Short notes: The low-velocity impact response of bio-composites

In this paper, an experimental investigation on the low-velocity impact response of wood-based bio-composites is presented. This study is to map the suitability of plant-based materials instead of petroleum-based plastic as a constituent raw material in composites. Wood-based composites panels were made from southern yellow pine (SYP), corn starch (CS), and methylene diphenyl diisocyanate (MDI) using a Diefenbacher hot press. The impact performance of the specimens was evaluated in terms of energy absorption capacity. Five types of bio-composites were prepared with varying compositions with SYP: 4% MDI; 2% CS and 2% MDI; 2% CS and 4% MDI; 4% CS and 4% MDI. These samples were prepared at two different manufacturing pressures. The bio-composite produced with higher manufacturing pressure had the highest absorbed energy among five different types of bio-composites, this shows that material behavior at impact loading is strongly dependent on the manufacturing pressure during fabrication.

Dynamic and damping properties of novel bio-composites using the hammer excitation vibration technique

The dynamic and damping properties of nine different wood-based bio-composites at varying volume fraction of Corn starch (CS), methylene diphenyl diisocyanate (MDI), microcrystalline cellulose (MCC), processing time and pressure have been studied. The samples used for the study consisted of southern yellow pine particles with 2% Corn starch (CS), 4% methylene diphenyl diisocyanate (MDI); 4% CS 4%MDI; – 4% MDI; – 2% CS 2% MDI; – 4% CS 4% MDI; – 2% microcrystalline cellulose (MCC) 4% MDI; – 4%CS2% MDI; – and 1% MCC 4% MDI; – (all on a solids basis). The panels were manufactured using a Dieffenbacher hot press at a temperature of 185oC. The dynamic and damping properties were determined using hammer excitation vibration technique. The responses were obtained from frequency and time domain for the fundamental natural frequency (fn), and the results obtained were consistent. The panel manufactured with 4% MDI and formed at relatively high pressure (10.5 MPa) had the highest average storage modulus (E’), and this shows that increasing manufacturing pressure and density of material contributed to the high elasticity of the material. The panel produced with 2% CS and 2% MDI had the highest damping ratio (ξ) and Loss factor (η) when compared with other wood samples, and this demonstrates that the CS contributed to the high damping of the material.