Effect of reprocessing cycles on the degradation of PP/PBAT-thermoplastic starch blends

Thainá A Oliveira; Rosimery R Oliveira; Renata Barbosa; Joyce B Azevedo; Tatianny S Alves

doi:10.1016/j.carbpol.2017.03.054

Effect of reprocessing cycles on the degradation of PP/PBAT-thermoplastic starch blends

Carbohydr Polym. 2017 Jul 15:168:52-60. doi: 10.1016/j.carbpol.2017.03.054. Epub 2017 Mar 19.

Authors

Thainá A Oliveira¹, Rosimery R Oliveira², Renata Barbosa³, Joyce B Azevedo⁴, Tatianny S Alves⁵

Affiliations

¹ Graduate Program in Materials Science, Technology Center, Federal University of Piauí, Teresina, PI 64049-550, Brazil. Electronic address: thaina-psique@hotmail.com.
² Graduate Program in Materials Engineering, Federal Institute of Education, Science and Technology of Piauí, Teresina, PI 64000-040, Brazil. Electronic address: rosimery_rodrigues@hotmail.com.
³ Course of Materials Engineering and Graduate Program in Materials Science, Technology Center, Federal University of Piauí, Teresina, PI 64049-550, Brazil. Electronic address: rrenatabarbosa@yahoo.com.
⁴ School of Technology SENAI CIMATEC, Salvador, BA 41650-010, Brazil. Electronic address: joycebazevedo@yahoo.com.br.
⁵ Course of Materials Engineering and Graduate Program in Materials Science, Technology Center, Federal University of Piauí, Teresina, PI 64049-550, Brazil. Electronic address: tsaeng3@yahoo.com.br.

PMID: 28457463
DOI: 10.1016/j.carbpol.2017.03.054

Abstract

The solid waste management problems caused by the accumulation of plastics require measures to mitigate the environmental damage, and mechanical recycling of plastics is among the possible solutions. In this context, the present study aimed to evaluate the effects of mechanical recycling on the properties of a polypropylene/poly(butylene adipate co-terephthalate)-thermoplastic starch blend (PP/PBAT-Thermoplastic starch blend) when it was subjected to seven reprocessing cycles by a single-screw extruder. The observations by infrared spectroscopy indicated that the chemical structures of the blend and the polypropylene matrix did not present significant changes with the reprocessing cycles. The X-ray diffraction analyses showed that the PP crystals were most affected when reprocessed in their pure form. The observations by thermogravimetry and differential scanning calorimetry indicated that the thermal stability of the blend was higher than that of polypropylene during the extrusion cycles. The scanning electron microscopy images indicated a weak interfacial interaction between the components of the blend, and the mechanical properties showed that the reprocessing improved the elasticity modulus and yield stress, with a consequential decrease of the impact strength.

Keywords: Degradation; PP/PBAT-Thermoplastic starch; Recycling.