Effects of Resin Content on the Characteristics of Bamboo Oriented Strand Board Prepared from Strands of Betung, Ampel, and Their Mixtures

The objectives of this research were to evaluate bamboo-oriented strand board (BOSB) characteristics made from betung (Dendrocalamus asper), ampel (Bambusa vulgaris), and their mixtures at two different contents (3% and 5%) of methylene diphenyl di-isocyanate (MDI) adhesives. The strands were steam-treated at 126°C for 1 h under the pressure of 0.14 MPa. Three-layered BOSBs with a target density of 0.7 g/cm3 were made with the size of 30 cm x 30 cm x 0.9 cm and a shelling ratio of 1:2:1 (face:core:back layers). The physical and mechanical properties of BOSB were evaluated following JIS A 5908 (2003) standard, and the results were compared with the CSA 0437.0 Grade O-1 standard. The results show that BOSB from the mixtures of betung and ampel bamboo strands has higher dimensional stability as shown by the decrease in water absorption and thickness swelling and higher mechanical properties than single BOSB. All BOSBs with 5% resin content have higher dimensional stability, MOE, and MOR than BOSB with 3% resin content. The physical and mechanical properties of all BOSB manufactured met the CSA 0437.0 Grade O-1 standard. This study proved that BOSBs from the mixture of betung and ampel strands have the potential to be developed due to having better physical and mechanical qualities than a single BOSB. Keywords: ampel (Bambusa vulgaris), bamboo oriented strand board, betung (Dendrocalamus asper), resin content, strand mixtures

Feasibility of using low resin content levels in the production of bamboo particle composite: basic properties

In this study, the suitability of Semantan bamboo (Gigantochloa scortechinii) particles in the production of single-layered composite board was investigated. The effects of different resin types and lower resin content levels on the basic properties (mechanical and physical properties) of particle composite board made from G. scortechinii were determined. The 12-mm thickness boards with dimension of 340 × 340 mm and targeted density of 660 kg/m3 were fabricated. Types of resin used were melamine urea formaldehyde (MUF) and urea formaldehyde (UF), while resin content levels were 3.5 and 5%. In general, the mechanical and physical properties of board blended with MUF resin were better than UF due to the presence of melamine in MUF that influenced the properties. Board made from 5% resin content were better in term of mechanical and physical properties than 3.5% resin content levels. 5% resin content level had increased the particles bonding ability, thus influenced the excellent properties of the board. However, in general, the properties of bamboo particle composite board in this study were not comparable to the board made from wood. Only IB properties of bamboo particle composite board exceeded the minimum requirements as stipulated in standards. As a consequence, the information of particle composite board made from bamboo is important in assessing bamboo’s usefulness as an alternative raw material for wood-based industries. The final results obtained could be used as reference for researchers and manufacturers.

Outdoor Wood Mats-Based Engineering Composite: Influence of Process Parameters on Decay Resistance against Wood-Degrading Fungi Trametes versicolor and Gloeophyllum trabeum

The process parameters significantly influence the preparation and final properties of outdoor wood mats-based engineering composite (OWMEC). During outdoor use, wood composites are susceptible to destruction by rot fungi. Herein, the role of process parameters such as density and resin content on OWMEC resistance to fungal decay was investigated. The poplar OWMEC samples were exposed to white-rot fungus Trametes versicolor and brown-rot fungus Gloeophyllum trabeum for a period of 12 weeks. The chemical composition, crystallinity, and morphology were evaluated to investigate the effect of process parameters on the chemical composition and microstructure of the decayed OWMEC. With an increase in the density and resin content, the mass loss of the decayed OWMEC decreased. The highest antifungal effect against T. versicolor (12.34% mass loss) and G. trabeum (19.43% mass loss) were observed at a density of 1.15 g/m3 and resin content of 13%. As results of the chemical composition and microstructure measurements, the resistance of OWMEC against T. versicolor and G. trabeum fungi was improved remarkably by increasing the density and resin content. The results of this study will provide a technical basis to improve the decay resistance of OWMEC in outdoor environments.

Size Effect of Core Strands on the Major Physical and Mechanical Properties of Oriented Strand Boards from Fast Growing Tropical Species

Oriented strand board (OSB) is generally used for sheathing in residential walls, floors, and roofs. Because of its low pricing and utilisation of tiny diameter logs from fast-growing trees and thinning logs as raw materials, OSB is anticipated to gain popularity. In chapter, board properties of OSB using smaller strand size of Leucaena leucocephala as core layer had been studied. Small strand size of S3 (length = 75 mm, width = 3.2 to 6.3 mm) was located in the middle layer of the board while bigger strand sizes of S1 (length = 75 mm, width = 12.7 to 19.0 mm) and S2 (length = 75 mm, width = 6.3 to 12.7 mm) were located at the face and back layers. Utilization of smaller strands (S3) in the middle layers may yield boards that have better physical and mechanical properties. Except for MOR in the minor axis, board density and resin content were shown to have a substantial impact on physical and mechanical properties. Except for MOR in the major axis, strand size had little affected on physical and mechanical properties. The effects of board density on mechanical properties were discovered to affect significantly different. With a positive correlation, board density had a significant effect on thickness swelling. Between S1+S3 and S2+S3 strand size, there is no significant effect on bending properties, internal bond strength and thickness swelling. The effect of resin content on bending properties revealed a significant difference of MOR in major axis, as well as MOE values in both major and minor axes. Even when the resin content was as low as 5%, all treatments of OSB passed the general requirement of general purpose OSB.

Preparation of ZnO Nanoparticle/Acrylic Resin Superhydrophobic Coating via Blending Method and Its Wear Resistance and Antibacterial Properties

Herein, a facile method for the preparation of an acrylic resin-based superhydrophobic coating is provided. Firstly, ZnO nanoparticles were modified with silane to obtain hydrophobic ZnO, which was then homogeneously blended with acrylic resin. Subsequently, the mixture was sprayed on an aluminum sheet to form a cured coating. The surface composition and morphology of the coating were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The hydrophobicity, wear resistance, and antibacterial properties of the prepared samples were tested. The optimized hydrophobicity was achieved with 10 wt% modification agent and resin-to-ZnO mass ratio of 1:4, exhibiting contact and sliding angles of 168.11° and 7.2°, respectively. Wear resistance was insufficient with a low resin content, while it grew with the increase in the resin content. However, when the resin content was excessively high, the hydrophobicity was reduced because the resin could wrap the modified ZnO nanoparticles and decrease the number of hydrophobic groups on the surface. Compared with the pure acrylic resin coating, the ZnO nanoparticle/acrylic resin superhydrophobic coating demonstrated a significant enhancement in the antibacterial properties.

A Novel Agarwood Resin Inducement Method Using Mycotoxins of Selected Fungal Species

Agarwood is a dark, fragrant, valuable resinous wood produced in Aquilaria and Gyrinops tree species in the family Thymelaeaceae to protect internal tissues from microbial infections. Aspergillus niger and Fusarium solani are well known to induce agarwood resin formation. This study demonstrated for the first time that agarwood resin formation can be induced by the mycotoxins of A. niger and F. solani. Different volumes of mycotoxins extracted from the ASP-U strain (USJCC-0059) of A. niger and the FUS-U strain (USJCC-0060) of F. solani were inoculated into A. crassna trees at 1 m intervals. The impacts of the inoculations were observed through resin content and constituent analysis at 7 months after inoculation. Resin production due to the mycotoxins of ASP-U and FUS-U was restricted to ±20 cm and ±60 cm, respectively, from the inoculation point. Color of the resinous agarwood varied from yellowish-brown to black. The differences in resin content formation due to the different inoculant volumes of ASP-U and FUS-U were statistically significant, and the average resin contents varied from 0.89%-4.44% and 1.24%-9.20%, respectively. GC-MS analysis detected 27 constituents responsible for the characteristic aroma of agarwood resin. Among them, phenyl butanone, agarofuran, agarospirol, β-caryophyllene, alloaromadendrene oxide and (-)guaiene-1(10),11-diene-15-ol were found in all extracts. These are common in commercially available agarwood induced by fungal species. Hence, we demonstrated that the mycotoxins of specific fungal strains can be used for agarwood production. Therefore, chemically synthesized mycotoxins can be used at commercial-scale, eliminating the difficulties of maintaining live fungal cultures for agarwood production.

Effect of Seasonal Decrease in Temperature on the Content and Composition of Guayulins in Stems of Guayule (Parthenium argentatum, Gray)

The guayulins are a family of sesquiterpene compounds that consist of an isoprenoid nucleus substituted either by trans-cinnamic or p-anisic acid, and are present only in the resinous fraction of the rubber plant guayule (Parthenium argentatum, Gray). While the natural role of the guayulins remains enigmatic, they may serve as a defense function against other plants or herbivores by virtue of the accumulation of cinnamic acid. Prior research has suggested seasonal variation in guayulin content, which has been shown to decrease as winter arrives in two different varieties. In the present study, the effect of guayulins has been evaluated in 13 different accessions cultivated under the same conditions during autumn. A general reduction in guayulin content was found in the stems from all varieties between the September and November harvest, which was accompanied by an increase in the resin content. With respect to individual guayulins, while guayulin A was the most prominent member during most of the year, guayulin C had more prominence when temperature started to decrease. In this seasonal period, the production of each member of the guayulin family in the leaves was very balanced.