ORIGINAL PAPER Role of bacterial cellulose and poly (3-hydroxyhexanoate-co- 3-hydroxyoctanoate) in poly (3-hydroxybutyrate) blends and composites Denis Mihaela Panaitescu . Adriana Nicoleta Frone . Ioana Chiulan . Cristian Andi Nicolae . Roxana Trusca . Marius Ghiurea . Augusta Raluca Gabor . Mona Mihailescu . Angela Casarica . Irina Lupescu Received: 16 April 2018 / Accepted: 5 August 2018 Ó Springer Nature B.V. 2018 Abstract Biodegradable and biocompatible poly (3- hydroxybutyrate) (PHB) is considered a good candi- date for biomedical applications provided that its inherent brittleness and thermal stability are corrected. In this work, poly (3-hydroxyhexanoate-co-3-hydrox- yoctanoate) (PHHO) and bacterial cellulose nanofi- bers (BC) were used as ‘‘soft’’ and ‘‘stiff’’ modifiers to improve PHB properties. PHHO (5–20 wt%) increased the thermal stability of PHB and PHB-BC composites. On the other hand, BC increased the glass transition and the crystallization temperature of PHB in the blends. The surface morphology of PHB was differently changed by the addition of PHHO and BC: a microporous surface morphology with many well spread pores was produced by the addition of PHHO (20–50 wt%) and a smoother surface by the addition of BC. Still, the surface morphology of PHB/PHHO blends, with homogenously spread submicronic pores, was not changed by BC. Thermal, structural and morphological investigations showed that BC nanofi- bers are mainly located in PHHO rich phase and at interface. PHB nanocomposite with 20 wt% PHHO showed balanced stiffness-toughness properties and excellent thermal stability, with the onset thermal Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10570-018-1980-3) con- tains supplementary material, which is available to authorized users. D. M. Panaitescu (&) Á A. N. Frone Á I. Chiulan Á C. A. Nicolae Á M. Ghiurea Á A. R. Gabor Polymer Department, National Institute for Research & Development in Chemistry and Petrochemistry - ICECHIM, 202 Splaiul Independentei, Sector 6, 060021 Bucharest, Romania e-mail: panaitescu@icechim.ro R. Trusca Science and Engineering of Oxide Materials and Nanomaterials, University Politehnica of Bucharest, 1-7 Gh. Polizu Street, 011061 Bucharest, Romania M. Mihailescu Physics Department, Faculty of Applied Sciences, Politehnica University of Bucharest, 313 Spl. Independentei, 060042 Bucharest, Romania A. Casarica Á I. Lupescu National Institute for Chemical Pharmaceutical Research and Development ICCF, 112 Calea Vitan, 031299 Bucharest, Romania I. Lupescu Department of Veterinary Medicine, Spiru Haret University, 256 Basarabia Blvd, 030352 Bucharest, Romania 123 Cellulose https://doi.org/10.1007/s10570-018-1980-3