Ken Kojio

A series of eight aliphatic polycarbonate (PC) glycols with various methylene numbers (HO−[(CH2)mOC(═O)O]n−(CH2)m−OH, m = 3, 4, 5, 6, 7, 8, 9, and 10) were employed as a soft segment for a synthesis of polyurethane elastomers (PUEs). First of all, viscosity, glass transition temperature, melting point, and crystalline structure of these new PC-glycols were investigated. The PC-glycol-based PUEs were synthesized using the PC-glycols, 4,4′-diphenylmethane diisocyanate, and 1,4-butanediol by a one-

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

A novel diisocyanate, 1,2-bis(isocyanate)ethoxyethane (TEGDI), whose backbone is ether bonds was used for the preparation of polyurethane elastomers (PUEs). 1,6-Hexamethylene diisocyanate (HDI) was also used as a control. The PUEs were prepared with either TEGDI or HDI, poly(oxytetramethylene) glycol (PTMG), and curing agent by a prepolymer method. Differential scanning calorimetry, infrared spectroscopy, and wide-angle X-ray diffraction revealed that the phase separation of the network TEGDI-ba

Molecular arrangement of polymerized n-octadecyltrichlorosilane (OTS, CH3(CH2)17SiCl3) monolayer transferred onto hydrophilic substrate by an upward drawing method was investigated with a transmission electron microscope (TEM) and an atomic force microscope (AFM). The electron diffraction (ED) pattern of the OTS monolayer revealed that the OTS molecules were regularly arranged in a hexagonal array with a (10) spacing of ca. 0.42 nm. The high-resolution AFM image of the OTS monolayer in a scan ar

Abstract Randomly copolymerized poly(carbonate) glycols were employed as starting materials for the synthesis of polyurethane elastomers (PUEs). The poly(carbonate) glycols had hexamethylene (C 6 ) and tetramethylene (C 4 ) units between carbonate groups in various composition ratios (C 4 /C 6 = 0/100, 50/50, 70/30, and 90/10), and the number‐average molecular weights of these poly(carbonate) glycols were 1000 and 2000. The PUEs were synthesized with these poly(carbonate) glycols, 4,4′‐diphenylm

A comparative study in molecular arrangements of the n-octadecyltrichlorosilane (OTS) monolayer prepared by the Langmuir method and the chemisorption methods were carried out on the basis of grazing incidence X-ray diffraction (GIXD) and X-ray reflectivity (XR) measurements. The OTS molecules in the Langmuir OTS monolayer uniformly tilt ca. 8−10° to the surface normal and packed in a hexagonal lattice with the (10) spacing of 0.412 nm. On the other hand, the OTS molecules in the chemisorbed OTS

Abstract The effect of side methyl and dimethyl groups of the soft segment component on the microphase‐separated structure and mechanical properties of polyurethane elastomers (PUEs) was investigated. Poly(oxytetramethylene) glycol (PTMG), and PTMG incorporating dimethyl groups (PTG‐X) and methyl side groups (PTG‐L) were used as a polymer glycol, which forms a soft segment in the PUEs. The PUEs were synthesized with 4,4′‐dipheylmethane diisocyanate [1,1′‐methylenebis(4‐isocyanatobenzene)], 1,4‐b

Organoclay, such as organo-modified montmorillonite (MMT), is one of the potential filler candidates in the preparation of epoxy nanocomposite adhesives for automotive and civil engineering industries. However, there is no systematic research on the effect of organoclay reinforcement on its adhesion and fatigue behaviors in shear loading. Here, single-lap joints (SLJs) of stainless steel substrates bonded with epoxy/MMT nanocomposite adhesives, consisting of diglycidyl ether of bisphenol A and p

The deformation behavior of polythiourethane (PTU) elastomers was investigated using in situ small-angle X-ray scattering (SAXS), wide-angle X-ray diffraction (WAXD), and X-ray absorption fine structure (XAFS) methods. Two PTUs were prepared from poly(oxytetramethylene) glycol, 1,4-bis(isocyanatomethyl) cyclohexane, and 1,4-butanedithiol (PTU-B) or 1,5-pentanedithiol (PTU-P). The effect of methylene length of the chain extender on molecular aggregation structure of PTU during the elongation proc