Modification of eucalyptus pulp fiber using silane coupling agents with aliphatic side chains of different length

Authors: MENDES, RAFAEL - Universidade Federal De Lavras; MENDES, LOURIVAL MARIN - Universidade Federal De Lavras; OLIVEIRA, JULIANO - Universidade De Pernambuco; SAVASTANO JR., HOLMER - Us Pharmacipeia (USP); Glenn, Gregory - Greg; TONOLI, GUSTAVO - Universidade Federal De Lavras

Submitted to: Polymer Engineering & Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2014
Publication Date: 3/28/2015
Publication URL: http://onlinelibrary.wiley.com/doi/10.1002/pen.24065/abstract
Citation: Mendes, R.F., Mendes, L., Oliveira, J.E., Savastano Jr., H., Glenn, G.M., Tonoli, G.H. 2015. Modification of eucalyptus pulp fiber using silane coupling agents with aliphatic side chains of different length. Polymer Engineering & Science. 55(6)1273-1280.

Interpretive Summary: In order to reduce the requirement for non-renewable petrochemicals, the use of plant fibers to develop new and inexpensive reinforced composite materials is being investigated. Most commodity polymers are hydrophobic and are incompatible with plant fibers. In the case of fiber-cement products, fibers within the cement matrix can shrink and swell when exposed to moisture. This can result in a loss of adhesion between the cement matrix and the fiber surface and, consequently, a loss of strength and durability in fiber-cement composites. We were able to modify the surface of eucalyptus fibers in order to increase the adhesion between the cement matrix and the fiber surface. The treatments improved the moisture resistance of the fiber and could be a useful strategy from improving the performance of commercial products such as particle board, fiber-cement and other composites.

Technical Abstract: The objective of this work was to evaluate the effect of three silane coupling agents with different aliphatic chain lengths on the hydrophobicity of eucalyptus pulp fiber. The three silanes coupling agents used (isobutyltrimethoxysilane, methyltrimethoxysilane, and n-octyltriethoxysilane [OTES]) were each tested at three concentrations. Scanning electron microscopy coupled with energy dispersive spectroscopy revealed that the silane coupling agents markedly increased the Si content of the treated fibers. The Si distribution was not completely homogenous but was abundant in the treated samples. The treated fibers had higher contact angles for water and lower moisture adsorption than the control. Of the coupling agents tested, OTES treated fibers had the highest moisture resistance. This was likely due to the greater chain length of the aliphatic side group coupled to OTES. The use of silane coupling agents with alkyl side chains could improve the functional properties of pulp fiber and increase its compatibility with hydrophobic polymers.