Fully biodegradable composites from poly (butylene succinate) modified with poly(3-hydroxybutyrate-co-4-hydroxybutyrate): fabrication and properties

Considering the current research background of environmental problems and shortages of petroleum resources aiming at proposing the “green” polymer blend with good degradability and properties similar to oil-based merchandise currently on the market, in the present study, two series of fully biodegradable blends consisting of PBS/P34HB (PBP) and PBS-g-GMA/P34HB (PGP) have been successfully fabricated by a simple and environmental-friendly processing methodology. In this work, the resulting biodegradable blends are in detail studied from the mechanical, thermal, crystallization, and morphology points of view. To improve the miscibility and enhance the interfacial adhesion between both phases of poly(butylene succinate) (PBS) as the matrix and poly (3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) as the modifier, with consequent improvement in material mechanical properties, glycidyl methacrylate (GMA) is grafted on PBS via reactive blending in the process. The incorporation of 10wt% P34HB into the blend promotes a dramatic increase of 614% in the Izod impact strength. The crystallization temperature (Tc) of PGP is 87.78℃ when 30wt% P34HB is added, which is 25% higher than that of pure PBS and 11% higher than that of the PBP blend. Meanwhile, the crystallinity of PGP is 30.12%, 47%, and 37% decline compared to pure PBS and PBP, respectively. Rheological results show that storage modulus, loss modulus, and complex viscosity improve significantly with the increase of P34HB amount, indicating that the enhancement of melt strength is beneficial to the processing and forming of the materials.