Wettability of Dendrocalmus asper under Various Heating Time during Composites Making Process

Abstract

Bamboos are often used due to their abundance, fast growth rate, cheap price, ductility, and formability in the sector of transportation, musical instrument, cooking ware, etc. For construction purposes, Dendrocalamus asper, (locally known as “Bambu betung”), is used as bamboo composites. The properties of bamboo are highly improved by using phenolic resins (phenol-formaldehyde) as an adhesive in bamboo composites. Bamboo is stronger and more susceptible to any liquid. The liquid is the most common enemy to plant-based structure due to the softening effect. Thus, the wettability of bamboo is an important matter as it indicates the ability of a liquid to spread and penetrate on the surface. The objective of this study was to analyze the effect of various heating times to wettability properties of heat-treated D. asper strands during the bamboo-composite making process. Before testing, the bamboo was cut, cleaned, and sand-grinded. The bamboo strands were heated at 140°C for 1, 2, and 3 hours. Then, the surface of bamboo was evaluated by measuring the contact angle based on the sessile drop method. The constant contact angle was obtained by calculating the regression formula between time (t) and contact angle (θ). The wettability was indicated by the value of K. The color of heat-treated bamboo strands was measured by portable color difference meter model CDX 105 and characterized by CIE Lab. The results showed that the longer the holding time, the surface became more hydrophobic, showed by a highercontact angle. Longer heating gives more time to the resin to spread more evenly into the pores of bamboo so that the hydrophobicity of bamboo composites is increased. The lightness value (L*) of heat-treated bamboo strands tended to decrease with increasing temperature and time of heat treatment. To conclude, for further making the process of bamboo composites using D. asper, we recommend curing the composites for 3 hours.

Durability to Natural Weathering of Methylene Diphenyl Diisocyanate-Bonded Bamboo Oriented Strand Board

“…In addition, as the exposure time increases, the MC value will increase (Maulana et al 2019). This phenomenon can be attributed to BOSB being composed of hygroscopic bamboo strands that have the ability to absorb moisture (Baiti et al 2021a;Murda et al 2022b;Sipahutar et al 2021).…”

Treatment of Bamboo for Sustainable Construction Practise: A Comprehensive Review

“…2.5. Heat treatment [52][53][54] Bamboo heat treatment entails treating bamboo to high temperatures in a controlled setting in order to change its physical and mechanical properties. This procedure can improve bamboo's stability, durability, and resilience, making it appropriate for a variety of uses.…”

“…Furthermore, heat treatment might affect the colour of bamboo. Long-term exposure to high temperatures can darken the bamboo, causing it to change appearance [54]. Thermal breakdown of organic pigments and the creation of new chromophores are principally responsible for the colour change.…”

“…Heat treatment is the process of treating bamboo to high temperatures in order to change its chemical and physical qualities. This procedure improves its dimensional stability, decreases moisture absorption, and increases decay resistance [20][21][22][23][24][25][26][27]. Alkali treatment, on the other hand, removes starches and sugars from bamboo, making it less appealing to insects and more resistant to deterioration [28][29][30][31][32][33].…”

Physical and Mechanical Properties of Bamboo Oriented Strand Board Under Various Post-Thermal Treatment Duration

“…Increasing cellulose crystallinity inhibits the water molecules' accessibility to hydroxyl groups (Kasemsiri et al 2012;Lee et al 2018). Baiti et al (2021) stated that the surface bamboo strand was heated longer and is more hydrophobic. The MOE and MOR values of thermally-modified BOSB decreased with increasing treatment duration.…”