Biobased poly(butylene 2,5-furandicarboxylate) and poly(butylene adipate-co-butylene 2,5-furandicarboxylate)s: From synthesis using highly purified 2,5-furandicarboxylic acid to thermo-mechanical properties Binshuang Wu a , Yutao Xu a , Zhiyang Bu a , Linbo Wu a, * , Bo-Geng Li a , Philippe Dubois b a State Key Laboratory of Chemical Engineering at ZJU, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China b Laboratory of Polymeric and Composite Materials (LPCM), Center of Innovation and Research in Materials and Polymers (CIRMAP), University of Mons, Mons 7000, Belgium article info Article history: Received 9 April 2014 Received in revised form 31 May 2014 Accepted 14 June 2014 Available online 24 June 2014 Keywords: Biobased polymers Biodegradable polymers Aliphatic-aromatic copolyesters abstract To synthesize high quality (co)polyesters derived from 2,5-furandicarboxylic acid (FA), an acetic acid refluxing/pH-swing method was proposed to purify FA. 2-Carboxyl furfural and other impurities were removed completely from FA with this method. Using highly purified FA, biobased polyester poly(- butylene furnadicarboxylate) (PBF) and aliphatic-aromatic copolyesters poly(butylene adipate-co- butylene 2,5-furandicarboxy-late)s (PBAFs) were synthesized via melt (co)polycondensation. The (co) polyesters were characterized with GPC, FTIR, 1 H NMR, DSC and TGA, and their tensile mechanical properties were also assessed. The copolyesters possess random chain structure, monomer feed ratio- controlled copolymer composition and excellent thermal stability (T d,5% > 340  C) in full composition range. Both BA-rich and BF-rich PBAFs are crystalline polymers. The crystallizability decreases with composition, up to nearly amorphous at moderate f BF (40e60%). PBAFs with f BF no more than 50% exhibit obvious high-elastic deformation and rebound resilience, and possess tensile properties (E 18 e160 MPa, s b 9e17 MPa, ε b 370e910%) comparable to poly(butylene adipate). PBAFs with higher f BF behave like nonrigid plastics with low tensile moduli (42e110 MPa), moderate strength (30e42 MPa) and high elongation at break (310e470%). In comparison, PBF is a strong and tough thermoplastic having balanced mechanical properties, namely, much higher tensile modulus (1.9 GPa) and strength (56 MPa) and high elongation at break (260%). It seems necessary and effective to use highly purified FA for synthesizing high performance FA-derived (co)polyesters. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction As replacement of polymers derived from fossil resources, polymers based on bio-renewable resources have drawn world- wide attention from both academia and industry due to the sus- tained dwindling of fossil resources as well as increasing environmental concerns [1e6]. The burgeoning surge in conversion and utilization of biomass in recent years has offer great opportu- nities in synthesizing biobased monomers and polymers [2e6]. 2,5- furandicarboxylic acid (FA) is an important biobased monomer, which can be produced in large scale from cellulose or hemi- cellulose via a multistep process including bioconversion, dehydration and oxidation [7e10]. Because of its aromatic structure and biobased origin, FA has been highlighted as potential replace- ment of fossil-based monomers like terephthalic acid (TPA). It has also been screened to be one of the most important biobased building blocks by the U.S. Department of Energy [11]. Therefore FA represents a very promising monomer for new biobased polyesters and other polymers. In recent years, FA-based polyesters including poly(ethylene furandicarboxylate) (PEF) [12e16], poly(propylene furandicarbox- ylate) (PPF) [13,15], poly(butylene furandicarboxylate) (PBF) [15e17]and others [17e19] have been reported. These polyesters are deemed as furan counterparts of TPA-based polyesters because they display comparable thermo-mechanical properties. Several aro- matic copolyesters derived from FA have also been reported [20,21]. All these aromatic (co)polyesters, like the TPA counterparts, will not be biodegradable. However, aliphatic-aromatic copolyesters of FA, * Corresponding author. Tel.: þ86 571 87952631; fax: þ86 571 87951612. E-mail addresses: wulinbo@zju.edu.cn, wulinbohz@gmail.com (L. Wu). Contents lists available at ScienceDirect Polymer journal homepage: www.elsevier.com/locate/polymer http://dx.doi.org/10.1016/j.polymer.2014.06.052 0032-3861/© 2014 Elsevier Ltd. All rights reserved. Polymer 55 (2014) 3648e3655