Processing Biodegradable Blends of Hemicellulose with Polyhydroxybutyrate and Poly (Lactic Acid)

The bottleneck of hemicellulose as a bio-based material is its processability and property drawbacks (softening and hydrophilicity). Thus, mixing other biopolymers can be an alternative. This article proposes blending hemicellulose (10−50 wt%) with polyhydroxybutyrate (PHB) and poly (lactic acid) (PLA), using acetic acid and chloroform as casting solvents to improve its processability and thermal properties. The materials were thermally (TGA - thermogravimetric analysis), chemically (FTIR - Fourier transformer infrared) and morphologically (SEM - scanning electron microscopy) characterized. Finally, a multicriteria decision analysis (MCDA) evaluated the materials’ properties to identify the optimum combination (casting solvent, biopolymer and hemicelluloses proportion) for producing an optimal blend. The MCDA established that the blend of hemicellulose:PHB (10:90 wt/wt) produced with acetic acid was optimum considering melting temperature and the crystallinity criteria. Moreover, higher hemicellulose concentration in the blends decreased the MCDA success rate, indicating the worst properties. PLA blends showed a higher degradation temperature than PHB. The PHB blends produced with acetic acid demonstrated improved properties when compared to chloroform, revealing its potential as a solvent.

Keywords:
Hemicellulose; polyhydroxybutyrate; poly (lactic acid); blends; solvent casting; thermal properties