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Biobased and biocompatible polymers, such as polyhydroxyalkanoates (PHAs), are of great interest for a large range of applications in the spirit of green chemistry and upcoming reuse and recycling strategies. Polyhydroxybutyrate (PHB), as a promising biocompatible polymer belonging to PHAs, is subject to increased research concern regarding the high degree of crystallinity and brittle behavior of the resulting materials. Therefore, the improvement of PHB's physico-mechanical properties aims to decrease the Young's modulus values and to increase the ductility of samples. Here, we proposed an ambitious approach to develop melt-processed materials, while combining PHB characteristics with the ductile properties of poly(ε-caprolactone) (PCL). In order to compatibilize the poorly miscible PHB/PCL blends, dicumyl peroxide (DCP) was used as a free-radical promotor of polyester interchain reactions via the reaction extrusion process. The resulting PHB/PCL-DCP materials revealed a slight increase in the elongation at break, and significant improvement in the impact resistance (7.2 kJ.m−2) as compared to PHB. Additional decrease in the Young's modulus values was achieved by incorporating low molecular polyethylene glycol (PEG) as a plasticizer, leading to an important improvement in the impact resistance (15 kJ.m−2). Successful 3D printing using fused deposition melting (FDM) of the resulting PHB/PCL-based blends for the design of a prosthetic finger demonstrated the great potential of the proposed approach for the development of next-generation biomaterials. [ABSTRACT FROM AUTHOR]

Vulcanized and devulcanized ground tire rubber microparticles have been used as a minor phase in acrylonitrile butadiene styrene copolymer (ABS) and thermoplastic polyolefins (TPO) for the development of materials with desired functionalities by 3D printing. These polymers have been selected because they (i) present part of the plastic waste generated by the automotive industry and (ii) have totally different properties (ABS for its stiffness and robustness and TPO for its softness and ductility). The study aims to improve the circular economy of the automotive industry by proposing a promising route for recycling the generated tire rubber waste. In this respect, emergent technology for plastic processing such as 3D printing is used, as part of the additive manufacturing technologies for the prolongated end of life of recycled plastics originated from automotive waste such as ABS and TPO. The obtained results revealed that (i) the composites are suitable for successful filament production with desired composition and diameter required for successful 3D printing by fused deposition modeling, and that (ii) the optimization of the composition of the blends allows the production of materials with interesting mechanical performances. Indeed, some of the investigated ABS-recycled rubber tire blends exhibit high impact properties as TPO-based composites do, which in addition exhibits elongation at break higher than 500% and good compression properties, accompanied with good shape recovery ratio after compression. [ABSTRACT FROM AUTHOR]