Improvement of the properties of hardboard with heat treatment application

Abstract

The attempt to face the limitations of wood-based materials, especially concerning the relationship with water, is still a considerable gap in research on this subject. The present work proposes the accomplishment of thermal treatment in fiberboard-type hardboard, using different temperatures and times, to evaluate the effect on the physical-mechanical properties. The parameters of the heat treatment were temperatures of 120 and 160 °C and times of 20 and 40 min. The hardboards were individually heat treated in a kiln. The characterization was performed from physical tests such as bulk density, moisture content, water absorption (2 and 24 h), thickness swelling (2 and 24 h); and mechanical properties of flexural strength. The treatment with a temperature of 160 °C for 40 min showed the lowest values of water absorption in 24 h (34%). Thickness swelling was lower compared to control, for all the treatments applied. Regarding flexural strength, the treatment that adopted the 160 °C for 20 min showed the highest MOR value (26.3 MPa). In general, the performance of heat treatments positively influenced the physical and mechanical properties of the hardboards, being an interesting alternative in the development of products for applications in internal environments.

Ecological adhesive based on cassava starch: a sustainable alternative to replace urea-formaldehyde (UF) in particleboard manufacture

“…Hence, the MoE values obtained were higher than the required limit values given by ANSI A208.1 [47] and JIS A5908 [48] standards (1550 MPa) for lowdensity particleboards (Figure 4A). According to COSTA et al [49], the mechanical properties of the modulus of rupture and elasticity are fundamental for measuring resistance and analyzing the elastic performance of materials subjected to loads. MoR values recorded for all the adhesive combinations were higher than the required MoR limits set by the ANSI A208.1 [47] for construction and other fitments (Figure 4B).…”

Efeito da temperatura e pressão nas propriedades da liga de titânio Ti-6Aℓ-4V produzida a partir da metalurgia do pó

“…Os dados foram organizados em planilhas e posteriormente, seguindo procedimento metodológico proposto por COSTA et al [18] e MARTINS et al [19] aplicou-se o teste de Shapiro-Wilk para verificação da normalidade e o teste de Levene para verificação heterogeneidade. Seguidamente, aplicou-se uma análise de variância (ANOVA) e, no caso de diferenças estatísticas, foi realizado um teste de Tukey a 95% de significância (p-valor < 0,05) utilizando o software livre Sisvar.…”