Effect of the Molecular Structure of Poly(3-hydroxybutyrate-<i>co</i>-3-hydroxyvalerate) (P(3HB-3HV)) Produced from Mixed Bacterial Cultures on Its Crystallization and Mechanical Properties
Julie Bossu, Hélène Angellier‐Coussy, Cédric Totée, Mariana Matos, Maria A.M. Reis, Valérie Guillard
Abstract
High Resolution Image Download MS PowerPoint Slide Poly(3-hydroxybutyrate- co -3-hydroxyvalerate) (P(3HB-3HV)) copolymer’s properties depend on (i) the molar fraction of comonomers, (ii) the overall molar mass, and (ii) the chemical compositional distribution. This work aims at providing a better understanding of the effect of the P(3HB-3HV) molecular structure, produced from mixed cultures and waste feedstock, on copolymer crystallization and tensile properties. Conventional biopolymer characterization methods (differential scanning calorimetry, X-ray diffraction, and polarized optical microscopy) were coupled to both classical one-dimensional ( 1 H and 13 C) and advanced two-dimensional (diffusion-ordered spectroscopy (DOSY) and 1 H/ 13 C heteronuclear single quantum coherence (HSQC)) nuclear magnetic resonance (NMR) spectroscopy techniques. The obtained results evidenced that (i) a high-quality copolymer could be achieved, even from a waste feedstock; (ii) increasing the 3HV content displayed a positive impact on P(3HB-3HV) mechanical properties only if good interactions between 3HB and 3HV moieties were established; and (iii) the purification process eliminated short-length 3HV-rich chains and promoted homogeneous co-crystallization. Such optimized microstructures enabled the maximal stress and strain at break to be increased by +41.2 and +100%, respectively.