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Mechanical particle size reduction methods as potential interfacial optimization alternative for a low-carbon particulate reinforced marine bio-composite

Echeverria, Claudia, Pahlevani, Farshid, Sahajwalla, Veena
Journal of cleaner production 2019 v.221 pp. 509-525
Bivalvia, Ecklonia, biocomposites, construction industry, crystal structure, energy use and consumption, grinding, macroalgae, modulus of rupture, particle size, polypropylenes, powders, prototypes, quantitative analysis, sawdust, slabs, surface roughness, waste wood, wettability
The materials particle size reduction is an efficient, but often a time and energy intensive operation. Targeting the optimization of composite manufacturing process through low-cost materials selection, production efficiency, and minimization of energy consumption, this study investigated two dry particle size reduction methods –slow grinding and fast collision milling– as a potential one-step non-chemical filler/matrix compatibilization alternative, for a Marine/Polypropylene Bio-composite sheet material, for building applications. Two local coastal litter materials from Sydney, kelp brown algae (Ecklonia spp.) and bivalve mollusc seashell (Verenidae spp.) were selected as combined multi-functional bio-fillers. Four bio-composites prototypes were manufactured by isothermal hot-compression method, formulated to represent the most relevant permutations of the powders, with filler/matrix 60/40 wt%, respectively. Mixed wood waste sawdust was incorporated as secondary reinforcement to the blend, as a third of the total filler load. 20 specimens were prepared and tested. The effect of the size reduction methods on the particles properties were characterized by bulk, and surface sensitive qualitative and quantitative analyses. The surface roughness, wettability, fracture surface, and mechanical properties of the bio-composite prototypes are reported. The overall results indicated four distinctive filler morphologies were obtained: laminar, flakes, slabs, oblong particles, in which the physicochemical properties, topographical properties, and crystal structure greatly differed. The prototype panels manufactured with mechanically milled powders presented the peak mechanical properties for flexural strength, attributable to an enhanced materials interfacial behaviour. Additionally, as result of the different powder properties, competitive advantages were attained for moisture resistance and appearance grade, thus as potential candidates for architectural interior applications.