Material Properties Synergistic effect of compatibilizer and sepiolite on the morphology of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/poly(butylene succinate) blends Amirouche Chikh a, b , Aida Benhamida b , Mustapha Kaci b , Isabelle Pillin a , St  ephane Bruzaud a, * a Institut de Recherche Dupuy de L^ ome (IRDL), FRE CNRS 3744, Universit e de Bretagne-Sud, Rue de Saint Maud e, 56321 Lorient Cedex, France b Laboratoire des Mat eriaux Polym eres Avanc es (LMPA), Universit e Abderrahmane Mira, Facult e de Technologie, Bejaia 06000, Algeria article info Article history: Received 11 April 2016 Accepted 10 May 2016 Available online 11 May 2016 Keywords: Poly(3-hydroxybutyrate-co-3- hydroxyvalerate) Poly(butylene succinate) Blends Compatibilization Morphology Properties abstract Blends of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(butylene succinate) (PBS) with different PHBV/PBS weight ratios (100/0, 75/25, 50/50 and 0/100) were elaborated by melt mixing. The morphological investigation of the different samples, in comparison with that of neat PHBV and neat PBS, pointed out that PHBV/PBS blends form a biphasic system over the whole composition range. Low amount of compatibilizing agent (5 wt%), obtained by grafting maleic anhydride (MA) onto PHBV, i.e. PHBV-g-MA, was used for improving the miscibility between the two components of the blend. The incorporation of a fibrous filler as the sepiolite, easily dispersible in a polymer matrix, was also inves- tigated. The morphology of the different blends as well as the evolution of their material properties were discussed in terms of the sepiolite and compatibilizing agent contents. The dispersion of PBS in the PHBV matrix markedly became finer with incorporation of sepiolite and PHBV-g-MA, due to enhanced in- teractions between the components. This paper highlighted a synergistic effect induced by the presence of both compatibilizer and sepiolite leading to an improved miscibility of the two blend components. The resulting properties were correlated with the morphology observed for the different blends. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction World consumption of polymers has increased exponentially since the last decades. Polymers are used in many areas, particu- larly in the packaging industry. Indeed, they have many advantages like light weight, low cost and processability. However, from a life cycle point of view, they also have several drawbacks. First, they are mainly based on non-renewable resources and their price is very dependent on oil prices. Then, polymer materials have a rather short period of use, especially in the packaging sector. The devel- opment of bio-based and biodegradable polymers appears as a promising alternative solution [1,2]. Among this class of polymers, polyhydroxyalkanoates (PHA), having thermoplastic and biodegradable properties, can constitute serious candidates to offer an alternative to polymers derived from petrochemicals [3]. PHA are versatile polyesters produced by numerous bacterial species as intracellular storage compounds of carbon and energy [4,5]. They have many other advantages like thermoplastic processing capacity, biodegradability and biocom- patibility [6,7]. However, for many applications, the properties of these PHA-based materials and their very high cost are inadequate for more developed industrial applications. To overcome this problem, there are different approaches. Among these, we can cite the development of new copolymers based on PHA [3,8,9] or the addition of micro- or nano-fillers in the PHA matrix [10e12]. However, the most convenient and less expensive method for developing PHA with improved properties remains the polymer blend [13,14]. In the PHA family, the most produced one is poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). However, its processability and brittleness limit its wide- spread applications [15]. Poly(butylene succinate) (PBS) which is a biodegradable synthetic polymer exhibiting excellent flexibility appears to be an interesting candidate in association with PHBV. PBS is usually synthesized via polycondensation of 1,4-butanediol with succinic acid, which can be derived from fossil-based or renewable resources [16,17]. PBS shows balanced mechanical * Corresponding author. E-mail address: stephane.bruzaud@univ-ubs.fr (S. Bruzaud). Contents lists available at ScienceDirect Polymer Testing journal homepage: www.elsevier.com/locate/polytest http://dx.doi.org/10.1016/j.polymertesting.2016.05.008 0142-9418/© 2016 Elsevier Ltd. All rights reserved. Polymer Testing 53 (2016) 19e28