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36 TECHNOLOGY JUL/AUG 2025 FDM ASIA | www.fdmasia.com

Fabrication Process Of Self-Densified Wood Measurement
First, natural wood blocks were immersed in a boiling lignin The morphologies of the partially delignified wood, the swelling
removal solution of mixed NaOH solution (2.5 mol/L) and wood and the self-densified strong wood were characterised
Na2SO3 solution (0.3 mol/L) for 10 h, followed by immersed by scanning electron microscope.

in boiling deionised water several times to remove residual Quanta 200 SEM was used to observe micron-scale
chemicals. The partially delignified wood blocks were preserved structures; GeminiSEM 500 was used to observe nanoscale
in N,N-dimethylacetamide to remove residual water. structures. The wet delignified wood and swollen wood SEM
Next, partially delignified wood were immersed in N,N- samples were obtained through freeze-drying to maintain
dimethylacetamide at 160 deg C for 1 h to activate wood cellulose. their dimensions.
Then, LiCl (the mass ratio of LiCl and N,N-dimethylacetamide A platinum nanolayer was sputtered on the surface of
is 1꞉9) was added and the swelling reaction was carried out at the samples prior to SEM imaging. The X-ray diffraction
100 deg C without stirring for 1 h, followed by being placed (XRD) patterns of natural wood and self-densified wood were
at room temperature for 10 h. obtained by a diffractometer using Cu-Kα radiation over a

The swelling wood was washed with deionised water several range of 5°–50° at a scanning speed of 0.01°/s.
times to remove residual chemicals. Finally, the swelling wood The chemical changes of wood in delignification process
was air-dried at room temperature and shrank spontaneously and swelling process were studied by Fourier transform infrared
to obtain the self-densified wood. spectroscopy with attenuated total reflection (FTIR-ATR) with
Fabrication Process Of Compressed Densified Wood a scanning range of 3000–500 cm–1. the national renewable
First, the basswood samples were immersed in a boiling energy laboratory (NREL) method was used to quantitatively
aqueous solution of 2.5 mol/L NaOH and 0.4 mol/L Na2SO3 determine the lignin content in both natural wood and self-

for 10 h. densified wood.
Subsequently, they were repeatedly washed with deionised
water to completely remove any residual chemicals. The Mechanical Test
treated wood blocks were then subjected to compression The tensile, three-point bending and compressive properties of
at approximately 3 MPa in a 80 deg C environment for 24 the wood samples were tested using a universal mechanical
h, resulting in a highly compressed densified wood material. testing machine with a video non-contact axial extensometer.
Dumbbell-shaped tensile specimens were laser cut from
the samples (dimension: 80 mm (length) × 2 mm (height) ×
www.tuin.co.uk 6 mm (width). The standard samples were stretched at a

speed of 5 mm/min at room temperature until they fractured.
The dimensions for bending samples were 70 mm by 6
mm by 3 mm. Three-point bending tests were conducted with
the span between the two bottom rollers 34 mm, and the top
roller pressing down at the middle at the speed of 2 mm/min.
For compression tests, the dimensions for samples were
approximately 10 mm long, 10 mm wide and 8 mm thick, and

the samples were compressed along the thickness direction
at a speed of 1 mm/min.