Preparation of Polyimide Particles by Precipitation Polymerization.

Asao, Katsuya; Ohnishi, Hitoshi; Morita, Hitoshi

doi:10.1295/koron.57.271

Cited by 9 publications

(6 citation statements)

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“…Several kinds of highly crystalline polyimide particles were obtained by heating poly(amic acid) solutions at 180 C as the result of thermal imidization of poly(amic acid)s in N-methyl-2-pyrrolidone. 87,88 The morphology of the particles was a sheaf or coral that was similar to spherulites of the polymer and they were found to be highly crystalline particles. The size of the particles was in the range from 1 mm to 10 mm.…”

Section: Morphology Control Of Aromatic Polymersmentioning

confidence: 99%

Morphology Control of Aromatic Polymers in Concert with Polymerization

Kimura

Kohama

Yamazaki

2006

Polym J

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ABSTRACT:Morphology control methods of aromatic polymers in concert with polymerization reaction are described in this review. Many attractive methods have been developed including reaction-induced phase separation of oligomers, epitaxial polymerization, shear-induced chain orientation during gelation, template-based polymerization, suspension polycondensation, solid-state polycondensation and liquid-liquid interfacial precipitation and so on. Among them, the reaction-induced phase separation of oligomers, in which there are two modes of crystallization and liquidliquid phase separation, possess practically high potentiality to create novel polymer materials since it can control not only the morphology but also the molecular chain orientation. Ultimate goal is the embodiment of the nature system in a flask, that is, the control of the materials from primary structures to super structures. The morphology control methods by using polymerization reaction afford the valuable methodology for the three-dimensional structure architecture.[doi:10.1295/polymj.PJ2006083] KEY WORDS Morphology / Phase Separation / Oligomer / Whisker / Microsphere / Epitaxy / Aromatic Polymer / Morphology of polymer materials is of great importance as well as the molecular chain orientation for the creation of new functional and high-performance materials possessing essential properties predicted from their molecular structures. From the both aspects of molecular chain orientation and morphology, one of the ideal materials is a needle-like single crystal of extended molecular chains called polymer whisker. Especially, wide variety of polymeric nanomaterials is required for supporting nanotechnology and the more precise controls are rapidly necessitated in these days. Hence, the demand for the morphology control method increases significantly. Usually, extended molecular chain crystals are difficult to obtain by conventional processing methods and the special processing techniques have been developed thus far.1 There exists another stream for the development of extended molecular chain crystals by means of crystallization during polymerization. The needle-like crystals of both flexible and rigid polymers have been obtained by the solid-state polymerization of the monomers and the polymerization in the solution. Examples of the former polymerization have included oxacyclobutanes such as 1,3,5-trioxane, 2,3 diolefins undergoing four-center type photopolymerization 4,5 and monomers with conjugated triple bonds such as substituted diacetylenes.6,7 On the other hand, the first polymer whisker was obtained by the cationic ring-opening polymerization of 1,3,5-trioxane. [8][9][10] The obtained polyoxymethylene whiskers were 1-2 mm in width and 10-50 mm in length. The molecular chains aligned along the long axis of the whisker. They were brought into practical uses with its unique morphology and good mechanical properties.11,12 However, the polyoxymethylene whisker has a melting temperature at 180 C and the low melting temperature limits the broader c...

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Section: Morphology Control Of Aromatic Polymersmentioning

confidence: 99%

Morphology Control of Aromatic Polymers in Concert with Polymerization

Kimura

Kohama

Yamazaki

2006

Polym J

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“…Among the numerous available polyimides, poly( p-phenylenepyromelliteimide) (PPPI) is among those with best performance due to its rigid-rod structure. [1] Micro-sized polyimide spheres have attracted much attention in view of their potential as new high-performance materials, [2][3][4][5][6][7][8] surface-modifiers, [9][10][11] microcapsules, [12,13] textile modifiers, spacers for display, chromatographic carriers [14][15][16] and so on. Spheres with rugged surfaces have quite large surface areas and small pores, and receive therefore much attention as potential new functional fillers, carriers, adsorbents and so on.…”

Section: Introductionmentioning

confidence: 99%

“…The solution spraying method [17] and polymer grinding method [18] are well-known, but microspheres prepared by these methods tend to form agglomerates and their size distribution is quite broad. Polyimide microspheres have also been prepared by a precipitation method during thermal imidization of poly(amic acid)s. [6][7][8][9] We studied the preparation of polyimide microspheres using the phase separation during isothermal polymerization. The phase separation during isothermal polymerization is not limited by the intractability of polymers, and it is a suitable method especially for poorly processable polymers.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Poly(p‐phenylenepyromelliteimide) Microspheres with Rugged Surfaces Using Crystallization During Isothermal Polymerization

Wakabayashi

Uchida

Yamazaki

et al. 2010

Macro Chemistry & Physics

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Preparation of discrete PPPI microspheres was examined using the crystallization of oligomers during isothermal polymerization of PMDA and p‐phenylene diisocyanate, and that of pyromellitic dithioanhydride and PPDA in poor solvents. In contrast to PPPI microspheres with smooth surfaces that were previously prepared by phase‐separation during the polymerization of PPDA and PMDA, the microspheres obtained here consisted of flake‐like lamellae with rugged surfaces. The diameters of the microspheres ranged from 0.5 to 6.7 µm. They exhibited excellent thermal stability depending on the monomers. These results provide a new preparative procedure of the PPPI microsphere with a rugged surface. magnified image

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“…10,11 Minami et al, for example, prepared PPSQ particles with an average diameter of 0.2-1.0 µm and a relatively wide size distribution from organoalkoxysilane. They used these microparticles for preparing the thick films of PPSQ and applied as micro-optical devices.…”

Section: Introductionmentioning

confidence: 99%

Formation of Stable Nanoparticles of Poly(phenyl/methylsilsesquioxane) in Aqueous Solution

Taniguchi

Miyamoto

et al. 2003

Polym J

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ABSTRACT:Nanoparticles of poly(phenyl/methylsilsesquioxane) (PPMSQ) were prepared by emulsion polymerization of the co-hydrolysate that had been formed from a mixture of trichlorophenylsilane (TCP) and trichloromethylsilane (TCM) in aqueous solution. The average size of the resultant particles was controlled from 30 to 250 nm in diameter by changing the initial concentration of the co-hydrolysate and the amount of the emulsifier added. The PPMSQ formed from the hydrolysate of TCP/TCM had a high cross-linking density, being insoluble and stable in nature. The 1 H NMR spectrum of the co-hydrolysate revealed that both the primary hydrolysates of TCP and TCM are involved in the fast co-polycondensation to afford meta-stable water-soluble oligomers having many silanol groups. These oligomers are allowed to react with each other to form the nanoparticles with the aid of emulsifier.KEY WORDS Polysilsesquioxane / Nanoparticles / Emulsion Polymerization / Trichlorophenylsilane / Trichloromethylsilane / Polysilsesquioxanes (PSQ) with the formula of (RSiO 3/2 ) n are a family of silicone compounds having outstanding thermal stability and good electric insulating properies. [1][2][3] In general, PSQ can be obtained by the hydrolytic polycondensation of trifunctional monomers, RSiX 3 , where X can be a halide, an alkoxide, or a carboxylate. Their typical examples are poly(phenylsilsesquioxane) (PPSQ) and poly(methylsilsesquioxane) (PMSQ) that are synthesized from phenyltrichlorosilane (TCP) 4 and methyltrichlorosilane (TCM), 5 respectively. Recently, we reported that the hydrolysis of TCP in an aqueous/organic bilayer system produces monomeric phenylsilanetriol (PST) in the aqueous layer and that the KOH-catalyzed polycondensation of this PST in refluxing toluene gives rise to PPSQ with highly ordered ladder structure. 6,7 More recently, we conducted the polycondensation of the TCP hydrolysate in a refluxing toluene/water bilayer system with the aid of a phase transfer catalyst to obtain PPSQ in high yield without passing the isolation step of the TCP hydrolysate. 8 We also disclosed the preparation of nanoparticles of PPSQ having an average diameter of 30-110 nm by conducting the emulsion polymerization of the TCP hydrolysate after the addition of an emulsifier. 9 This was the first success in preparing the nanoparticles of PSQ.With increasing interest in designing micro-and nano-structured materials for industrial needs, many attempts have been made to obtain particles with suitable size and shape. 10,11 Minami et al., for example, prepared PPSQ particles with an average diameter of 0.2-1.0 µm and a relatively wide size distribution from organoalkoxysilane. They used these microparticles for preparing the thick films of PPSQ and applied as micro-optical devices. 12 Nota et al. prepared the PMSQ particles with an average diameter of 0.2-5.0 µm by emulsion polymerization of organoalkoxysilane. 13,14 Our former success in preparing the PPSQ nanoparticles has opened a new option in designing the nano-structured materials.The p...

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Preparation of Polyimide Particles by Precipitation Polymerization.

Cited by 9 publications

References 0 publications

Morphology Control of Aromatic Polymers in Concert with Polymerization

Morphology Control of Aromatic Polymers in Concert with Polymerization

Preparation of Poly(p‐phenylenepyromelliteimide) Microspheres with Rugged Surfaces Using Crystallization During Isothermal Polymerization

Formation of Stable Nanoparticles of Poly(phenyl/methylsilsesquioxane) in Aqueous Solution

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