Polyimide nanocomposites mechanical properties

Thompson, D.S., Thompson, D.W., and Southward, R.E. (2002) Oxo-metal-polyimide nanocomposites. 2 enhancement of thermal mechanical and chemical properties in soluble hexafluoroisopropyUdene-based poly-imides via the in situ formation of oxo-lanthanide(III)-polyimide nanocomposites. Chemistry of Materials, 14,... 

H.-L. Tyan, C.-M. Liu, and K.-H. Wei, Effect of reactivity of organics-modified montmorillonite on the thermal and mechanical properties of montmorillonite/polyimide nanocomposites. Chemistry of Materials, 13 (2001), 222-6. 

H.-L. Tyan, K.-H. Wei, and T.-E. Hsieh, Mechanical properties of clay-polyimide (BTDA-ODA) nanocomposites via ODA-modified organoclay. Journal of Polymer Science, Part B Polymer Physics, 38 (2000), 2873-8. 

V. E. Yudin, J. U. Otaigbe, V. M. Svetlichnyi, E. N. Korytkova, O. V. Almjasheva, V. V. Gusarov, Effects of nanofiller morphology and aspect ratio on the rheo-mechanical properties of polyimide nanocomposites, eXPRESS Polymer Letters, 2 (2008), 485-93. 

The preparation of polyimide-montmorillonite nanocomposites presents challenges that are unique compared with the constraints associated with the polymers discussed above. Polyimides are utilized in the aerospace industry because of their balance of mechanical properties and high thermal stability. Polyimides have found value in the electronic packaging and insulation industrial because of the additional quality of electrical insulation. 

Commercial membranes for CO2 removal are polymer based, and the materials of choice are cellulose acetate, polyimides, polyamides, polysulfone, polycarbonates, and polyeth-erimide [12]. The most tested and used material is cellulose acetate, although polyimide has also some potential in certain CO2 removal applications. The properties of polyimides and other polymers can be modified to enhance the performance of the membrane. For instance, polyimide membranes were initially used for hydrogen recovery, but they were then modified for CO2 removal [13]. Cellulose acetate membranes were initially developed for reverse osmosis [14], and now they are the most popular CO2 removal membrane. To overcome state-of-the-art membranes for CO2 separation, new polymers, copolymers, block copolymers, blends and nanocomposites (mixed matrix membranes) have been developed [15-22]. However, many of them have failed during application because of different reasons (expensive materials, weak mechanical and chemical stability, etc.). 

Until 2003, Chen s [28], Qu s [29-31], and Hu s [32] groups independently reported nanocomposites with polymeric matrices for the first time the. In Hsueh and Chen s work, exfoUated polyimide/LDH was prepared by in situ polymerization of a mixture of aminobenzoate-modified Mg-Al LDH and polyamic acid (polyimide precursor) in N,N-dimethylactamide [28]. In other work, Chen and Qu successfully synthesized exfoliated polyethylene-g-maleic anhydride (PE-g-MA)/LDH nanocomposites by refluxing in a nonpolar xylene solution of PE-g-MA [29,30]. Then, Li et al. prepared polyfmethyl methacrylate) (PMMA)/MgAl LDH by exfoliation/adsorption with acetone as cosolvent [32]. Since then, polymer/LDH nanocomposites have attracted extensive interest. The wide variety of polymers used for nanocomposite preparation include polyethylene (PE) [29, 30, 33 9], polystyrene (PS) [48, 50-58], poly(propylene carbonate) [59], poly(3-hydroxybutyrate) [60-62], poly(vinyl chloride) [63], syndiotactic polystyrene [64], polyurethane [65], poly[(3-hydroxybutyrate)-co-(3-hydroxyvalerate)] [66], polypropylene (PP) [48, 67-70], nylon 6 [9,71,72], ethylene vinyl acetate copolymer (EVA) [73-77], poly(L-lactide) [78], poly(ethylene terephthalate) [79, 80], poly(caprolactone) [81], poly(p-dioxanone) [82], poly(vinyl alcohol) [83], PMMA [32,47, 48, 57, 84-93], poly(2-hydroxyethyl methacrylate) [94], poly(styrene-co-methyl methacrylate) [95], polyimide [28], and epoxy [96-98]. These nanocomposites often exhibit enhanced mechanical, thermal, optical, and electrical properties and flame retardancy. Among them, the thermal properties and flame retardancy are the most interesting and will be discussed in the following sections. 

So HH, Cho JW, Sahoo NG. Effect of carbon nanotubes on mechanical and electrical properties of polyimide/carbon nanotubes nanocomposites. Eur Polym J 2007 43 3750-3756. 

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