Mutsuhisa Furukawa

Controlling of Higher Order Structure and Friction/Abrasion of Polyurethane by Surface Modification Part, 3. Surface Modification by IPN of Polyurethane Elastomers with Florin-Containing Polymethacrylate.

Surface layer of Polyurethanene elastomers (PUEs) was modified by the use of 1H, 1H, 5H-Octafluoropentyl-methacrylate(OFPMA). The based PUE was prepared from poly(oxytetramethylene)glycol (PTMG, Mn=2037), 4, 4-diphenyl methane diisocyanate(MDI), and 1, 4-butanediol(BD)/ trimethylolpropane (TMP). OFPMA and ethylene glycol dimethacrylate (EGDMA) were penetrated into the surface layer of PUE and polymerized. Morphology, friction and abrasion characterization of the modified PUEs were studied by means of FT-IR, polarizing microscope, SEM, contact angle tester, Heidon 14 friction tester and DIN abrasion tester. The modified PUEs exhibited lower friction coefficient and better abrasion resistance compared with the unmodified PUE. The mechanism of the improvement was discussed.

Synthesis of degradable polyurethane incorporated with oligolactide compoment.

Lactide oligomer with molecular weight of 460 was synthesized and reacted with poly (oxytetramethylene) glycol (PTMG; Mn=650) to obtain oligolactide-terminated PTMG. Polyurethane was synthesized by the oligolactide-terminated PTMG, 4, 4′-diphenylmethane diisocyanate, and 1, 4-butanediol. The mechanical and thermal properties of the polyurethane was studied and compared with PTMG based polyurethane. The degradation behavior of the polyurethane put in the compost was evaluated by SEM, mechanical properties, and weight loss. The surface of the polyurethane degraded for 6 weeks had considerable number of voids. Modulus and weight significantly decreased with increasing time. On the other hand, control PTMG-based polyurethane showed no change after 6 weeks. These results indicate that the novel polyurethane having oligolactide moiety in the backbone-chain easily degrade under bio-active conditions.

Surface modification of polyurethane elastomers interpenetrated by polymethacryloylisocyanate.

Surface layer of polyurethane elastomers (PUEs) was modified by the use of methacryloylisocyanate (MAT). PUEs were prepared from poly (oxytetramethylene) glycol (Mn=2000), MDI and BD/TMP. MAT was penetrated into the surface layer of PUEs and polymerized. Morphology, dynamic mechanical properties, friction and abrasion chracteristics of these modified PUEs were studied by means FT-IR, polarizing microscope, dynamic viscoelastometer, Heidon 14 friction tester and DIN abraser. The modified surface layer was constituted of interpenetrating polymer network due to polymerization of MAI. The modified PUEs exhibited lower friction coefficient and higher abrasion compared with the unmodified PUE. The PUEs containing 5 to 8 per cent PMAI by weight showed the lowest friction coefficient and excellent abrasion resistance.

EFEFCTS OF SOFT SEGMENTS ON THERMAL DECOMPOSITION OF POLYURETHANE ELASTOMERS

Effect of soft segment structure on mechanisms of thermal decomposition of polyurethane elastomers was studied by means of pyrolysis high-resolution gas chromatography, equipped with a double shot capillary column. Polyurethane (PUs) used were prepared from poly (oxypropylene) glycol, poly (butylene adipate) glycol, poly (β-methyl-γ-valerolactone) glycol, or hydroxy-terminated polybutadiene, 2, 4-tolylene diisocyanate and 1, 4-butanediol. PUs were decomposed at 450, 500, 550, 600 and 650°C. Temperature dependence of the relative peak intensity of TDI in the pyrograms was led to following results; thermal dissociation reaction of urethane groups increases with the increase of decomposition temperature. PPG-PUs and Polyester PUs decompose mainly by thermal dissociation and decarboxylation, respectively. HTPB PUs decompose by both mechanisms.