decker type) which was synthesized similarly as (PhSiO 1.5 ) 8 (MeHSiO) 2 [from an appropriate tetra(sodiosilanolate) precursor and chlorodimethylsilane in THF] was used as a rigid siloxane core for a preparation of liquid crystalline solid material [90] and semiaromatic polyimides containing silsesquioxane moieties in a main chain [162] 4 , and a multifunctional hydride Q resin were also used for the same purpose [90].…”

Multi-Alkenylsilsesquioxanes as Comonomers and Active Species Modifiers of Metallocene Catalyst in Copolymerization with Ethylene

“…Di-functional POSS derivatives have attracted considerable attention in recent years. Depending on the types of reactive substituents, they have been successfully incorporated into such macromolecules as polyimide [9][10][11], polysiloxane [12], polyamide [13], polyurethane [14], polysulfone [15], vinylidene-arylene copolymer [16], and polyethylene [17], via the polyethylene [17], via the step-growth polymerization process [9][10][11][13][14][15][16]18], or as pendant groups and cross-linkage sites through the coordination copolymerization [17].…”