Impact of delignification on morphological, optical and mechanical properties of transparent wood

Transparent wood was prepared from basswood (Tilia) subjected to various degrees of delignification prior to its polymer impregnation. The chemistry and surface morphologies of wood samples were evaluated. The optical properties such as surface color, optical transmittance and optical haze of natural wood and each transparent wood product and their mechanical properties were monitored in order to better understand the influence of delignification. Experimental results indicated that the lightness of transparent wood increased with delignification, while the redness and yellowness decreased. The transparent wood exhibited a maximum optical transmittance of 61% at 800 nm with 9% lignin content and also possessed enhanced visual optical haze at different levels of delignification. In addition, transparent wood had a higher tensile strength than natural wood and displayed a maximum tensile strength up to 171.4 MPa with 15% lignin content among these transparent wood products pretreated with delignification. Our findings offer a view into how transparent wood can be produced to fit certain levels of optical and mechanical properties.