Bamboo Strand Research Articles

The physical, mechanical and durability properties of sorghum bagasse particleboard by layering surface treatment

The decrease of wood supply leads to find out the alternative raw material for particleboard production derived from non-woody cellulose materials, one of the promising material is sorghum bagasse. However, the strength properties of particleboard manufactured from this biomass tend to be low. This research was to evaluate physical, mechanical and durability properties of sorghum bagasse-particleboard (SBP) which was layered by several materials. Previously, sorghum bagasse as particle board core and materials for layers such as woven of bamboo bark, woven of barkless bamboo, bamboo strand, Meranti and Eucalyptus veneer were oven dried at 103 °C to reach 4% moisture content with 10% Urea formaldehyde resin. After particle and adhesive blending step, furnish was used as core with layer materials as surface. Subsequently, mat was pressed at 130 °C for 10 min with 30 kg cm−2. Physical and mechanical properties evaluation refers to JIS A 5908-2003, while their durability properties were evaluated by grave yard test. The results showed that surface layer treatment improved the bending properties presented by increasing of modulus of rupture and modulus of elasticity value of surface layer treatment of SBP compared to untreated ones. However, their thickness swelling has not been met standard of JIS A 5908-2003 yet. Furthermore, surface layer treatment with woven of barkless bamboo showed the best physical, mechanical, and durability properties.

Mechanical evaluation for laminated bamboo lumber along two eccentric compression directions

To evaluate the mechanical performance under two eccentric compression directions, 80 laminated bamboo lumber (LBL) column specimens were tested and analysed. Mechanical properties along two directions were compared. Bamboo nodes and drill hole are two main failure reasons for the specimens under two eccentric directions. More crack layers appeared for radial eccentric direction group specimens due to the layer structure. No matter which eccentric directions they are, the lateral deflection curves are close to the sine line, and the strain across the cross section of the LBL column for each specimen is basically linear throughout the loading process, following standard normal section bending theory. The mechanical properties for two directions are similar with each other and could follow the same design rules. Although the mechanical properties are similar for both LBL columns and parallel bamboo strand lumber (PBSL) columns as a whole, there are still some clear performance differences between the two kinds of materials. Combined all the test data under two eccentric directions, an equation for calculating the radial eccentricity influencing coefficient $$ \varphi_{\text{e}} $$ of LBL columns is proposed. The calculation results obtained from the equations give a good agreement with the test results.

Eccentric Compression Performance of Parallel Bamboo Strand Lumber Columns

The influence of eccentricity ratio on the behaviour of 50 parallel bamboo strand lumber (PBSL) column specimens was studied under eccentric compression. The load-strain and load-deflection relationships were obtained from column tests, and the detailed failure modes for all specimens are reported. The eccentricity ratio is the main influencing factor on the bearing capacity of the columns, and the ultimate load values decreased with an increase of the eccentricity ratio. Both the ultimate middle deflection values and the absolute ultimate longitudinal strain values initially increased with the increase of the eccentricity ratio, and then stabilized or decreased slightly when the eccentricity ratio was bigger than approximately 0.8. The absolute ultimate lateral strain values for both face A (bracket side or compression side) and face C (tension side) performed similarly with the increasing of eccentricity ratios, increasing initially and then stabilizing or decreasing slowly. An equation for calculating the eccentricity influencing coefficient of PBSL columns is proposed. The calculation results obtained from the equations agreed well with the test results.

Parameters of Strand Alignment Distribution Analysis and Bamboo Strandboard Properties

Strand length, free-fall distance (FFD), and plate spacing was varied to control the strand alignment distribution of strandboard. To determine the strand angle distribution, photographs of strands were recorded as digital image data, and strand angle analysis was conducted using a modified von Mises distribution function. A part of this measurement was used as a reference for the alignment in the board produced. The results of strand alignment distributions showed that the k value was a function of strand length, FFD, and plate spacing. The k value can be improved by adjusting the plate spacing closer to the strand width, shortening the FFD, and using long strands. The power equation model can describe those relations. The bending properties and linear expansion (LE) were greatly affected by the FFD and the plate spacing. The use of low FFD and narrow plate spacing improved the bending properties. The decreasing bending properties in the parallel direction could be comparable to the increasing ones in the perpendicular direction. The contribution of bamboo strand in the longitudinal direction affected these results.

Self‐Assembly of Ternary Particles for Tough Colloidal Crystals with Vivid Structure Colors

Self‐assembly of colloidal spheres is the most frequently used method for structural colors, but the chroma of the structural colors is usually so low that people cannot observe it under natural conditions. This paper presents a facile method for fabrications of vivid structural colors by doping carbon black into the self‐assembly of colloidal polymer spheres and nanosilica particles. This approach can generate very gorgeous structural colors which can be very easily seen under natural conditions. The fabrication conditions for the self‐assembly of composite dispersions of polymer/silica/carbon black were optimized to obtain colloidal crystals with vivid colors. Thus, robust mechanical properties, large‐scale, and brilliant structural colors can guarantee the obtained crystal films to find practical applications, which are demonstrated by the fact that the successful applications of structural colors beautify the original simple and tedious surface of bamboo strand board (BSB).

PENGARUH KOMPOSISI FACE-CORE TERHADAP SIFAT FISIK DAN MEKANIS ORIENTED STRAND BOARD DARI BAMBU DAN ECENG GONDOK

The effect of particle composition made of bamboo and water hyacinth on the dimensional stability and mechanical properties of resulted oriented strand boards (OSB) were investigated. Three layered boards were made from bamboo and water hyacinth in which bamboo strand was used as face/back layer and water hyacinth strand was used as core layer. The boards were manufactured using three levels of bamboo and water hyacinth compositions (50:50, 60:40 and 70:30) with 6 % isocyanate based on the strand oven dry weight. The results showed that dimensional stability of the OSB decreased with the increase of composition of water hyacinth strand on core layer. A higher composition of bamboo strand as face/back layer compared to water hyacinth strand resulted in increased modulus of elasticity and internal bond strength, but decreased the modulus of rupture. The bamboo and water hyacinth composition of 70:30 compositions showed better properties than other compositions. Key words: Bamboo, water hyacinth, composition, OSB

Self-assembly of colloidal spheres and application as solvent responding polymer film

It is the first time to fabricate and apply responsive colloidal crystal (CC) films on biocomposite material – bamboo strand board (BSB). The responsive film can be easily prepared directly through the self-assembly of soft colloidal polymer spheres containing hydrophilic monomers at ambient pressure and temperature without complicate equipment. In this approach, soft colloidal polymer spheres are synthesized by emulsion polymerization using polymerizable emulsifier. Then, the polymer latex is loaded onto the surface of BSB. The colloidal polymer spheres can directly self-assemble into a robust and transparent colloidal crystal (CC) film on BSB. Neither soft matrix nor posttreatment is needed. Compared with the traditional responsive CC, the polymer film on BSB not only had sensitive response behaviors but also had good reversibility and mechanical strength, which would provide a new method for fabrication and application of responsive CC.

Some Importance Properties of Bamboo-Wood Strand Board

Bamboo has gained increasing attention as an alternative raw material for use in the manufacture of composite boards. Three layered boards were made from bamboo strand and wood particle to evaluate the effects of resin content and layer structure on the properties of bamboo-wood strand board. Bamboo strand was used as face/back layers, and wood particle was used as core layer. The boards were fabricated using urea formaldehyde resin with three dosage levels ranging from 3 to 9 percent for bamboo strand and 6 percent resin content for wood particle. The mechanical properties and dimensional stability of bamboo-wood strand board were evaluated, and the results were summarized as follows. The bending properties, internal bond (IB) strength and dimensional stability of the board increased with increasing of resin content. Using bamboo strand as face/back layered, slightly increase bending properties of bamboo-wood strand board. However, the modulus constant and IB strengths after boiling test could not be observed. It indicates that urea formaldehyde was not suitable for bamboo-wood strand board.

Effect of board density and layer structure on the mechanical properties of bamboo oriented strandboard

This study examined the effects of density and layer structure on the mechanical properties and dimensional stability of strandboard manufactured from moso bamboo (Phyllostachys pubescens). The strandboard was fabricated in a laboratory at five densities and three different structures including a randomly oriented homogenous board, a unidirectionally oriented homogenous board, and a three-layered board with a cross-oriented core layer (BOSB). Bamboo strand alignment distribution could be predicted using the von Mises distribution function. Bending properties increased with increasing density and were affected by layer structure. The modulus of rupture (MOR) of the threelayered board in the parallel direction increased remarkably compared with the random board MOR; in the perpendicular direction, it exhibited less strength reduction. Elastic properties of the three-layered board could be predicted using elastic constants of the unidirectional board. Internal bond strength (IB) was greatly affected by density, but the layer structure effect did not appear in IB. Linear expansion per unit moisture change ranged from 0.017 to 0.022 for random and three-layered boards; these values are comparable with or lower than values for commercial board.