Microphase-separated Structure of Ultrathin Polyurethane Films

We firstly observed the effect of film thickness on a microphase-separated structure of polyurethane at the ultrathin states. The interdomain spacing of domains decreased with decreasing film thickness due simply to the reduction of the space for domains.Nagasaki Symposium on Nano-Dynamics 2008 (NSND2008) 平成20年1月29日(火)於長崎大学 Invited Lectur

Synthesis and properties of highly hydrophilic polyurethane based on diisocyanate with ether group

Highly hydrophilic polyurethane elastomers (PUEs) were synthesized from 1,2-bis(isocyanate) ethoxyethane (TEGDI), poly(ethylene oxide-co-propylene oxide) copolyol (EOPO) and 1,4-butane diol/1,1,1-trimethylol propane (75/25) (wt/wt) by a prepolymer method. 4,4′-Diphenylmethane diisocyanate (MDI)-based PUEs were synthesized as a control as well. Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) measurements revealed that the degree of microphase separation of the TEGDI-based PUEs was much weaker than for the MDI-based PUEs. Young\u27s modulus and elongation at break of the TEGDI-based PUEs were quite lower and larger than for the MDI-based PUEs, respectively. This is due to quite weak cohesion force of the hard segment chains in the TEGDI-based PUEs. The degree of swelling of the TEGDI-based PUEs was five times larger than for the MDI-based one. This is associated with the hydrophilic nature of TEGDI and weak cohesion force in the TEGDI-based PUEs

Direct Observation of Microphase-separated Structure of Polyurethane by Temperature Dependent Atomic Force Microscopy

Nagasaki Symposium on Nano-Dynamics 2008 (NSND2008) 平成20年1月29日(火)於長崎大学 Poster Presentatio

Synthesis and Characterization of Rotaxane Closslinked Polyurethanes

Three polyurethanes (PU0, PU11 and PU33) where azobis(dibenzo-24-crown-8 ether) 1 acts as a crosslink point with a [3]rotaxane structure except PU0 were synthesized and characterized by H^^1 NMR and ATR-FT-IR spectroscopies, and DSC.Nagasaki Symposium on Nano-Dynamics 2008 (NSND2008) 平成20年1月29日(火)於長崎大学 Poster Presentatio

Chain and mirophase-separated structures of ultrathin polyurethane films

Measurements are presented how chain and microphase-separated structures of ultrathin polyurethane (PU) films are controlled by the thickness. The film thickness is varied by a solution concentration for spin coating. The systems are PUs prepared from commercial raw materials. Fourier-transform infrared spectroscopic measurement revealed that the degree of hydrogen bonding among hard segment chains decreased and increased with decreasing film thickness for strong and weak microphase separation systems, respectively. The microphase-separated structure, which is formed from hard segment domains and a surrounding soft segment matrix, were observed by atomic force microscopy. The size of hard segment domains decreased with decreasing film thickness, and possibility of specific orientation of the hard segment chains was exhibited for both systems. These results are due to decreasing space for the formation of the microphase-separated structure.IUMRS-ICA 2008 Symposium Sessions X and Y. Soft Matter Science, 9-13 December, Nagoya, Japa

Molecular Mobility of Soft Segment of Polyurethane Elastomers under Elongation

Abstract. In this study, we investigated molecular mobility of a soft segment in the poly(oxypropylene) glycol (PPG), 4,4\u27-diphenylmethane diisocyanate (MDI) and 1,4-butane diol (BD)-based polyurethane elastomers (PUE) with and without elongation by dynamic viscoelastic property measurement and pulse nuclear magnetic resonance (NMR) measurement. The peak position of the loss tangent (tand) curves shifted to the lower temperature region with increasing elongation. In the pulse NMR measurement, the long spin-spin relaxation time {T2) component appeared at -18.0 (e = 0) and -26.0 °C (e =1.5), respectively, with increasing temperature. Since this temperature seems to be related to the glass transition temperature (Jg) of the soft segment in the PUE, it is likely to consider that the Tg decreased with increasing strain. These results might be attributed that the size of cooperative motion during the glass transition decrease due to the orientation of the soft segment, and the soft segment phase approach to a pure phase on account of the extraction of the hard segment from the soft segment phase.THE XV INTERNATIONAL CONGRESS ON RHEOLOGY: The Society of Rheology 80th Annual Meeting : Monterey (California), 3?8 August 200

Porous In2O3 powders prepared by ultrasonic-spray pyrolysis as a NO2-sensing material: Utilization of polymethylmethacrylate microspheres synthesized by ultrasonic-assisted emulsion polymerization as a template

NO2-sensing properties of porous In2O3 (pr-In2O3) powders prepared by ultrasonic-spray pyrolysis employing polymethylmethacrylate (PMMA) microspheres as a template has been investigated in this study. The PMMA microspheres were synthesized in water by ultrasonic-assisted emulsion polymerization employing methyl methacrylate monomer, sodium lauryl sulfate as a surfactant and ammonium persulfate as an initiator. The PMMA microspheres synthesized was quite uniform and the particle size was ca. 60.2 nm (measured by dynamic light scattering). The microstructure of pr-In2O3 powders prepared was largely dependent on the kind of In2O3 sources. The pr-In2O3 which was prepared from In(NO3)3 as an In 2O3 source (pr-In2O3(N)) consisted of submicron-sized spherical particles with welldeveloped spherical mesopores (several tens of nanometers in pore diameter) and each oxide wall among pores was constructed with meso-sized In2O3 particles connected continuously. On the other hand, the pr-In2O3 which was prepared from InCl3 as an In2O3 source (pr-In2 O3(Cl)) was composed of a large number of dispersed meso-sized particles and a few submicron-sized dense spherical particles. In contrast, the morphology of conventional In2O3 powder (c-In 2O3) prepared by ultrasonic-spray pyrolysis of PMMAfree In(NO3)3 aqueous solution as a reference was relatively dense and roughly spherical with a diameter of ca. 100-700 nm. The responses to 1.0 and 10ppm NO2 of pr-In2O3 sensors in air were much larger than those of a c-In2O3(N) sensor in the temperature range of less than 250°C and 300°C, respectively. In addition, the response and recovery speeds of both the pr-In2O 3 sensors were much faster than those of the c-In2O 3(N) sensor, because of the well-developed porous structure of the pr-In2O3 sensors

Control of Mechanical Properties of Thermoplastic Polyurethane Elastomers by Restriction of Crystallization of Soft Segment

Mechanical properties of thermoplastic polyurethane elastomers based on either polyether or polycarbonate (PC)-glycols, 4,4’-dipheylmethane diisocyanate (1,1’-methylenebis(4-isocyanatobenzene)), 1,4-butanediol, were controlled by restriction of crystallization of polymer glycols. For the polyether glycol based-polyurethane elastomers (PUEs), poly(oxytetramethylene) glycol (PTMG), and PTMG incorporating dimethyl groups (PTG-X) and methyl side groups (PTG-L) were employed as a polymer glycol. For the PC-glycol, the randomly copolymerized PC-glycols with hexamethylene (C6) and tetramethylene (C4) units between carbonate groups with various composition ratios (C4/C6 = 0/100, 50/50, 70/30 and 90/10) were employed. The degree of microphase separation and mechanical properties of both the PUEs were investigated using differential scanning calorimetry, dynamic viscoelastic property measurements and tensile testing. Mechanical properties could be controlled by changing the molar ratio of two different monomer components