synthesis and Properties of Thermotropic Liquid Crystalline Polyurethane Elastomers (II): Effect of Structure of Chain Extender Containing Imide Unit

Lee DJ; You SH; Kim HD

Korea Polymer Journal, Vol.7, No.6, 356-363, December, 1999

Lee DJ, You SH, Kim HD

We synthesized polyurethane elastomers containing imide unit for the first time. The polyurethane elastomers were prepared from poly(oxytetramethylene)glycol (PTMG) as a polyol of M_w 1000, 4,4''-diphenylmethane diisocyanate (MDI) as a diisocyanate, and chain extenders containing imide unit. The chain extenders are novel type of diols such as N,N-bis(6-hydroxyhexyl)-3,4,3'',4''-biphenyldicarboxyimide (BHHDI) and N,N''-bis[4-(6-hydroxyhexyloxy)phenyl]-3,4,3'',4''-biphenyldicarboxyimide (BHPDI). Both of the chain extenders have a flexible spacer of 6-methylene units and imide group, but a phenyl group between the flexible spacer and the imide moiety exists only in the dihydroxy compound BHPDI. The effects of the chemical structure of the chain extenders and hard segment content on the thermal and mechanical properties were studied. The thermal and mechanical properties of polyurethane elastomers were investigated by differential scanning calorimetry, dynamic mechanical thermal analysis, and tensilemeter. In the polyurethane elastomers (MHHs and MHP''s) the thermal stability, tensile strength, and initial modulus increase as the hard segment content is increased, whereas elongation at break reduces with increasing hard segment content. The chain extender BHPDI gives a polyurethane elastomer of higher thermal stability and mechanical properties than the chain extender BHHDI composed of imide unit and flexible spacer. This is attributed to different structural features of the chain extender.

[References]

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Kim HD, Lee TJ, Huh JH, Lee DJ, J. Appl. Polym. Sci., 73(3), 345 (1999)
Lee TJ, Lee DJ, Kim HD, J. Appl. Polym. Sci., to be submitted
Seymour RW, Cooper SL, Macromolecules, 6, 48 (1973)
Sung CSP, Schneider NS, Macromolecules, 8, 68 (1975)
Senich GA, MacKnight WJ, Macromolecules, 13, 106 (1980)
Lee DJ, Lee JB, Koide N, Akiyama E, Uryu T, Macromolecules, 31(4), 975 (1998)
Lamba NMK, Woodhouse KA, Cooper SL, Polyurethanes in Biomedical Applications, CRC, New York (1998)
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[1] Edwards KN, Urethane Chemistry and Applications, ACS, Washington, D.C., vol. 172 (1981)

[2] MacKnight WJ, Yang M, J. Polym. Sci. Polym. Symp., 42, 817 (1973)

[3] Koberstein JT, Gancarz I, Clark TC, J. Polym. Sci. B: Polym. Phys., 24, 2487 (1986)

[4] Brunette CM, Hsu SL, MacKnight WJ, Macromolecules, 15, 71 (1982)

[5] Christenson CP, Harthcock MA, Meadows MD, Spell HL, Howard WL, Crestwick MW, Guerra RE, Turner RB, J. Polym. Sci. B: Polym. Phys., 24, 1401 (1986)

[6] Coleman MM, Lee KH, Skrovanek DJ, Painter PC, Macromolecules, 19, 2149 (1986)

[7] Seymour RW, Estes GM, Cooper SL, Macromolecules, 3, 579 (1970)

[8] Estes GM, Cooper SL, Tobolsky AV, J. Macromol. Sci.-Rev. Macromol. Chem. Phys., C4, 167 (1970)

[9] Koutsky JA, Hien NV, Cooper SL, J. Polym. Sci. B: Polym. Phys., 8, 353 (1970)

[10] West JC, Cooper SL, J. Polym. Sci. Polym. Symp., 60, 127 (1977)

[11] Clough SB, Schneider NS, King AO, J. Macromol. Sci.-Phys., B2, 641 (1968)

[12] Zharkov VV, Strikovskii AG, Verteletskaya TE, Polym. Sci., 34, 142 (1992)

[13] Hepburn C, Polyurethane Elastomers, Elsevier Science, New York (1992)

[14] Kim HD, Lee TJ, Huh JH, Lee DJ, J. Appl. Polym. Sci., 73(3), 345 (1999)

[15] Lee TJ, Lee DJ, Kim HD, J. Appl. Polym. Sci., to be submitted

[16] Seymour RW, Cooper SL, Macromolecules, 6, 48 (1973)

[17] Sung CSP, Schneider NS, Macromolecules, 8, 68 (1975)

[18] Senich GA, MacKnight WJ, Macromolecules, 13, 106 (1980)

[19] Lee DJ, Lee JB, Koide N, Akiyama E, Uryu T, Macromolecules, 31(4), 975 (1998)

[20] Lamba NMK, Woodhouse KA, Cooper SL, Polyurethanes in Biomedical Applications, CRC, New York (1998)

[21] Bonart R, J. Macromol. Sci.-Phys., B2, 115 (1968)