Preparation and Characterization of Outdoor Bamboo-Fiber-Reinforced Composites with Different Densities

Abstract

aOutdoor bamboo-fiber-reinforced composites (OBFRCs) with four different densities were prepared, and the microstructure and physicomechanical properties of pristine samples were evaluated. In addition, the surface color, glossiness, roughness, water absorption, and wettability of the samples were tested to investigate the effects of panel density on the extent of surface weathering due to ultraviolet radiation. The results showed that the OBFRCs exhibited excellent physical and mechanical properties, which improved with increasing density. However, increases in the density led to decreases in the hygroscopicity and dimensional stability of the OBFRCs. After weathering, the surface contact angle and surface roughness increased, and the dimensional stability improved. The surface glossiness, water absorption, and surface free energy decreased. A higher density resulted in improved color stability, which suggested that density played an important role in determining surface photodegradation properties. Thus, densityincreasing treatments had positive effects on the physical and mechanical properties as well as the color stability and wettability of the OBFRCs, but they may negatively affect the roughness and dimensional stability. Based on service-performance and cost-minimization considerations, 1.1 g/cm 3 was determined as the most appropriate density for general applications.

Improvement of surface photostability of bamboo scrimber by application of organic UV absorber coatings

“…On the other hand, the surface material of samples B-D is the coating main component, namely, the resin, so the photodegradation of the hydrophobic surface of samples B-D may be the major reason which results in a decrease in the water CA. The water CA of aged sample A shows a sharp deterioration after the water droplet stayed for 8 s on the sample surface, the rate of descent of aged sample A was greater than unaged sample A; a similar result was observed by Rao et al[1]…”

“…The substrate OBS was prepared according to the standard procedure [1]. Four-year-old moso bamboo (Phyllostachys pubescens Mazel) culms were harvested at a plantation located in Anhui Province in eastern China.…”

“…The colour changes are related to chemical changes such as the degradation of OBS lignin and coatings, which degrades the aesthetics of the material surface [1]. The colour changes in response to the UV irradiation of the surfaces of the samples with the different treatments are shown in Fig.…”

“…The favourable properties of bamboo scrimber products in terms of dimensional stability, natural colour, elegant texture, and ease of processing has led to its widespread application. Further, bamboo scrimber is considered to be a good biological material for outdoor application [1]. However, when it is exposed to outdoor conditions, such as solar radiation, moisture, oxygen, high temperature, and bacteria and fungi, its exterior tends to undergo discolouration, decreasing the glossiness and increasing the roughness.…”

Progress of Bamboo Recombination Technology in China

“…In the process of molding, the microstructure, chemical composition, physical and mechanical properties of bamboo, and resin have changed significantly. The results showed that the parenchyma, vessels, and fibers of bamboo were compacted to different degrees, and the cell walls were folded or even crushed [22,[45][46][47][48]. Phenolic resin was redistributed and cured under hygrothermal condition with high pressure, forming the macrobonding interface between the resin and the substrate surface, the microscale interface between the resin and the vessel as well as the cell cavity of parenchyma cells, and the nanoscale interface between the resin and the cell wall of parenchyma cells [49].…”