Polylactide and its Composites on Various Scales of Hardness

Abstract

Polylactide (PLA) has become a widely applied material. Its hardness property has, however, not been a subject of intense study. This study attempts to examine the hardness values of Polylactide and its composites on ten hardness scales. Polylactide composites were developed using three reinforcements (i.e., chitosan, chitin, and titanium powders). The compositing method was the melt-blending technique. Vickers microindentation test was carried out on all the developed samples. The experimental values obtained were related to nine (9) other scales of hardness via an online reference interface. Results showed that the Brinell and Rockwell hardness scales agreed, to a large extent, with the experimental values from several studies. Hence, this work can serve as a reference material on the Brinell and Rockwell hardness values of the unreinforced and reinforced composites considered in this study. The developed materials were also represented on the Mohs scale of hardness with unreinforced PLA having the least value of hardness which corresponds to the value of gypsum on the Mohs scale while the PLA reinforced with 8.33 weight (wt.) % of titanium powder has the highest value of hardness corresponding to the value of a material in-between calcite and fluorite. The hardness values obtained on Shore scleroscope could not agree with the experimental values from various studies. Succinctly, the three particulate fillers increased the hardness properties of PLA. The results of this study would go a long way in helping industrialists and researchers in the correct applications of PLA and its composites.