M.C. Lagel^1,*, A. Pizzi^1,2, S. Giovando³

Journal of Renewable Materials, Vol.2, No.3, pp. 207-219, 2014, DOI:10.7569/JRM.2014.634111

Abstract Natural hydrolysable chestnut tannin extracts used to partially substitute phenol in Phenol-Formaldehyde (PF) resins for phenolic rigid foams were analysed by matrix-assisted desorption ionization time of fl ight (MALDI-TOF) mass spectrometry. PF only, chestnut only and PF-chestnut copolymerised oligomer types and distribution were determined. MALDI-TOF analyses of a PF control resin (with the same molar ratio) and of chestnut tannin extracts were performed in order to identify the peaks of molecular weights corresponding to copolymers of chestnut tannins with phenol and formaldehyde. More >

A. Sauget^1,*, X. Zhou¹, A. Pizzi^1,2

Journal of Renewable Materials, Vol.2, No.3, pp. 186-200, 2014, DOI:10.7569/JRM.2013.634138

Abstract Glyoxal and glutaraldehyde are two viable alternatives to formaldehyde for the preparation of tanninresorcinol-aldehyde adhesive but lead to less resistant glue joint. Tannin-resorcinol-glyoxal (TRG1) and tannin-resorcinol-glutaraldehyde (TRG2) resins have been prepared and analyzed by matrix-assisted laser desorption/ionization time of fl ight (MALDI-ToF) spectrometry to understand the chemical process behind the pre-curing of these resins and possibly the causes of this lower resistance. The analysis showed that TRG resins are not a simple mix of resorcinol-aldehydes oligomers and fl avonoids, but a much more complex combination of various species including tannin-aldehydes and tannin-resorcinol oligomers. More >

M.Thébault^*, A.Pizzi, E.Fredon

Journal of Renewable Materials, Vol.1, No.4, pp. 242-252, 2013, DOI:10.7569/JRM.2013.634121

Abstract Sunfl ower oil was subjected to a fl ow of compressed air containing ozone for different time periods. The addition of α-D-Glucose was used to increase the aldehyde content by reduction of the intermediate ozonides of the ozonation reaction. These new oils were analyzed by FTIR and GC-MS spectrometry, and their relative aldehyde groups content measured by the Henick method. They were then mixed with an aqueous solution of Radiata Pine tannin to form resins, subsequently analyzed by ¹³C NMR and MALDITOF mass spectrometry. Wood particleboards were then made using some of these resins as the More >

D.S. Liu^1,2, Z.H. Fong¹, I.H. Lin¹, Z.W. Zhuang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.6, pp. 441-468, 2013, DOI:10.3970/cmes.2013.093.441

Abstract In this study, we proposed a novel numerical technique to simulate the transient moisture diffusion process and to apply it to heterogeneous composite resins. The method is based on a heterogeneous hybrid moisture element (HHME), with properties determined through an equivalent hybrid moisture capacitance/ conductance matrix that was calculated using the conventional finite element formulation in space discretization and the q-method in time discretization, with similar mass/stiffness properties and matrix condensing operations. A coupled HHME with finite element scheme was developed and implemented in the computer code by using the commercial software MATLAB to analyze… More >

Kyousuke Yamaguchi¹, Nao-Aki Noda², Ker-Kong Chen³, Kiyoshi Tajima³, Seiji Harada¹, Xin Lan¹

Structural Durability & Health Monitoring, Vol.5, No.3, pp. 191-200, 2009, DOI:10.3970/sdhm.2009.005.191

Abstract Wedge-shaped defects are frequently observed on the cervical region of the human tooth. Previously, most studies explained that improper tooth-brushing causes such defects. However, recent clinical observation suggested that the repeated stress due to occlusal force may induce the formation of these wedge-shaped defects. In this study, a two-dimensional human tooth model after a wedge-shaped defect is restored with the composite resin is analyzed by using the finite element method. To obtain the intensity of the singular stress accurately, a method of analysis is discussed for calculating generalized stress intensity factors, which control the singular More >

Shishir Sinha¹, Vinay Kumar²

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.3, pp. 297-312, 2009, DOI:10.3970/fdmp.2009.005.297

Abstract High-capacity ion exchange resins based on Poly Methyl Methacrylate (PMMA) was developed during this study having higher mechanical strength, stable and, hydrophilic in nature compared to Poly styrene (PS) based systems. PMMA was cross-linked by Di Vinyl Benzene (DVB) to get macro porous PMMA-DVB resins by suspension polymerization. PMMA-DVB resins were surface modified by nitration followed by amination under appropriate temperature conditions. Change in the color of resin from white to pale yellow and pale yellow to golden yellow as well as characteristic peaks of NO2at 700 cm-1and 1400 cm-1and 3100-3200 cm-1for NH2group in FTIR More >