Laminated Transparent Woods with Adjustable Optical and Enhanced Mechanical Properties

Abstract

Transparent wood is promising for energy‐saving buildings, but its poor mechanical properties in transverse direction dramatically limit its applications. To resolve the problem, a novel processing technology is developed to fabricate laminated transparent woods. Various kinds of transparent woods are prepared by stacking partially impregnated woods in different styles and then compressing them. The wood template contents in these transparent woods are significantly increased by the partial impregnation compared with traditional full impregnation. The influence of lamination structures on the properties of the transparent woods is also evaluated. As the number of laminate layers increases from one to three, the optical transmittance reduces from ≈70% to 44%, respectively, while the haze increases from 32% to 66%. The isotropy of scatter light distribution could be achieved by controlling lamination structures for more uniformity in indoor illumination. The mechanical properties of the transparent woods are dramatically enhanced, and the highest tensile and flexural strength can reach 134.0 and 192.3 MPa, respectively. Additionally, the direction‐dependence of mechanical strength is reduced by cross‐laminating. The adjustable optical features, excellent mechanical strengths, and low thermal conductivity endow the prepared transparent woods a promising candidate for energy‐efficient buildings applications.

Transparent Bamboo with Multiple Light Transmittance Levels, Fiber Textures, and Colors Based on the Gradient Structure of Bamboo

“…Anisotropic materials can be made more isotropic by adjusting the lamination type in composites. [ 5 ] This difference in mechanical strength is appealing for practical applications, and the mechanical strength of compressed TB can be designed by controlling the lamination structure. The relatively good mechanical properties of TB ensure its feasibility for product, decoration, and structural design.…”

“…Moreover, it has advanced multifunctional potential and broad application prospects in energy‐saving buildings, optoelectronics, lighting design, and other high value‐added fields. [ 4–7 ] Various functional TWs, such as heat‐shielding TW, [ 8 ] magnetic TW, [ 9 ] flexible and conductive TW, [ 10 ] aesthetic TW, [ 11 ] and patternable TW, [ 12 ] have been developed. In addition, TW can effectively absorb sunlight and therefore can be used in energy‐saving interior lighting.…”

Fabrication, Functionalities and Applications of Transparent Wood: A Review

“…[29b] The resultant elastic moduli and tensile strengths after lamination might be predicted by classical lamination plate theory and simple rule of mixtures, respectively. [52] One significant justification for the potential of TW to replace common glasses is its toughness (≈3.2 MJ m −3 ), which can be 30 times higher to that of common glass (≈0.1 MJ m −3 ). [65] Unlike common silica-based glass, TW will not shatter into sharp pieces in case of strong sudden impact, eliminating potential safety issues.…”

“…[ 29b ] The resultant elastic moduli and tensile strengths after lamination might be predicted by classical lamination plate theory and simple rule of mixtures, respectively. [ 52 ]…”