Transparent Wood Composite With Selective Delignification
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Solution Overview
Problem
Existing transparent wood composites require substantial lignin removal, compromising the integrity of the cellulose-based microstructure and mechanical strength, and involve lengthy processing times and chemical use.
Innovation Solution
A contiguous wood block is subjected to selective lignin removal and UV-assisted photocatalytic oxidation, followed by infiltration with an index-matching polymer, to create transparent and translucent sections that retain natural patterns and enhance mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If substantial lignin removal is performed to create transparent wood composites, then transparency is improved, but mechanical strength and microstructure integrity deteriorate
Solution Approach 1:
The patent applies selective delignification to create different optical properties in different sections of the wood. Earlywood sections are delignified to be transparent while latewood sections retain lignin to maintain mechanical strength and provide structural support. This local differentiation resolves the contradiction between transparency and strength by optimizing each region for its specific function.
Solution Approach 2:
The patent creates a composite structure where delignified cellulose sections (transparent) are combined with lignin-retaining sections (opaque but strong). The resulting wood composite exhibits both transparency in functional areas and mechanical integrity in structural areas, resolving the contradiction through material composition optimization.
2Illumination intensity
If conventional delignification methods are used to achieve transparency, then transparency is improved, but processing time and chemical consumption increase
Solution Approach 1:
The patent exploits the natural structural differences between earlywood and latewood sections to achieve selective delignification. Earlywood sections with lower density and higher porosity are preferentially delignified by chemical solutions, while latewood sections resist delignification due to their denser structure. This natural differentiation accelerates the process compared to attempting to delignify uniform wood structures.
Solution Approach 2:
The patent modifies delignification parameters including chemical concentration, treatment temperature, and exposure time to optimize the selective removal of lignin from earlywood sections while preserving latewood sections. By tuning these parameters, the process achieves transparency in required sections within reduced processing time.
3Illumination intensity
If complete delignification is performed to maximize transparency, then transparency is improved, but chemical consumption and environmental impact increase
Solution Approach 1:
The patent performs delignification only in earlywood sections where transparency is needed, rather than treating the entire wood block. This localized approach significantly reduces chemical consumption compared to complete delignification, while still achieving the desired optical properties in functional areas.
Solution Approach 2:
The patent applies partial delignification - removing lignin from earlywood sections sufficient to achieve transparency without over-treating the material. This partial action approach reduces chemical consumption and environmental impact while maintaining the necessary optical properties.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method produces transparent wood composites with improved mechanical strength, reduced chemical and energy consumption, and faster processing times, enabling large-scale manufacturing for applications like energy-efficient buildings and optical devices.
Implementation Method 1
the contiguous wood block can be infiltrated with a liquid oxidation agent, such as hydrogen peroxide, and then subsequently exposed to UV radiation to cause a chromophore of lignin within the wood block to be removed therefrom
Implementation Method 2
Subsequent infiltration of the chemically-treated wood block with an index-matching polymer converts the delignified sections to be substantially transparent
Data Source
AI summary
In some embodiments, a material comprises a contiguous block of chemically-modified wood infiltrated with an index-matching polymer. The contiguous block has a first section that is substantially transparent to light and a second section that is translucent or opaque. The first section can have a lower lignin content than the second section. Alternatively, the first section can have a chromophore state altered from that of the wood in its natural state, and the lignin in the second section can retain a chromophore state of the wood in its natural state. In some embodiments, a material comprises a section of wood chemically-modified such that chromophores of lignin within the wood in its natural state are altered or removed, and the section retains at least 70% of the lignin of the wood in its natural state. Methods for forming such materials are also disclosed.