Self-Organizing Polycondensation of (<i>E</i>)-4-Acetoxycinnamic Acid for Preparation of Poly(<i>p</i>-oxycinnamoyl) Microspheres

Kimura, Kunio; Inoue, Hiromasa; Kohama, Shin Ichiro; Yamashita, Yuhiko; Sakaguchi, Yoshimitsu

doi:10.1021/ma030197q

Cited by 35 publications

(25 citation statements)

References 26 publications

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“…Polymerizations of (E)-4-acetoxycinnamic acid were car- ried out under various conditions. 77 Polymerization in liquid paraffin yielded the microspheres of poly-(p-oxycinnamoyl) (POC) having a smooth surface at 270-330 C. The average diameter was 4.6 mm, as shown in Figure 9a. When the polymerization was carried out at 310 C in Therm S 800 and 300 C in Therm S 900 (a mixture of hydrogenated terphenyl, Nippon Steel Chemical Co. Ltd.), the microspheres were also obtained, of which the average diameter was 3.9 and 3.3 mm, respectively.…”

Section: Reaction-induced Liquid-liquid Phase Separationmentioning

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: Reaction-induced Liquid-liquid Phase Separationmentioning

confidence: 99%

Morphology Control of Aromatic Polymers in Concert with Polymerization

Kimura

Kohama

Yamazaki

2006

Polym J

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“…On the other hand, if precipitated across the consolution curve, microdroplets are formed via liquid-liquid phase separation and microspheres are finally obtained as previously reported. 19,20 The polymerization of AMBA yields the PMB whiskers formed via the crystallization of oligomers as aforesaid. Other monomers afford only the microspheres and the spherical morphology indicates that these microspheres are obtained via the formation of microdroplets by liquidliquid phase separation of oligomers and further polymerization in them.…”

Section: Polymerization Of S-acyl-4-mercaptobenzoic Acidsmentioning

confidence: 99%

Morphology Control of Poly(p-mercaptobenzoyl) by Modification of Oligomer End-group

Kimura

Nakajima

Kobashi

et al. 2005

Polym J

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ABSTRACT:Influence of acyl end-group of oligomers on morphology of poly(p-mercaptobenzoyl)(PMB) was examined by the polymerization of S-acyl-4-mercaptobenzoic acids having the different acyl groups and their dimers in liquid paraffin at 260-300 C. The polymerization of S-acetyl-4-mercaptobenzoic acid afforded PMB whiskers, whereas the polymerization of S-propionyl-4-mercaptobenzoic acid, S-butyryl-4-mercaptobenzoic acid and S-valeryl-4-mercaptobenzoic acid yielded PMB microspheres. The microspheres were formed by the liquid-liquid phase separation of oligomers induced by the longer acyl end-groups than acetyl group of the oligomers due to the reduction of freezing point of oligomers. In contrast to this, the polymerizations of their dimers afforded needle-like and slab-like crystals instead of microspheres. In these polymerizations, the crystallization was induced due to the increase of the molecular weight of the phase-separated oligomers, leading to the increase of the freezing point of oligomers. The morphology of PMB could be controlled by the chemical modification of oligomer end-groups. [DOI 10.1295/polymj.37.471] KEY WORDS Poly(p-mercaptobenzoyl) / Morphology / Whisker / Microsphere / Oligomer / Phase Separation / End-group / Performance and functionality of polymeric materials are usually governed by not only polymer structure but also morphology including polymer chain alignment, and therefore morphology control is of great importance to withdraw the potentiality expected from the polymer structure. Wholly aromatic polymers have been receiving considerable attention as hopeful candidates for high performance and functional polymeric materials due to their excellent properties such as thermal stability, mechanical properties, solvent resistance, optical properties and so on. However, many of them exhibit neither solubility nor fusibility due to their rigid structures. The relationship between the property and the processability is trade-off and many efforts have been made to overcome this antagonistic problem from the aspect of not only chemical modification of polymer structures 1 but also processing techniques. 2 We have been studying morphology control of rigid aromatic polymers during solution polymerization and succeeded in preparing the whiskers of poly(pmercaptobenzoyl) (PMB) 3,4 and other aromatic polyesters. [5][6][7][8][9][10][11][12] The PMB whiskers are prepared by the polymerization of S-acetyl-4-mercaptobenzoic acid (AMBA) in liquid paraffin (LPF) at 300 C. The polymer chains are aligned along the long axis of the whiskers and the whiskers show single crystal nature.The formation mechanism of the whisker contains following steps. Oligomers are precipitated from the solution to form lamellae, when molecular weight of oligomers exceeds a critical value. The lamellae pile up in the form of needle-like crystals with spiral growth. Solid-state polymerization occurs in the needle-like oligomer crystals and the whiskers consisted of high molecular weight extended polymer chains are eventually ...

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“…15,16 When the polymerization is performed in the solvent which is good to monomers and poor to polymers, phase separation is induced by the increase in the molecular weight of oligomers formed in the solution. When the crystallization occurs, the oligomers are precipitated to form the crystals and the following polymerization proceeds in the precipitated crystals with maintaining the morphology.…”

Section: Introductionmentioning

confidence: 99%

“…The morphology is built by means of the phase separation during polymerization, and therefore this method is no longer limited by the intractability of polymers. With respect to the spherical morphology, microspheres 15 and those having needle-like crystals 16 have also been prepared by the reaction-induced liquid-liquid phase separation. Many of the high-performance polymers are usually synthesized by the polycondensation reaction that proceeds with eliminating small molecules.…”

Section: Introductionmentioning

confidence: 99%

Hollow spheres of aromatic polyamide prepared by reaction‐induced phase separation

Fujitsu

Nakayama²,

Uchida

et al. 2012

J. Polym. Sci. A Polym. Chem.

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Hollow spheres of aromatic polyamide are obtained by the reaction-induced phase separation during polymerization of 5-hydroxyisophthalic acid and 1,4-phenylene diamine in an aromatic solvent at a concentration of 1-2% at 320 C without stirring. The hollow sphere has a dimple hole and the diameters of the hollow spheres are 3-4 lm. The droplets are initially generated via liquid-liquid phase separation and then rigid crosslinked network structure formed the rigid skin layer on the surface of the droplets. The solidification of the droplets occurred owing to the further polymerization in them with maintaining the morphology to form the hollow spheres. The hollow spheres exhibit outstanding thermal stability. 14 Although the rigid polyimides exhibit poor tractability, hollow spheres can be prepared using the soluble precursor poly(amic acid)s. However, many of other aromatic polymers show neither fusibility nor solubility owing to their rigidity and it is too difficult to control the morphology precisely.

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Self-Organizing Polycondensation of (E)-4-Acetoxycinnamic Acid for Preparation of Poly(p-oxycinnamoyl) Microspheres

Cited by 35 publications

References 26 publications

Morphology Control of Aromatic Polymers in Concert with Polymerization

Morphology Control of Aromatic Polymers in Concert with Polymerization

Morphology Control of Poly(p-mercaptobenzoyl) by Modification of Oligomer End-group

Hollow spheres of aromatic polyamide prepared by reaction‐induced phase separation

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