Abstract

The chemical composition of wood is an important factor affecting the properties and utilization of wood. To compare the difference in chemical compositions between heartwood and sapwood of red-heart Chinese fir (Cunninghamia lanceolata), three graded wood, dominant, average, and overtopped trees were selected from the Chenshan Forest Station of Anfu County in Jiangxi Province. Their chemical composition parameters were determined according to international standards. Our results indicate that sapwood contains on average a higher moisture content than that of heartwood, constituting 9.4 and 8.6 percent, respectively. The pH values of wood present acidic and are higher in sapwood. Cellulose is abundant in both wood tissues; the heartwood content (52.0%) is higher than that of sapwood (48.6%) on average. Furthermore, the lignin in heartwood is slightly less than that of sapwood. Hemicellulose content is similar in heartwood and sapwood (23.4% vs. 23.1%), on average. All kinds of extractives in heartwood are substantially richer. Approximately three times more benzene–ethanol extractives are in heartwood than sapwood. This suggests that there is a considerable variation of chemical constituents among the graded woods (P < 0.05). The pH values are both significantly correlated with the contents of the four extractives in heartwood and sapwood (P < 0.05). The longitudinal variation of chemical compositions is different along the direction of tree height in heartwood and sapwood. Understanding the chemical heterogeneity of wood is vital for wood product manufacturing as well as for wood property improvement.

Abstract

The ability to efficiently and consistently characterize the quality of hardwood sawlogs is an indispensable part of operating a hardwood sawmill. And it is equally important for buyers and sellers of hardwood logs to negotiate prices on a uniform basis of both scale and grade. While scaling of logs is relatively straightforward, assuming buyer and seller agree on a specific log rule to use (e.g., Doyle, Scriber, International), grading logs for the purposes of evaluating quality is more complex.

Hardwood log grading is an essential component of any hardwood sawmill's operation and effectively sets the stage for profit or loss. Various efforts have been made to develop a standardized log grading system by both the forest products industry and the US Department of Agriculture Forest Service (USDAFS) since the beginning of the 20th century. However, even after over a century of effort, there is still no broadly accepted standard for grading hardwood logs.

The purpose of this article is to document the historical evolution of hardwood log grading systems. Understanding the development of hardwood log grading systems over time can help to produce a better log grading standard in the future.

Abstract

The major effort to develop hardwood log grades was undertaken by the US Department of Agriculture Forest Service (USDAFS) during the 1940s through the 1960s. While the USDAFS officially adopted the grading system for their own use in 1952, it has never taken hold in the hardwood lumber industry. This article discusses the variety of reasons that have most likely contributed to this failure of adoption of the USDAFS system by the industry, ranging from ease of use, to individual log grades covering wide ranges of log characteristics/quality, and to overlapping grades for a given set of log attributes, among others. Finally, the authors suggest developing a hardwood log grading system that embraces the de facto industry system of scaling diameter and clear faces.

Abstract

This study aims to determine the impacts of dovetail angle for dovetail joints on the diagonal compression strength of box-type furniture corner joints prepared in different woods, with different dovetail angles, and with different adhesives. For this reason, after drilling joints of 75°, 78°, 81°, 84°, and 87° on Oriental beech, European oak, Scotch pine, and medium-density fiberboard (MDF) samples, a diagonal compression test was applied on corners glued with polyvinyl acetate (PVAc) and polyurethane (Desmodur-vinyl trieketonol acetate [D-VTKA]) according to the ASTM D1037 standard. The highest result for dovetail diagonal compression strength was observed in the samples of Oriental beech (0.321 N mm⁻²), while the lowest was found in the samples of MDF (0.154 N mm⁻²) for wood types. With respect to adhesives, D-VTKA yielded the best results (0.268 N mm⁻²), while PVAc gave the worst results (0.252 N mm⁻²). Regarding angle types, the best result was obtained from the samples at 84° (0.302 N mm⁻²) and the worst from the samples at 75° (0.207 N mm⁻²) for dovetail joints. For the interaction of wood type, adhesive, and dovetail angle, the highest diagonal compression strength was found in the samples of Oriental beech + 81° + D-VTKA (0.445 N mm⁻²), while the lowest value was observed in MDF + 78° + D-VTKA (0.128 N mm⁻²). In conclusion, the angles and adhesives have significant effects on the corner joints of box-type furniture.

Abstract

The addition of maleic anhydride (MA)-modified polypropylene (MAPP) as a compatibilizer increases mechanical and physical properties of wood/plastic composites (WPCs). It is thought that MA graft ratio (Gr), molecular weight (weight-average molecular weight [Mw]), and mixing methods of MAPP affect physical and mechanical properties of WPCs. However, evaluation, especially for mixing order, is not enough. The objective of this study was to investigate the effect of Gr and Mw of MAPP and its mixing methods on the mechanical and physical properties of WPCs. Two types of mixing methods were used: mixing the MAPP with the filler using a Henschel mixer before kneading with PP (premixing method) and mixing all of the materials at one time (one-step mixing method). The WPCs made with the premixing method had lower shear viscosity and higher flexural modulus than those made with the one-step mixing method. The particle size, moisture content, and surface morphology of fillers are thought to be more important in determining the shear viscosity of WPCs than the MAPP itself. The highest tensile, impact, and flexural strengths of WPCs were obtained in the WPC with premixing with low-Gr and high-Mw MAPP. It may be due to the effective reaction of the wood flour with MAPP and higher entanglement between the MAPP and PP. These results suggest that the premixing method could improve productivity and mechanical properties of WPCs.

Abstract

Ba(OH)₂ was added in the synthesis of phenol-formaldehyde resin to realize a low-temperature and fast-bonding process for plywood production. Plywood bonding was investigated by studying a number of parameters, such as the glue spread, the amount of curing agent, and the temperature and duration of the hot-pressing process. The plywood bonding strength was characterized by the shear strength of the adhesive layer, and a mathematical model describing the process and the response was developed using a central composite design and response surface methods. The variance analysis revealed that the newly developed model was reliable, with a high signal-to-noise ratio. All the factors and their interactions were analyzed to optimize the bonding process. Thus, seven optimized processes were obtained from the model, and the optimal process conditions were revealed (glue spread: 277.8 g/m²; amount of curing agent: 3.5%; hot-pressing temperature: 108°C; and hot-pressing duration: 34.99 s/mm). The results from repeated average shear strength experiments of five veneer testing samples (1.64 MPa) verified the reliability of the optimized technics.

Abstract

Methylene diphenyl diisocyanate (pMDI) adhesive used in the manufacture of oriented strand board and particleboard can be partially substituted with soy flour for significant cost savings. The flour is about one-third of the cost of pMDI. Properties such as internal bond, wet modulus of elasticity and modulus of rupture, and thickness swelling are unaffected by soy flour substitution of up to 20 percent. Adding soy flour to the regular dose of pMDI can improve board properties and reduce delamination.

Abstract

The online-to-offline (O2O) business mode, designed to attract online shoppers to participate in in-person retail consumption, is rapidly emerging in popularity in China, and having a significant impact on traditional manufacturing. Taking the wooden furniture industry as a case study, this research surveyed consumers' attitudes toward using the O2O mode for wooden furniture shopping. Respondents were asked to rate their online and in-store experiences and attitudes about wooden furniture shopping via the O2O mode. On the basis of data processing of questionnaires, this study established hypotheses and conducted hypothesis testing by one-way analysis of variance and regression analysis. Results of this research indicated that Chinese consumers' attitudes about using the O2O mode for wooden furniture shopping were significantly affected by the region/city tiers in which the respondents resided. Consumers' attitudes in all regions were affected by subjective perceptions, the reputation and security of the Internet platform, and the quality of enterprise services. Specifically, those who live in tier 1 cities (most economically developed cities, e.g., Beijing, Tianjin) are more concerned about their shopping environment, whereas those who live in tier 3 cities (less economically developed cities) are more concerned about the Internet platform's service and promotions. Tier 2 cities (large cities that may be provincial capitals) are more concerned about convenience of online shopping and environment of the offline store. The results of this study could help enable business managers to develop appropriate marketing strategies for O2O wooden furniture shopping and provide reference for the transformation of business mode of wooden furniture manufacturing enterprises.