Organically modified ceramics and their applications

Schmidt, Helmut K.; Wolter, Herbert

doi:10.1016/0022-3093(90)90171-h

Cited by 228 publications

(96 citation statements)

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“…This is achievable by optimizing the processing parameters (temperature, catalyst and nature of the solvent) and by promoting reactions or interactions between the two components, either directly or via a coupling agent. Various methods for effectively introducing a silica phase into PI matrices have been reported by Nandi et al [17,22], Morikawa et al [7,11], Wang et al[23], Mascia et al [8,13], Schmidt and Wolter [24,25] among other. Given below is an account of some of the approaches used.…”

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confidence: 99%

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Polyimide/silica hybrids via the sol-gel route: High performance materials for the new technological challenges

Ragosta¹,

Musto²

2009

Express Polym. Lett.

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Abstract. The present review article describes in detail the state-of-the-art of organic-inorganic hybrid materials based on polyimide/silica components. The article is divided in three parts. In the first the basic processing route for the preparation of these systems is described, i.e. the sol-gel technique, along with the strategies developed to control the final morphology. In the second part the curing characteristics, the dynamic-mechanical and the mechanical and fracture properties of hybrids with different morphologies are reviewed. Finally, the more technologically relevant applications devised for these high performance materials are discussed. : nanocomposites, hybrid materials, polyimide, silica, sol-gel eXPRESS Polymer Letters Vol.3, No.7 (2009) [413][414][415][416][417][418][419][420][421][422][423][424][425][426][427][428] Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2009.51 or as functional materials [14] such as catalyst supports [15] and microelectronic devices [16]. The sol-gel route represents the preferred way for the synthesis of polyimide based hybrids. The classical sol-gel process consists in a two step hydrolysis-condensation reaction, starting with a metal alkoxides M(OR) 4 , typically tetraethoxisilane Si(OCH 2 CH 3 ) 4 or titanium isopropoxide Ti[OCH(CH 3 ) 2 ] 4 , to produce hydroxyl groups followed by the polycondensation of the hydroxyl groups and residual alkoxy groups to form a three-dimensional network [5,[17][18][19][20][21]. Polyimides are particularly suited for this type of process because they can be obtained from polyamic acid precursors, which are soluble in hygroscopic solvents and can, therefore, tolerate the addition of water necessary to bring about the hydrolysis of the metal alkoxide. Moreover, the outstanding thermal stability of polyimides allows the hybrids to be post-cured at very high temperatures (300-350°C) making it possible the development of a very dense inorganic network without inducing appreciable degradation of the organic phase. Polyimide/silica hybrids made by the sol-gel technique are the subject of this review, in which the approaches used for a close control of their final morphology, the effects of the silica phase on the curing process of polyimide precursors, the dynamic-mechanical and the mechanical and fracture properties that these materials can display, and their possible applications will be presented and discussed. Keywords Processing and morphologyA typical procedure for the preparation of PI/silica hybrids via the sol-gel route, involves the following steps: i) The polyamic acid (PAA) (PI precursor) is formed by a polyaddition reaction of a dianhydride [e.g., pyromellitic anhydride (PMDA), 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA), or 2,2-bis(3,4-dicarboxy-phenyl)-hexafluoropropane dianhydride (6FDA)] with a diamine [e.g., 4,4′-oxydianiline (ODA), or p-phenylen diamine (PPA)] in a common solvent [e.g., dimethylacetamide (DMAc), or N-methyl pyrolidone (NMP)]. The reaction and chemical str...

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“…[23], Mascia et al [8,13], Schmidt and Wolter [24,25] among other. Given below is an account of some of the approaches used.…”

mentioning

confidence: 99%

Polyimide/silica hybrids via the sol-gel route: High performance materials for the new technological challenges

Ragosta¹,

Musto²

2009

Express Polym. Lett.

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“…The electrical conductivity of P(2VP-co-MMA) with the molar ratio of 2VP/MMA ¼ 1:1 was widely controlled with the amount of doped Co(CH 3 COO) 2 . 54 The electrical properties of P(2VP-co-MMA) and their organic-silica nanocomposites are listed in Table 1.…”

Section: Electrical Properties Of the Compositesmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] Application of organic-silica nanocomposite depends on the synthetic method because structure of silica, which effects on the properties, depends on the synthetic method. One of the useful and convenient methods to prepare the composite is a sol-gel method.…”

Section: Introductionmentioning

confidence: 99%

“…The major advantages of the sol-gel method are not only its convenience, but also lower reaction temperature than decomposition temperature of organic polymer and high applicability to many kind of organic polymers. 2,3,9,[15][16][17][18] For example, poly(meth)acrylates, polystyrene blended with silica were prepared by the sol-gel method. However, silica prepared by the sol-gel method contains a lot of lattice defects, which reduce transparency, mechanical strength, etc.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and properties of organic‐silica nanocomposites with perhydropolysilazane

Saito

2006

J. Polym. Sci. A Polym. Chem.

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ABSTRACT:The synthesis and properties of the organic polymersilica nanocomposites by blending perhydropolysilazane with organic polymer having hydroxyl groups have been described. Poly(methyl methacrylate) (PMMA)-silica nanocomposites with a PMMA/silica lamellar structure and spherical silica domains in a PMMA matrix were obtained with random copolymers and block copolymers. The effect of the architecture of the random and block copolymers on the morphology of composites has been summarized. The thermal stability, electrical properties, such as field break down, leakage current, etc., and surface hardness of the composites have been discussed.

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Dependence of silica particle sizes on network chain lengths, silica contents, and catalyst concentrations inin situ-reinforced polysiloxane elastomers

Breiner

Mark

Beaucage

1999

J. Polym. Sci. B Polym. Phys.

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Organically modified ceramics and their applications

Cited by 228 publications

References 3 publications

Polyimide/silica hybrids via the sol-gel route: High performance materials for the new technological challenges

Polyimide/silica hybrids via the sol-gel route: High performance materials for the new technological challenges

Synthesis and properties of organic‐silica nanocomposites with perhydropolysilazane

Dependence of silica particle sizes on network chain lengths, silica contents, and catalyst concentrations inin situ-reinforced polysiloxane elastomers

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