The Effect of Agro-Wastes and Crustacean Fillers on Poly (Vinyl-Acetate) Emulsion Wood Adhesives

Abstract

Cellulosic and crustacean filler materials were used to study their effects on poly(vinyl-acetate) (PVAC) emulsion wood adhesives. The elastoplastic behavior of the filler-treated PVAC emulsion was studied using differential scanning calorimetry and dynamic mechanical thermal analysis. The result revealed that the glass transition temperature (Tg) of the filler-treated polymer is not significantly changed by the addition of the filler materials, whereas the tensile modulus, adhesive hardness, and the stiffness were markedly changed. The viscosity of the emulsions and their performance on wood surfaces were greatly affected by fillers. The cellulosic fillers have high oil-absorption capacity, hence increased viscosity to a greater extent than the case with crustacean-based filler materials, which have faster coalescence but yield mechanically weaker films. The acidity of the fillers influenced the setting time for wood adhesive bonding.

Bonding strength of benuang and duabanga glulams using their barks as phenol formaldehyde-filler

“…Clearly seen, viscosity increased with increasing bark filler ratio. Ogban and Ogbobe [14] stated that the increased viscosity of glue mixtures is due to the high oil absorption ability of cellulosic filler. Figure 1 showed that initial viscosity of glue mixtures with BN bark filler was higher than glue mixtures with DB bark filler.…”

“…Viscosity's adhesive plays an important role in gluing process, since too high or too low viscosity gives a low bonding strength [8]. Too viscous adhesives are difficult to spread out and much of adhesives are remain on wood surface, hence decrease the efficiency contact area between wood and adhesives [14,15]. It leads to weak the bonding strength.…”

“…Inorganic fillers that have been tried to be used for adhesive were calcium carbonate [8], glass particles [9], fumed silica [10], waste marble powder [11], and diatomite powder [12]. Organic fillers generally are biomass waste, such as walnut shell, pinenut shell, ginkgonut shell, coconut shell, periwinkle shell, palm kernel, wood flour, waste rubber, corncob residue, and wood waste ash [5,6,9,[13][14][15][16][17]. Furthermore, bark flour, such as southern yellow pine bark [18], walnut, chestnut, fir, and spruce barks [19,20], alder bark [5,6], beech bark [7], and western red cedar bark [21] are organic filler which are widely used for adhesive.…”