Entity

Time filter

Source Type

Fukui-shi, Japan

Hatakeyama T.,Lignocel Research Co. | Iijima M.,Nagasaki University | Hatakeyama H.,Fukui University of Technology
Food Hydrocolloids | Year: 2016

In terms of the functionalities of polysaccharides, water molecules play a crucial role. Two kinds of bound water, freezing bound water and non-freezing water have been classified based on the phase transition of water restrained by hydrophilic polymers. In this study, conversion of bound water accompanied with the structural change of two kinds of water insoluble polysaccharides, cellulose and curdlan, is investigated. It was found that bound water is involved in reversible and irreversible structural change of both cellulose and curdlan. Bound water contributes to the reversible structural change of natural cellulose, whose mechanical properties increase in the presence of water. In water-induced crystallization of amorphous cellulose, bound water is excluded from molecular chains and the crystalline region is irreversibly established. Transformation of freezing bound water to non-freezing water was observed when gelation mechanism of curdlan is changed from reversible to irreversible state. Quantification of bound water involved in the above process is described based on the melting enthalpy of ice restrained by cellulose and curdlan. © 2015 Elsevier Ltd. Source


Ismail T.N.M.T.,Malaysian Palm Oil Board | Hassan H.A.,Malaysian Palm Oil Board | Hirose S.,Japan National Institute of Advanced Industrial Science and Technology | Taguchi Y.,Japan National Institute of Advanced Industrial Science and Technology | And 2 more authors.
Polymer International | Year: 2010

Among various biomass-based components, both lignin and glycerol are important, since they are abundantly produced as by-products in industrial processes. Accordingly, in the present study, new types of crosslinked epoxy resins were synthesized from lignin and glycerol. Polymers derived from two types of lignin-based crosslinked epoxy resins were prepared through two-step reactions, ester-carboxylic acid derivative preparation followed by crosslinked epoxy resin preparation, in order to establish a crosslinked epoxy resin system in which glycerol units were included. The resins obtained were labeled as follows: series 1, lignosulfonate-glycerol polyacid (Ser1LSGLYPA); and series 2, glycerol diglycidyl ether (Ser2GLYDGE). The functional groups of the resins were analyzed using Fourier transform infrared spectrometry. The thermal properties of the resins were analyzed using differential scanning calorimetry and thermogravimetry. The glass transition temperature of the crosslinked epoxy resins increased with increasing LSGLYPA and GLYDGE contents for Ser1LSGLYPA and Ser2GLYDGE, respectively. The thermal degradation temperature for Ser1LSGLYPA and Ser2GLYDGE did not show significant change, suggesting that the crosslinked epoxy resins were thermally stable. The mass residue at 500 °C was not affected by the changes of LSGLYPA and GLYDGE contents. © 2009 Society of Chemical Industry. Source


Hatakeyama H.,Fukui University of Technology | Marusawa T.,Fukui University of Technology | Hatakeyama T.,Lignocel Research Co.
Journal of Materials Science | Year: 2011

Molasses (ML)-based soft-type polyurethane (PU) foams were successfully prepared by controlling evolved heat during chemical reaction. Two kinds of isocyanate, poly(phenylene methylene) polyisocyanate (MDI) and tolylene diisocyanate (TDI), and polypropylene glycol with a long molecular chain length were utilized to control the chemical reaction. The hydroxyl group in ML was used as the reaction site and soft-type PU foams were synthesized at isocyanate (NCO)/hydroxyl group (OH) ratios of 1.05. Mechanical properties of the above foams were controlled by changing the mixing ratio of MDI and TDI. Pore size and distribution were measured by scanning electron microscopy. With increasing thickness of cell wall, compression strength and modulus increased. Thermal properties of PU foams were investigated by differential scanning calorimetry, thermogravimetry, and thermal conductivity measurements. Two-step glass transition temperatures were observed at around ca. -55 and 80 °C, regardless of kind of isocyanate. The low temperature side glass transition is attributed to the molecular motion of long oxyethylene chains and the high temperature side transition is caused by rigid components including saccharide components. Thermal decomposition of PU foams started from ca. 270 °C. Thermal conductivity of soft-type PU was observed in a range from 0.034 to 0.035 J s-1 m-1 K-1. © Springer Science+Business Media, LLC 2011. Source


Hatakeyama H.,Fukui University of Technology | Hatakeyama H.,Lignocel Research Co. | Hatakeyama T.,Lignocel Research Co.
Journal of Renewable Materials | Year: 2013

Lignin and saccharides are two major components of plants. Huge amounts of plant residues are obtained as by-products of large-scale industries, such as pulp and paper, bio-fuel and the food industry. In this paper, preparation of polyurethane (PU) foam directly from various kinds of industrial lignin and molasses, which have scarcely been utilized, is summarized based on our results obtained by recent investigation. A onestep reaction using hydroxyl groups of plant materials as an active site makes it possible to produce a wide variety of PU, such as foams, sheets, gels and composite matrix. In this paper, PU foams receive particular focus. By controlling reaction conditions and the combination of plant components, mechanical and thermal properties can be varied in a wide range. Furthermore, industrial products using PU's derived from lignin and saccharides are competitive with those from petroleum in both functional properties and production price. © 2013 Scrivener Publishing LLC. Source


Hatakeyama H.,Fukui University of Technology | Hatakeyama H.,Lignocel Research Co. | Matsumura H.,Fukui University of Technology | Hatakeyama T.,Lignocel Research Co.
Journal of Thermal Analysis and Calorimetry | Year: 2013

Rigid polyurethane (PU) foams having saccharide and castor oil structures in the molecular chain were prepared by reaction between reactive alcoholic hydroxyl group and isocyanate. The apparent density of PU foams was in a range from 0.05 to 0.15 g cm-3. Thermal properties of the above polyurethane foams were studied by differential scanning calorimetry, thermogravimetry and thermal conductivity measurement. Glass transitions were observed in two steps. The low-temperature side glass transition was observed at around 220 K, regardless of castor oil content. This transition is attributed to the molecular motion of alkyl chain groups of castor oil. The high-temperature side glass transition observed in the temperature range from 350 to 390 K depends on the amount of molasses polyol content. The high-temperature side glass transition is attributed to the molecular motion of saccharides, such as sucrose, glucose, fructose as well as isocyanate phenyl rings, which act as rigid components. Thermal decomposition was observed in two steps at 570 and 620-670 K. Thermal conductivity was observed at around 0.032 J sec-1 m-1 K-1. Compression strength and modulus of PU foams were obtained by mechanical test. It was confirmed that the thermal and mechanical properties of PU foams could be controlled by changing the mixing ratio of castor oil and molasses for suitable practical applications. © 2012 Akadémiai Kiadó, Budapest, Hungary. Source

Discover hidden collaborations