High-pressure densification and hydrophobic coating for enhancing the mechanical properties and dimensional stability of soft poplar wood boards

Journal of Wood Science

Official Journal of the Japan Wood Research Society

Table 1 Average compress ratios and density of wood samples after various HP densification for 30 s

Pressure (MPa)	Original Thickness (mm)	Thickness after densification (mm)	Compression ratio (%)	Density (kg/m³)
Pressure (MPa)	Original Thickness (mm)	Thickness after densification (mm)	Compression ratio (%)	Before densification	After densification
25	29.7 ± 0.11^a	18.8 ± 0.53^b	36.8 ± 1.05^a	450 ± 50^a	700 ± 60^b
50	29.7 ± 0.11^a	17.6 ± 0.72^c	40.7 ± 0.89^b	450 ± 50^a	840 ± 90^c
75	29.7 ± 0.11^a	16.4 ± 0.41^d	44.8 ± 1.12^c	450 ± 50^a	860 ± 80^d
100	29.7 ± 0.11^a	15.8 ± 0.21^e	46.7 ± 1.02^d	450 ± 50^a	910 ± 60^e
125	29.7 ± 0.11^a	14.3 ± 0.10^e	51.9 ± 0.92^d	450 ± 50^a	960 ± 20^e

Measured values are represented as mean ± standard error of 15 replicates. Means followed by the different letters (a, b, c, d and e) are significantly different among original thickness and thickness after densification (p < 0.05). Means followed by the different letters (a, b, c and d) are significantly different among CR (p < 0.05). Means followed by the different letters (a, b, c, d and e) are significantly different among density (p < 0.05)