African Journal of Wood Science and Forestry

African Journal of Wood Science and Forestry ISSN 2375-0979 Vol. 5 (3), pp. 288-295, May, 2017. © International Scholars Journals

Full Length Research Paper

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Categorization of exfoliated nano-composite of polyvinyl acetate and montmorillonite

*Tsung Qing Wen and lin Sun Yang

College of Wood Science and Technology, Nanjing Forestry University, Nanjing 210037, Jiangsu, China.

E-mail: [email protected]

Accepted 15 April, 2017

Abstract

To improve the chemical, physical, and mechanical properties of polyvinyl acetate (PVAc), montmorillonite (MMT) was added in the synthesis of PVAc in conventional lab conditions. The final product was studied mainly by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), static tensile, and the rheology was also investigated by the power-law function equation and the Cross-Williamson model viscous equation. The exfoliated nano-composite of PVAc-MMT was obtained. Linear macromolecular chains of PVAc were formed in MMT layers. MMT was exfoliated into layers or sheets of nano-particles, and randomly dispersed in PVAc matrix. The particle diameter of MMT ranged from 50 to 100 nm, while PVAc’s ranged from 250 to 500 nm, the smaller MMT particles were adsorbed around the larger PVAc particles to form the “Strawberry” structure. In addition, PVAc and PVAc-MMT were pseudo-plastic Non-Newtonian fluids, they all possessed the normal stress effect (or Weissenberg effect), that was the pole-climbing phenomenon.

Key words: Polyvinyl acetate (PVAc), montmorillonite (MMT), chemical structure, dispersion, particles, rheology, static tensile.

African Journal of Wood Science and Forestry ISSN 2375-0979 Vol. 5 (2), pp. 279-287, March, 2017. © International Scholars Journals

Full Length Research Paper

A study on the variation between provenances of Sclerocarya birrea sub-species caffra and seed mass of dried fresh seed

Oscar Jacobs Pienaar

Department of Forest and Wood Science, Faculty of Agrisciences, University of Stellenbosch, South Africa.

Email: [email protected]

Accepted 19 February, 2017

Abstract

Sclerocarya birrea (A. Rich.) Hochst. subsp. caffra (Sond.) Kokwaro (Marula) is one of the traditionally important indigenous multi-purpose fruits trees in Africa, which has been commercialized as its fruits and processed nuts/kennels have entered local, regional and international trade. This study was an analysis of the variation between and within provenances of S. birrea sub-species caffra with respect to seed mass of dried fresh seed, total soluble solids (total sugars) content of fresh fruits, and the vitamin C content of fresh fruits as well as family heritabilities of fruit parameters and seed mass. A nested sampling procedure was followed for where there were four areas (provenances), eight to ten families (parent trees) and fifty fruits per family. There were significant differences in provenance and family in seed mass (p=0.06 and p=0.0001) and vitamin C (p=0.001 and p=0.0001), total soluble solids lacked provenance variation (p=0.35) but had wide family variation (p=0.0001). There was no correlation between parameters except a significant correlation between rainfall intensity and total soluble solids content; lower the rainfall higher the sugar content and the higher the rainfall the lower the sugar content (p=0.06). The most variable parameter was vitamin C with the highest family heritability, however all traits had relatively high family heritabilities (above 0.5). It was concluded that the results of fruit composition and seed mass could be of remarkable importance in the identification of superior genotypes, making use of the wide family variation that exists. A study to capture a wider range of provenances and families including studying the environmental parameters of soils, rainfall and altitude for more precision.

Key words: Traits, parameters, correlation, variance.

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Utilization of wood off-cuts to maximize profit margins and to relieve pressure on existing species

Oscar Jacobs Pienaar

Department of Forest and Wood Science, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa.

E-mail: [email protected]

Accepted 10 January, 2017

Abstract

Indigenous hardwoods off-cuts generated by most mobile sawmillers are usually discarded resulting in under utilisation of timber and reduction of profit margins. The traditional indigenous species used in wood flooring have poor regeneration and slow growth thus cannot indefinitely sustain fast harvesting rates. Equipment required to assess the suitability of wood for specific applications is not readily available in Zimbabwe, so a simple abrasive-wear resistance test device was used as an alternative. The device can be constructed in any wood technology laboratory equipped with basic machine tools. Hardness and abrasive-wear resistance tests were performed on the radial and tangential faces of selected hardwoods to assess their performance in wood flooring. The results showed slightly higher hardness on the tangential face in poplar and mahogany only and that hardness increased with wood density. This study showed that neither the hardness value nor wood density can sufficiently explain increased abrasive-wear resistance because this is controlled by certain compounds found in wood cavities. However, ranking of selected hardwood species into different wood flooring traffic classes was similar for hardness values and abrasive-wear resistance indices. This illustrated the potential for using abrasive- wear resistance tests device as an alternative technique. Successful use of this device may assist in the identification of alternative species, relieve pressure on commercial indigenous species and facilitate collection of performance data and other wood species suitable for wood flooring. 

Key words: Hardness value, abrasion-wear resistance index, basic wood density, wood flooring.

African Journal of Wood Science and Forestry ISSN 2375-0979 Vol. 4 (8), pp. 254-273, August, 2016. © International Scholars Journals

Full Length Research Paper

Tissue dimensions and proportions of the stem and branch woods of Aningeria Robusta (A. Chev) and Terminalia Ivorensis (A. Chev)

Charles, Antwi-Boasiako¹ and Sitsofe, Apreko-Pilly²

Department of Wood Science and Technology, Faculty of Renewable Natural Resources, Kwame Nkrumah University of Science and Technology, Kumasi-Ghana.

Corresponding author. E-mail: [email protected]; +233(0)261663740

Received 20 April, 2016; Revised 03 June, 2016; Accepted 05 June, 2016 and Published 30 August, 2016

Abstract

To enhance wood economic value and effective utilization, knowledge of its properties, which impact its service behaviour, is indispensable. Fibre and vessel dimensions and tissue proportions of Aningeria robusta and Terminalia ivorensis stem wood and branch wood were compared. Stem wood recorded wider vessel lumen diameter, greater fibre and vessel proportions with less parenchyma than the branch wood. Fibre length, diameter, lumen diameter and double wall thickness were greater forT. ivorensis stem wood (1296.7-1508.6, 19.8-23.4, 13.3-17.3 and 6.0-6.5µm respectively) than branch wood (1046.0-1116.5, 19.2-21.2, 13.1-15.2 and 5.7-6.3µm respectively). Similarly, A. robusta stem wood recorded greater values (1182.9-1302.3, 22.9-23.9, 15.3-18.6 and 6.2-7.6µm respectively) than branch wood (995.1-1145.3, 20.1-22.42, 15.1-17 and 4.9-5.6µm respectively). Fibre proportions decreased up their stems (51.5-42.5%) and branches (51.2-40.0%). Their sapwood and heartwood vessel and parenchyma proportions were greater at bases than crowns. Vessel lumen diameters increased with stem height but decreased along branches. Consequently, their stem woods would have superior load-bearing capacity, be coarse-textured and produce great tear-resistant papers. Branch woods would have great density, be close-textured and suitable for product finishing and bulky paper production. Knowledge about branch wood properties would ensure proper understanding of their service performance and utilization. This would supplement their wood volumes and broadening the raw material base for the timber industry.

Key words: Axial stem position, anatomical feature, branch wood, fibre length, parenchyma cell, tissue proportion, vessel lumen diameter, fibre wall thickness, wood macerate.

African Journal of Wood Science and Forestry ISSN: 2375-0979 Vol. 4 (4), pp. 247-253, April, 2015. © International Scholars Journals

Full Length Research Paper

Contribution of a tropical fungus to premature failure of CCA treated Eucalyptus grandis poles in Kenya: Evidence of copper tolerance at Groundline attack

Sirmah Peter^1,3, Glassion Chelule², Hitimana Joseph¹ and Njue Naomi¹

¹School of Natural Resource and Environmental Management, University of Kabianga, P.O. BOX 2030-20200, Kericho, Kenya.

²Department of Forestry and Wood Science, University of Eldoret, P.O. BOX 1125-30100, Eldoret, Kenya.

*Correspondingauthor.Email:[email protected]

Accepted 3 April, 2015

Abstract

Studies were carried out to understand the contribution of fungi to premature failure of Copper Chrome Arsenate (CCA) treated Eucalyptus grandis poles used in Kenya for structural purposes. Wood chips from ground line contact in CCA treated E. grandis poles were cultured and re-cultured in laboratory under sterile conditions, 25°C and relative humidity of 75% for 10days. The fungus obtained was further cultured in 100, 500 and 1000ppm CCA in Potato Dextrose Agar (PDA) and growth inhibition evaluated. Fungal growth inhibition ranged from 38% to 82% at 100 to 1000ppm CCA respectively. Wood specimens treated with1000ppm CCA or not treated and exposed to the fungus in a standard laboratory soil bed gave weight losses of 8% and 28% respectively. It is concluded that the fungus was able to detoxify copper as evidenced by the formation of brown ring during initial stages of decay and growth. It is not only through copper detoxification and tolerance that the fungus is able to bring about premature wood failure. Soil pH, site factors and CCA leaching as reported in similar studies, work in a synergistic manner to accelerate the failure of CCA treated wood poles, explaining the huge losses experienced in Kenya.

Key words: CCA, tropical fungus, premature failure, Eucalyptus grandis.          

African Journal of Wood Science and Forestry ISSN: 2375-0979 Vol. 4 (3), pp. 238-246, March, 2016. © International Scholars Journals

Full Length Research Paper

Radial variation of anatomical properties in 8-year-old clones of Acacia hybrid (A. mangium x A. auriculaeformis)

S.K. Sharma*, S.R. Shukla and M. Sujatha

Wood Properties and Engineered Wood Division, Institute of Wood Science and Technology, P.O. Malleswaram, Bangalore-560 003, India.

Received 09 January, 2016; Accepted 21 February, 2016

*Corresponding author: E-mail: [email protected]. Tel. +91-80-22190170; Fax: +91-80-23340529

Abstract

The radial variation of anatomical properties in three clones (HD3, K47 and H4) of 8-year-old Acacia hybrid (Acacia mangium x Acacia auriculaeformis), grown by the Mysore Paper Mills, Bhadravati, Karnataka (India), is reported. The fibre and vessel morphology were studied from pith to periphery and variations between the clones were analyzed statistically. Various anatomical properties were also compared with the pure forms of A. mangium as well as A. auriculaeformis of identical age. Certain anatomical parameters such as fibre length, fibre diameter, fibre lumen diameter and vessel diameter showed significant radial variation from pith outwards. However, vessel frequency did not exhibit much radial variation. Fibre length was found to be positively correlated with vessel diameter, vessel element length and negatively correlated with fibre diameter and fibre lumen diameter. The correlation coefficients between various anatomical parameters were also computed and analyzed statistically. The results showed that inter clonal variation in various anatomical properties was significant except fibre lumen diameter and vessel diameter. All the clones showed longer fibres (1001-1078 µm) compared to pure forms of A. mangium (995 µm) and A. auriculaeformis (828 µm). Runkel ratio (0.644-0.679) and shape factor (0.443-0.471) values obtained in the present study are within the prescribed range to produce pulp of reasonable quality.

Key words: Acacia hybrid, A. mangium, A. auriculaeformis, clones, fibre and vessel morphology, Runkel ratio.