Rheological characteristics PBAT/organoclay compounds

Tiago T Santos ,Pankaj Agrawal,Camila Ariana Becker Pereira,Eduardo L Canedo ,Tatiara G Almeida ,Laura H Carvalho

doi:10.1590/0370-44672018720077

Tiago T Santos , Pankaj Agrawal + Show 4 more

Open Access

https://doi.org/10.1590/0370-44672018720077

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Abstract

Abstract The rheological behavior of poly (butylene adipate-co-terephthalate) (PBAT) and its composites prepared with three different organoclays was investigated. Composites containing up to 7.5%, w/w organoclay, were prepared by two routes: (a) direct melt blending in an internal laboratory mixer with high intensity rotors and (b) concentrates (prepared in the internal mixer) with 50 %, by weight, of the organoclays diluted in a co-rotating twin screw extruder equipped with a high intensity mixing thread operating at a nominal speed of 480 rpm. The samples were characterized by both torque and parallel plate rheometry. Results indicate that nanodispersions in the clay layers were obtained during processing and that, like the pure matrix, at high shear rates, the organoclay compounds follow the power law, although with higher viscosity. It is believed that the interaction of the polymer with the organoclay is responsible for the increase in melt viscosity (observed by increases in torque and relaxation time) of the hybrid systems.

Highlights

Nowadays there is a growing interest in moving towards the production of polymer materials and/or blends that are more environmentally friendly than most commercial polymers, such as polyethylene, polypropylene and polystyrene are not biodegradable and their disposal leads to severe environmental problems (Kashi et al, 2016)
Samples of Poly(butylene adipate-co-terephthalate) (PBAT), as well as processed PBAT and PBAT/5%Cloisite 10A (C10A), PBAT/5%Cloisite 20A (C20A), and PBAT/5%Cloisite 30b (C30B) compounds prepared as described in the Experimental section, were tested by parallel plate rheometry at three temperatures (170°C, 180°C and 190°C) and frequencies in the range 0.012 to 600 s-1
The rheological behavior of the matrix and the prepared nanocomposites were investigated by torque rheometry and a parallel plate rheometry to understand the effects of the interaction between matrix and organoclays on the rheological behavior of these materials

Summary

Introduction

Nowadays there is a growing interest in moving towards the production of polymer materials and/or blends that are more environmentally friendly than most commercial polymers, such as polyethylene, polypropylene and polystyrene are not biodegradable and their disposal leads to severe environmental problems (Kashi et al, 2016). It is deemed to be completely biodegradable with the aliphatic part being responsible for its biodegradability, and the aromatic part providing good mechanical properties compared to other polymers (Bittmann et al, 2012, Shalari and Lee, 2012). It displays good adhesion and compatibility with many other polymers (Yeh et al, 2010). While exhibiting some excellent properties, such as greater elongation at break and thermal stability at elevated temperatures than most biodegradable polyesters, PBAT has low tensile strength and is often used as a second phase in polymer blends. Some researchers have shown that the addition of inorganic fillers, such as clays, to PBAT can improve this low resistance, generating systems with improved mechanical, thermal and electrical properties (Fukushima et al, 2013, Wu, 2009)

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