Fukui-shi, Japan
Fukui-shi, Japan

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Hatakeyama T.,Lignocel Research | Tanaka M.,Tohoku University | Hatakeyama H.,Fukui University of Technology
Acta Biomaterialia | Year: 2010

The structural change of water restrained by poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) was investigated by differential scanning calorimetry (DSC), since the biocompatibility of PMPC and related biopolymers is affected by the structure of water on the polymer surface. The phase transition behaviour of PMPC-water systems with a water content (Wc = mass of water/mass of dry sample, gg1) in the range 0-2.0 was measured in the temperature range-150 to 50 °C. Glass transition, cold crystallization and melting were observed. Cold crystallization, which has been suggested as an index of biocompatibility, was detected for PMPC with a Wc in the range 0.5-0.9. The amounts of two types of bound water, non-freezing water and freezing bound water, were calculated from the melting enthalpy. The amount of non-freezing water of PMPC was ∼0.48. It was found that the phase transition behaviour and amount of bound water of PMPC were quite similar to those of water-soluble polysaccharide electrolytes. The results indicate that the bound water, not the free water, is restrained by PMPC. © 2010 Published by Elsevier Ltd. on behalf of Acta Materialia Inc. All rights reserved.

Hatakeyama H.,Fukui University of Technology | Tsujimoto Y.,Fukui University of Technology | Zarubin M.J.,Forestry Technical Academy | Krutov S.M.,Forestry Technical Academy | Hatakeyama T.,Lignocel Research
Journal of Thermal Analysis and Calorimetry | Year: 2010

Thermal properties of industrial hydrolysis lignin (HL) obtained from bio-ethanol production plants were investigated by thermogravimetry and differential scanning calorimetry. Thermal decomposition of HL was observed in two stages suggesting coexisting carbohydrates. Glass transition temperature (T g) was observed in a temperature range from 248 to 363 K. T g values were lower than that of other industrial lignins, such as kraft lignin or lignosulfate. Enthalpy relaxation was observed as sub-T g, which is not as prominent as other industrial or laboratory scale isolated lignins. T g of HL decreased in the presence of water and saturated at water content (W c) of 0.18 (mass of water/mass of dry HL). The amount of bound water calculated from melting enthalpy of water and W c was ca. 0.18. Thermal decomposition and molecular motion of as obtained industrial HL are affected by coexisting carbohydrates. © 2010 Akadémiai Kiadó, Budapest, Hungary.

Tay G.-S.,Fukui University of Technology | Tay G.-S.,Universiti Sains Malaysia | Nanbo T.,Fukui University of Technology | Hatakeyama H.,Fukui University of Technology | Hatakeyama T.,Lignocel Research
Thermochimica Acta | Year: 2011

Polyurethane composites filled with oil palm empty fruit bunches (EFB) were prepared using molasses and glycerol based polyols (MLP and GlyP). Glycerol is a by-product of biodiesel fuel (BDF) from palm oil, and EFB a residual component of the palm oil tree. MLP or GlyP was prepared by dissolving molasses or glycerol in polyethylene glycol. In the first series of composites, the NCO/OH ratio was varied from 0.1 to 0.5 at GlyP/MLP ratio of 50/50. In the second series of composites, the GlyP/MLP ratio was varied from 100/0 to 0/100 at NCO/OH = 0.4. Thermogravimetry (TG), dynamic mechanical analysis (DMA) and static mechanical tests of the above composites were carried out. It was found that thermal properties of the PU composites were markedly affected by the NCO/OH ratio and GlyP/MLP ratio. The thermal stability increased in the presence of molasses component in the polyol mixture. The segmental motion in PU composites was restricted by the presence of glycerol. Static mechanical tests indicated that the degree of cross-linking plays an important role in determining the efficiency of stress transfer from matrix to filler. © 2011 Elsevier B.V.

Hatakeyama T.,Lignocel Research | Inui Y.,Fukui University of Technology | Iijima M.,Nagasaki University | Hatakeyama H.,Lignocel Research | Hatakeyama H.,Fukui University of Technology
Journal of Thermal Analysis and Calorimetry | Year: 2013

The higher-order structure of natural cellulose fibres changes in the presence of water. In order to investigate the effect of molecular level fibre structure, melting behaviour of water restrained by nano- and microcellulose fibre was measured by differential scanning calorimetry. Fibre size was measured by scanning electron microscopy and atomic force microscopy. It was found that the melting peak of water restrained by microcellulose fibre started at 250-260 K in a W c (=mass of water/mass of dry sample) range from 0.5 to 1.2, whereas that of nanocellulose fibre was 230-237 K. Furthermore, peak temperature of melting of water restrained by nanocellulose was observed at around 270 K, in contrast, that of water restrained by microcellulose fibre was observed at ca. 275 K. Bound water content was calculated from melting enthalpy. Both non-freezing and freezing bound water of nanocellulose fibre was far larger than that of microcellulose. The above results suggest that a large amount of freezing bound water is restrained in nanocellulose fibres. It is thought that a larger number of isolated hydroxyl groups exist on the fibre surface. © 2012 Akadémiai Kiadó, Budapest, Hungary.

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

Sodium ligninosulfonate (LS)-based polyurethane (PU) foams were prepared using three kinds of ethylene glycols, diethylene glycol, triethylene glycol or polyethylene glycol. Two kinds of industrial NaLS, acid-based and alkaline-based NaLS, were mixed with various ratios, and foaming reactions were controlled. Mixing, cream, and rise time were used as an index of foaming reaction. Mixing time was defined as the time interval from adding isocyanate to detection of evolved heat under stirring, cream time as the time interval from termination of stirring to starting of foaming, and rise time as the time interval from starting to completion of foaming. The above reaction time increased with increasing amount of acid base NaLS content in polyols. Apparent density, compression strength and compression modulus of PU foams linearly increased with reaction time. Thermal decomposition temperature was measured by thermogravimetry and glass transition temperature by differential scanning calorimetry. Glass transition temperature can be controlled in a temperature range from 310 to 390 K by changing the mixing rate of two kinds of LS and molecular mass of ethylene glycols. It was found that mechanical and thermal properties of PU foams are controllable through the foaming reaction rate using two kinds of industrial lignin. © 2013 Akadémiai Kiadó, Budapest, Hungary.

Hatakeyama T.,Lignocel Research | Tanaka M.,Yamagata University | Kishi A.,Rigaku Co. Application Research Laboratory | Hatakeyama H.,Fukui University of Technology
Thermochimica Acta | Year: 2012

We attempted to compare the measurement methods concerning characterization of bound water restrained by hydrophilic polymers having biocompatibility, since the structural change of water on the surface of bio-membranes has attracted considerable attentions. In particular, calorimetry that has been used for quantitative analysis of bound water in bio-membranes has been criticised in terms of the results obtained by nuclear magnetic resonance spectrometry, infrared/Raman spectrometry, X-ray analysis, and neutron scattering measurements. Based on the identical definition of bound water, and by using biocompatible polymers, the present status of calorimetry is investigated in order to identify and quantify the bound water restrained by bio-membranes. © 2011 Elsevier B.V. All rights reserved.

Iijima M.,Nagasaki University | Takahashi M.,Shinshu University | Hatakeyama T.,Lignocel Research | Hatakeyama H.,Lignocel Research | Hatakeyama H.,Fukui University of Technology
Journal of Thermal Analysis and Calorimetry | Year: 2013

A broad temperature range of the gel-sol transition of κ-carrageenan was precisely examined by differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and the falling ball method (FBM). κ-Carrageenan the transition temperature of which ranged from 290 to 350 K was used as a representative sample of a thermo-reversible hydrogel. The starting of transition attributed to dissociation of the weak cross-linking zone of aggregated double helices was detected as a change of expansion coefficient by TMA and as an endothermic deviation by DSC. Peak temperature of endotherm by DSC agreed well with the temperature where expansion changed from positive to negative value and this temperature was attributed to gel-sol transition caused by dissociation of double helices' assembly. Transition temperature measured by FBM was observed at a temperature higher than those obtained by DSC and TMA, which was attributed to decomposition of double helices. © Akadémiai Kiadó, Budapest, Hungary 2013.

Einhorn-Stoll U.,TU Berlin | Hatakeyama H.,Fukui University of Technology | Hatakeyama T.,Lignocel Research
Food Hydrocolloids | Year: 2012

Water can be bound to food components and products as non-freezing, freezing-bound and free water. The interactions are crucial for any application as well as for food consumption and digestion. DSC was applied to examine the amounts of the different types of water bound to pectin, a biomacromolecule that is used as gelling and stabilising agent in many food products. One commercial high-methoxylated citrus pectin and three modified samples, prepared by acidic and alkaline demethoxylation as well as amidation, were tested. The water content of dry samples depended mainly on the molecular parameters, especially the content of hydrophilic groups at the galacturonic acid that was increased by demethoxylation and amidation, as well as on monovalent cations of the pectins. The water-pectin interactions of wetted materials were additionally influenced strongly by the availability of hydrophilic groups that depended on material properties such as amorphous or crystalline state, powder bulk and solid density and porosity as well as particle size, surface and porosity. Small amorphous porous particles, whose polar groups were rapidly available without prior softening and swelling, accelerated water uptake. Non-freezing and freezing-bound water, bound closely to the pectin molecules, depended on the number and type of polar groups. Free water, bound in micro- and macro-capillaries as well as voids within and between the pectin particles, was influenced by hydrophilic as well as hydrophobic groups of the samples. There was a strong impact of the pre-treatment during processing and modification. © 2011 Elsevier Ltd.

Hatakeyama H.,Fukui University of Technology | Hatakeyama T.,Lignocel Research
Advances in Polymer Science | Year: 2010

Polymeric features of lignin and its potential as a bio-resource are reviewed, focusing on its characteristic structure and properties. Lignin is a random copolymer consisting of phenylpropane units having characteristic side chains. Lignin slightly crosslinks and takes an amorphous structure in the solid state. The molecular motion is observed as glass transition by thermal, viscoelastic and spectroscopic measurements. The hydroxyl group of lignin plays a crucial role in interaction with water. By chemical and thermal decomposition, a wide range of chemicals can be obtained from lignin that can be used as starting materials for synthetic polymers, such as polyesters, polyethers, and polystyrene derivatives. At the same time, a variety of polymers can be derived from lignin by simple chemical modification. The hydroxyl group acts as a reaction site for the above chemical reaction. © Springer-Verlag Berlin Heidelberg 2009.

Hatakeyama T.,Lignocel Research | Tanaka M.,Yamagata University | Hatakeyama H.,Fukui University of Technology
Journal of Biomaterials Science, Polymer Edition | Year: 2010

This review focuses on the thermal properties of bound water restrained by various kinds of polysaccharides and several synthetic polymers. The characteristic features of freezing bound water which is closely related with biocompatibility of polymers are summarized based on results obtained by differential scanning calorimetry. Glass transition, cold crystallization and melting of water-polysaccharide systems were observed. Three kinds of water, non-freezing, freezing bound and free water, were quantified from the enthalpy of melting of water in the system. Freezing bound water restrained by polysaccharides is in a metastable state. The equilibrium melting temperature of freezing bound water is lower than 0°C and the temperature decreases with decreasing water content. Nucleation and growth rate of freezing bound water were calculated from isothermal crystallization and the values were compared with those of free water. © 2010 Koninklijke Brill NV, Leiden.

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