Toughness improvement of poly(lactic acid) by the addition of pre-crosslinked powdered nitrile rubber/CaCO 3 for thermoforming molding

• Published in: Journal of elastomers and plastics 2021-10, Vol.53 (6), p.565-582
• Main Authors: de Almeida, Janaína Fernandes Moreno, de Oliveira, Amanda Gerhardt, de Sousa, Ana Maria Furtado, Fernandes, Teresa Maria Dias, Bertolino, Luiz Carlos, Pacheco, Elen BA Vasques, da Silva, Ana Lúcia Nazareth
• Format: Article
• Language: English
• ISSN: 0095-2443; 1530-8006
• DOI: 10.1177/0095244320958108

Polylactide (PLA) is an eco-friendly biodegradable thermoplastic with excellent processability, demanding less energy to be produced compared to the petroleum-based polymers. However, PLA has drawbacks that impose some restrictions of uses use such as poor toughness property. Blending PLA with other polymers is a more practical and economic way to improve its toughness. The present study assessed the effect of the addition of the pre-crosslinked powdered nitrile rubber (NBR) containing calcium carbonate (CaCO 3 ) and extruder screw rotation on the mechanical, rheological, morphological and thermal properties of polylactide (PLA) by using a Central Composite Rotatable Design (CCRD) analysis, which provides statistical support for the experimental data. The results showed that NBR/CaCO 3 can be used as toughness modifier for PLA. This property improved due to the increase in energy expended to deform the material and generate cracks, as showed in the impact and morphological analyzes. Despite this improvement, the presence of CaCO 3 caused a slight decline in the thermal resistance of the composites. The influence of rubber (NBR/CaCO 3 ) content in PLA matrix on rheological properties, such as elongation viscosity, melt strength and drawability was also investigated. The results showed that the composition PLA/NBR/CaCO 3 with higher NBR/CaCO 3 content can be used in thermoforming applications.