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103 results on '"Kajiyama, Mikio"'

45. Synthesis and Properties of Block Copolymers Based on Carboxyl-Terminated Polydimethylsiloxane and Aromatic Polyamides

Author

Kakimoto, Masa-aki, Kajiyama, Mikio, and Imai, Yoshio

Abstract

Polysiloxane-aramid block copolymers were synthesized by a one-pot two-step method of direct polycondensation using triphenyl phosphite and pyridine as the condensing agents. Amine-terminated aramid oligomers were prepared by the reaction of 3,4'-oxydianiline and isophthalic acid, and subjected to polycondensation with a,?-bis(10-carboxydecyl) olydimethylsiloxane to give block copolymers with inherent viscosities of 0.13—0.25 di g-1. They were soluble in amide-type solvents like N,N-dimethylacetamide and gave translucent and ductile films by casting from the solutions. These block copolymers start to decompose around 300°C. These properties are very similar to those of block copolymers derived from a,?-bis(3-aminopropyl)polydimethylsiloxanes and carboxyl-terminated aramid oligomers.

Published
1986
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46. Synthesis and Properties of Block Copolymers Based on Amine-Terminated Polydimethylsiloxane and Aromatic Polyamides

Author

Kajiyama, Mikio, Nishikata, Yasunari, Kakimoto, Masa-aki, and Imai, Yoshio

Abstract

Polysiloxane-aramid block copolymers were synthesized by a one-pot two-step method of direct polycondensation using triphenyl phosphite and pyridine as the condensing agent. Carboxyl-terminated aramid oligomers were prepared by the reaction of 3,4'-oxydianiline and isophthalic acid, and then condensed with bis(3-aminopropyl) olydimethylsiloxane giving the block copolymers with inherent viscosities of 0.21—0.41 d1 g-1. They are soluble in amide-type solvents like N,N-dimethylacetamide and gave translucent and ductile films by casting from the solutions. These block copolymers start to decompose around 300°C.

Published
1986
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47. Improved Synthesis of Polyether-Aramid Multi-Block Copolymers by Direct Polycondensation

Author

Imai, Yoshio, Kajiyama, Mikio, Ogata, Shin-ichi, and Kakimoto, Masa-aki

Abstract

Polyether-aramid multi-block copolymers having structural regularity were synthesized by a one-pot two-step method of direct polycondensation using triphenyl phosphite and pyridine as condensing agents. Amine-terminated telechelic aramid oligomers were prepared by the reaction of bis(4-aminophenyl) ether and isophthalic acid, and subsequently condensed with a,?-poly(oxyethylene)dicarboxylic acid giving the multi-block copolymers with inherent viscosities of 0.5—0.7 dl g-1. No appreciable differences in thermal and tensile properties were observed between the multi-block copolymers thus prepared and those synthesized by the previously reported two-pot method. In contrast, the properties of these block copolymers differed significantly from those of a randomly coupled block copolymers prepared by the one-step procedure.

Published
1985
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49. Synthesis and Properties of Multi-Block Copolymers Based on Poly(oxyethylene)s and Aromatic Polyamides

Author

Imai, Yoshio, Kajiyama, Mikio, Ogata, Shin-ichi, and Kakimoto, Masa-aki

Abstract

Polyether–aramid multi-block copolymers having high structural regularity were synthesized by the direct polycondensation of poly(oxyethylene)dicarboxylic acids with amine-terminated telechelic aromatic polyamide (aramid) oligomers using triphenyl phosphite and pyridine as the condensing agent. The polymerizations at a total oligomer concentration of 100—200 gl-1in a mixture of pyridine and N-methyl-2-pyrrolidone afforded the block copolymers having inherent viscosities of 0.4—0.9 dlg-1. These multi-block copolymers are soluble in N,N-dimethylacetamide (DMAc) and gave transparent, ductile, and elastomeric films by casting from DMAc solutions. Moisture regain of these films is 5—6% in 60% relative humidity at 25°C. On the DTA curves in nitrogen, these copolymers exhibited two strong exothermic peaks at around 270 and 410°C; the former temperature corresponds well to the initial weight loss temperature on the TG curves. In the polyether–aramid multi-block copolymers, tensile strength and modulus of the films fall with an increase in the poly(oxyethylene) content, whereas elongation at break increases.

Published
1984
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