Results on the effects of using nanoclay as filler in Urea Formaldehyde (UF) adhesive to finger-joint short pieces of Melia azedarach wood are reported in this paper. Three relatively low (0.5%, 1% and 1.5%) concentrations of nanoclay containing metallic oxides were used in the study. The results are indicative of the fact that all three concentrations were able to effectively enhance the bending strengths by 22% to 58% compared to sections joined using UF with no added nano-filler. A nanoclay concentration of 1% of UF resin powder weight resulted in the highest bending strength of 50.3 N/mm 2 . Comparing with the MoR of clearwood sections reported in literature, the efficiency could be enhanced from 51.7% up to a range of 63% to 81.8% by addition of nanoclay. The addition of nanoclay did not result in any significant changes in the MoE values of the finger jointed sections. The study demonstrates the value addition that can be brought to finger jointed sections of M. azedarach using nanoclay in low concentrations as filler in UF to enhance the bending strength of short pieces without compromising on the stiffness.

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Cette étude explore les effets de la délignification dans l’amélioration de quelques propriétés physiques du bois comprimé. Les billes de bois d’une plantation de six ans d’âge de Melia dubia (densité = 0,39 g/cm3) ont été délignifiées dans une solution alcaline de NaOH et Na2SO3 pendant 4 heures. Les billes de bois délignifiées ont été séchées jusqu’à contenir 12 % d’humidité, et comprimées à deux températures (120 °C et 150 °C) pendant 2 heures et 4 heures. Les améliorations dans la densité, la recouvrance de la compression (%) et la perte d’épaisseur (%) après la compression ont été observées et comparées avec des échantillons non délignifiés. La densité moyenne du bois délignifié et comprimé (DCW) était de 0,825 g/cm3 (SD = 0,109) ; pour le bois comprimé sans délignification (CW), la densité moyenne était de 0,889 g/cm3 (SD = 0,049). Ces densités diffèrent significativement : les échantillons de DCW ont montré une basse recouvrance de la compression (2,97 % à 5,22 %), tandis que, comparativement, les échantillons de bois CW ont montré une haute recouvrance de la compression (48,47 % à 38,05 %). La perte moyenne d’épaisseur (%) dans les échantillons de DCW a varié de 47,22 % à 52,26 %, et elle était approximativement de 10 % plus haute (58,77 % à 61,91 %) dans les échantillons de CW, sans délignification.

Background: Mould growth on coated wood products during shipment is the foremost apprehension for most of the wood industries in India. Well finished wood products tend to get deposited by staining moulds superficially in high humidity conditions during shipment. Though wood disfiguring fungi (stain moulds) normally have no significant effect on the mechanical properties of timber, they only affect the aesthetic appearance of the material without destructing the wood cell wall. This causes a huge economic loss to the manufacturer due to disfigurement of the appearance of wood products. Methods: The aim of this work is to test and enhance antimicrobial property of Nitrocellulose lacquer wood finish to prevent mould deposition on coated wood products. The work was carried out to screen and evaluate the antimicrobial activity of commercial Nitrocellulose lacquer. Several patents regarding antimicrobial activity of nano metal oxides have been visited. In order to enhance the mould resistance of this coating, its combinations with neem oil and ZnO nanoparticles were prepared and tested against the growth of staining moulds: Aspergillus niger and Penicillium sp. on the wood substrate of Melia dubia. The study was carried out for 500 hours under favorable conditions (Temperature and Relative Humidity (RH)) for the mould growth. The growth was analysed on the basis of surface area affected by stain moulds on coated wood samples. Results: The growth analysis data inferred that the ZnO nanoparticles had significant effect against the growth of stain moulds. The presence of ZnO nanoparticles increased the mould growth resistance of Nitrocellulose lacquer coating to a great extent compared to the ability of neem oil for the same. This finding demonstrates the potential use of nano ZnO for increasing the effectiveness of NC lacquer against mould growth without hampering its other properties. Conclusion: 1 % nano ZnO concentration in Nitrocellulose lacquer wood coating increased its efficacy against staining mould growth by 95 %.