Reactive extrusion of PLA, PBAT with a multi-functional epoxide: Physico-chemical and rheological properties Racha Al-Itry a,b , Khalid Lamnawar a,c , Abderrahim Maazouz a,b,d,⇑ a Université de Lyon, INSA-LYON, F-69361 Lyon, France b UMR 5223, Ingénierie des Matériaux Polymères IMP, CNRS, INSA Lyon, F-69621 Villeurbanne, France c UMR 5259, Laboratoire de Mécanique des Contacts et des Structures LaMCoS, CNRS, INSA Lyon, F69621 Villeurbanne, France d Hassan II Academy of Science and Technology, 10 100 Rabat, Morocco article info Article history: Received 28 November 2013 Received in revised form 14 March 2014 Accepted 19 June 2014 Available online 26 June 2014 Keywords: Reactive extrusion Chain extension Branching Linear rheology Thermo-rheological complexity Structural and solution viscometry abstract The aim of this work was to highlight the presence of long chain branching, LCB, due to the incorporation of a multifunctional epoxide, named Joncryl Ò , as a chain extender, into both poly (lactic acid) (PLA) and poly (butylene-adipate-co-terephtalate) (PBAT) polymers. The modified polymers were prepared using a twin-screw reactive extrusion system. It has been demonstrated through this study that these modified biopolymers are thermo- rheologically complex. This complexity may be attributed to the formation of covalent bonds between both polymer and chain extender and leads to a failure of the time- temperature superposition (TTS). The linear viscoelastic properties were predicated on the use of the so-called Van-Gurp–Palmen plots, from which the topology of the modified PLA and PBAT has been studied and analyzed. Indeed, they exhibited a typical feature of a mixture of linear and randomly branched polymers. Furthermore, the resulting linear and branched chains, due to the reactive highly functionalized epoxide, are discussed using rheological investigations (relaxation spectra, flow activation energy) coupled with solution viscometry (solution viscometry properties, hydrodynamic radius) and physico- chemical properties (size-exclusion chromatography). Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction Currently, most polymeric packaging materials are based on non-renewable fossil resources. Therefore, it is becoming more evident that ecosystems are disturbed con- sidering the net contribution of these petrochemical-based polymers to the increase of carbon dioxide emission. Hence, the importance of biodegradable polymers is continuing to grow. Significant attention has recently been paid to the poly (lactic acid) (PLA) since it is compostable and renewable, made by the fermentation of corn and sugar beets. PLA is linear aliphatic thermoplastic polyester. Extensive works related to PLA synthesis, chemical, physicochemical and mechanical properties have been performed. A comparison of mechanical properties among other common polymers shows that PLA is much like polystyrene; it has relatively high modulus but is brittle. Another potential problem with PLA is that it has a lower melt strength compared to conventional polymers limiting its use in wide range of applications dedicated to blown extrusion for example [1–3]. To improve mechanical properties and processability of PLA and retain its biodegradability, blending PLA with other biodegradable polymer is used. Biodegradable polyesters generally work well in blends with PLA, starch, and natural fiber reinforcements. A broad range of http://dx.doi.org/10.1016/j.eurpolymj.2014.06.013 0014-3057/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Université de Lyon, INSA-LYON, F-69361 Lyon, France. Tel.: +33 472 43 63 32; fax: +33 472 438 5 15. E-mail address: abderrahim.maazouz@insa-lyon.fr (A. Maazouz). European Polymer Journal 58 (2014) 90–102 Contents lists available at ScienceDirect European Polymer Journal journal homepage: www.elsevier.com/locate/europolj