基于碳量子点的荧光透明木的制备与性能

Preparation and properties of carbon quantum dot based fluorescent transparent wood

碳量子点(CDs)是一种新型荧光功能材料,将其作为改性剂复合而成的材料具有光致发光性能。本研究以木质素制备碳量子点并将其分散在脱木质素杨木(DW)中,使用光固化树脂进行填充,获得具有光致发光性能的荧光透明木材(FTW)。这种荧光透明木材在透明橱窗材料与紫外光转化为可见光等方面将有着广泛的应用前景。分别对碳量子点的结构组成与荧光性质以及荧光透明木材的光学性质与力学性能进行了测试与分析。结果表明,以木质素为碳源,尿素为掺杂剂制备的碳量子点具有石墨化碳核,表面有多种官能团并表现出较为均一的粒径。荧光性能测试结果表明,碳量子点有着优异的光学性质与荧光稳定性。电镜与能谱分析结果表明,碳量子点均匀附着在脱木质素杨木的木纤维细胞壁及导管壁表面。所制备的荧光透明木材(FTW)在波长为365 nm的紫外灯激发下呈均匀的蓝色荧光(发射波长为438 nm)。此外,使用光固化树脂制备透明木材可以缩短透明木材的固化时长,以简化透明木材的制备工艺。光学性能测试结果表明,所制备荧光透明木材的透光率达到了86.1%,光学雾度为73%。机械性能测试结果表明,相较于未改性杨木,荧光透明木材具有更大的应力值(68 MPa)与应变量(27.4%)。

Carbon quantum dots(CDs) are a new type of carbon nanomaterials, which can be used as a modifier to prepare composite materials with excellent photoluminescence properties. In this study, carbon quantum dots were prepared using lignin as the precursor and dispersed in delignification of poplar wood. The delignified wood(DW) with carbon quantum dots was filled with a UV-curing resin, and the fluorescent transparent wood(FTW) with photoluminescence properties was obtained. The prepared fluorescent transparent wood could have a wide range of application prospects in the fields of transparent window materials and the conversion of ultraviolet light into visible light. The microscopic morphology, structural composition and fluorescent properties of the obtained carbon quantum dots and the optical properties and mechanical properties of the fluorescent transparent wood were examined and analyzed in this study. The results showed that the carbon quantum dots prepared with lignin as the precursor and urea as the dopant had a graphitized carbon core, a variety of functional groups on the surface and a relatively uniform particle size. Fluorescence performance characterization results showed that carbon quantum dots had excellent optical properties and pH fluorescence stability and photobleaching stability. Electron microscopy and energy spectroscopy showed that the well-preserved porous structure composed of the cellulose skeleton, and the carbon quantum dots were uniformly attached to the surface of wood fiber cell walls and the vessel walls of the delignified poplar wood. The prepared fluorescent transparent wood(FTW) showed uniform blue fluorescence(emission wavelength of 438 nm) under excitation of ultraviolet lamp with a wavelength of 365 nm, the standard chromaticity coordinate of the International Commission on Illumination(CIE) was(0.16, 0.10). In addition, the preparation of the transparent wood with UV-curing resin simplified the preparation process and shorten the curing time. The optical performance test results showed that the light transmittance of the prepared fluorescent transparent wood reached 86.1%, and the optical haze was 73%. The mechanical performance test results showed that, compared with the unmodified poplar, the fluorescent transparent wood had improved mechanical properties, i.e., the stress of 68 MPa and strain of 27.4%.