Polyhydroxybutyrate (PHB) is melt-processable semi-crystalline thermoplastic made by biological fermentation from renewable carbohydrate feedstocks. Although PHB homopolymer is a stiff and rather brittle polymer of high crystallinity, its mechanical properties are usually poor. The way of improvement of the mechanical properties is blending of PHB with a second degradable polymer, for instance with a random aliphatic-aromatic copolyester. The blends containing 5-20% of selected copolyester were prepared by using an internal mixer. Their mechanical properties were characterized by tensile test. Improvement of blends properties, when compared with pure PHB, was observed. The other properties of blends were characterized by the following techniques: differential scanning calorimetry (DSC), polarized light microscopy (PLM), X-ray scattering (WAXS, SAXS), thermogravimetry (TGA), scanning electron microscopy (SEM). It was shown that crystallization behaviour is different in comparison to pure PHB. The temperature of nonisothermal crystallization has shifted to lower values, but the cold crystallization has intensified. Acknowledgement Dr. Slawomir Dutkiewicz is acknowledged for copolyester preparation.
Properties of Polyhydroxybutyrate and its blends with copolyesters
Mariano Pracella
2012
Abstract
Polyhydroxybutyrate (PHB) is melt-processable semi-crystalline thermoplastic made by biological fermentation from renewable carbohydrate feedstocks. Although PHB homopolymer is a stiff and rather brittle polymer of high crystallinity, its mechanical properties are usually poor. The way of improvement of the mechanical properties is blending of PHB with a second degradable polymer, for instance with a random aliphatic-aromatic copolyester. The blends containing 5-20% of selected copolyester were prepared by using an internal mixer. Their mechanical properties were characterized by tensile test. Improvement of blends properties, when compared with pure PHB, was observed. The other properties of blends were characterized by the following techniques: differential scanning calorimetry (DSC), polarized light microscopy (PLM), X-ray scattering (WAXS, SAXS), thermogravimetry (TGA), scanning electron microscopy (SEM). It was shown that crystallization behaviour is different in comparison to pure PHB. The temperature of nonisothermal crystallization has shifted to lower values, but the cold crystallization has intensified. Acknowledgement Dr. Slawomir Dutkiewicz is acknowledged for copolyester preparation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
