Abstract
Abstract The use of araucaria pine nut shell in polymer composites may increase the pine nut value and help protec araucaria (Araucaria angustifolia) itself, which is an endangered species. The aim of this work is to study the influence of the size of pine nut shell fiber on the mechanical properties of composites made of this shell and polyurethane derived from castor oil. Composites with different polyurethane contents were manufactured with dried untreated pine nut shell sieved through 30 and 50 mesh sieves (0.6 and 0.3 mm, respectively). Composites were shaped by mechanical mixing of the components followed by hot pressing. Properties such as density, water absorption, and flexural strength were measured. Specimens were also characterized by SEM, FTIR, and TGA. The flexural strength of PU/0.3mm pine nut shell composites with 30% PU (wt%) was 57.7 MPa, and their water absorption was 7.37% after 24 hours of immersion.
Highlights
The development of products with low cost, reduced energy consumption and life cycle sustainability is driven by the worldwide concern with the environment and human health[1,2,3]
The different chemical treatments in sisal fibers and the presence of silica nanoparticles resulted in improved mechanical properties and water uptake decrease in the composites, when comparing to HDPE
The aim of this work is to evaluate the effect of pine nut shell size on mechanical, physical, and thermal properties of composites made of castor oil polyurethane and pine nut shell
Summary
The development of products with low cost, reduced energy consumption and life cycle sustainability is driven by the worldwide concern with the environment and human health[1,2,3]. Composites made of biodegradable polymers and reinforced by natural fibers are an attractive option, since these fibers have some advantages when compared to synthetic ones, such as lower density, lower cost, and lower abrasivity during manufacturing. Fernandes et al.[8] analyzed the influence of silica nanoparticles on the compatibility between sisal fibers and high density polyethylene. They observed that thermal properties of HDPE did not change because of the presence of sisal fibers and silica nanoparticles in the composite. The different chemical treatments in sisal fibers and the presence of silica nanoparticles resulted in improved mechanical properties and water uptake decrease in the composites, when comparing to HDPE
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