Effects of wood flour content and heat treatment on the dynamic mechanical and impact properties of LDPE/red balau ( Sho
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Effects of wood flour content and heat treatment on the dynamic mechanical and impact properties of LDPE/ red balau (Shorea Dipterocarpaceae) composites Ruth A. Lafia‑Araga1 · Aziz Hassan2 · Rosiyah Yahya2 · Normasmira Abd Rahman2 · Fauzanie Md Salleh3 · Ganiyat Olusola Adebayo4 Received: 26 January 2020 / Revised: 27 June 2020 / Accepted: 18 September 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Red Balau saw dust was heat-treated at 180 °C and 200 °C for one hour and compounded with low-density polyethylene, LDPE, at 9, 20 and 37 wt%. The compounded materials were injection moulded into test specimens. Charpy impact assessment of the notched samples of the composites revealed that the peak load, P, and the critical stress intensity factor, Kc, increased with wood content and treatment temperature. While the energy to failure, W , and the critical strain energy release rate, Gc, decreased with wood content, the values were highest in composites made from wood flour treated at 180 °C and reduced in 200 °C treated wood composites. This behaviour revealed that heat treatment of wood flour at the 200 °C resulted in poorer impact properties of the composites. Dynamic mechanical analysis showed an increase in storage and loss modulus of composites made from untreated wood flour relative to the heat-treated ones. Tan delta values were also found to reduce in the heat-treated wood composites as a result of decreased damping. Heat treatment of wood flour at appropriate temperature enhanced both the mechanical and dynamic mechanical properties of the composites. Keyword Heat treatment · Wood fibre modification · Impact properties · Dynamic mechanical analysis · Injection moulding
* Ruth A. Lafia‑Araga [email protected] 1
Department of Chemistry, School of Physical Sciences, Federal University of Technology, Minna 920006, Niger State, Nigeria
2
Polymer and Composite Materials Research Laboratory, Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
3
Chemisty Division, Centre for Foundation Studies in Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
4
Standards Organisation of Nigeria, Operational Headquarters, Lekki Peninsula Scheme 1, Lekki 101233, Lagos, Nigeria
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Polymer Bulletin
List of symbols E′ Storage modulus E′25 °C Storage modulus at 25 °C E′− 100 °C Storage modulus at −100 °C E′′ Loss modulus E′′max Peak maximum of the loss modulus E’′25 °C Loss modulus at 25 °C ′′ T𝛽E Temperature at maximum value of E′″ δ Phase angle Tanδ Loss factor Tanδ25 °C Loss factor at 25 °C Tanδmax Maximum value of Tan δ peak σ Dynamic stress ɛ Dynamic strain SEN Single edge notch a Notch or crack length a/D Notch-to-depth ratio P Peak load Kc Critical stress intensity factor Y Geometry factor σc Critical stress for crack propagation S Support span S/D Span-to-depth ratio W Fracture energy Gc Critical stress release rate ϕ Geometrical correction factor
Introduction There has been
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