Search

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is among the most attracting low environmental impact polymeric materials. Coffee Silverskin (CS), an agro-food residue, has been compounded in variable amounts into a PHBV matrix in the presence of acetyl tributyl citrate (ATBC) as plasticizer, and calcium carbonate (CaCO3) as filler, to produce biocomposites through a pre-industrial scale melt extrusion technique. Thermal, morphological and mechanical properties have been investigated in order to validate whether these PHBV/CS based biocomposites could be used to manufacture moulded items, e.g. coffee capsules body. The increasing concentration of CS in PHBV improves the stiffness and the heat deflection temperature properties of the biocomposites. Coffee capsules body have been produced by injection moulding starting from the optimized formulations, based on the PHBV/CS system, and were characterized in terms of migration properties in contact with simulants. Notably, the overall migration at 100 °C was below the limit (10 mg/dm²) required for plastic materials in food contact applications. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) is a compostable and sustainable polymer, derived from renewable resources, with high elastic modulus and high transparency. By the way PLA has even some limitations such as low glass transition temperature, low thermal stability, high brittleness, and low crystallization rate. To increase flexibility of PLA based materials it is possible to add low molecular weight plasticizers or prepare blends with another flexible polymer, such as poly(butylene adipate-co-terephthalate) (PBAT). Even the use of a compatibilizer may allow a modulation of mechanical properties thanks to the achievement of a phase morphology characterized by a lower dimension of the dispersed PBAT phase and an increased adhesion. In the present study, blends of PLA and PBAT were prepared by adding different plasticizers combinations based on an oligomer of lactic acid, a polyester of adipic acid and 1,2-propane diol, and an epoxy functionalised resin. All the plasticizers were effective in providing flexibility to the blends, with higher efficiency from the epoxy functionalised plasticizer, and the polyester of adipic acid. Fox’s equation showed that all plasticizers have the tendency to disperse more in the amorphous PBAT matrix than in the PLA one. [ABSTRACT FROM AUTHOR]

The addition of rejuvenators agents (RJ) into bitumen allows increasing the amount of recycled asphalt in new mixtures. In the preliminary part of this study, three different type of oils were tested as potentials RJ: a mineral oil from the automotive industry, a waste domestic cooking vegetable oil (VO), and a biodiesel. Several mixtures were prepared by adding different percentage of oils and VO was individuated as the best RJ. Therefore, VO was used in a further investigation, to better characterize the properties of the rejuvenated binder and its resistance to aging during a second life cycle. Rejuvenated binders with different oil content were prepared and evaluated. The rheological characterization included frequency sweep tests to obtain the binder master curves and linear amplitude sweep test to evaluate the cumulative damage resistance. Moreover, the molecular weight distributions of the binders were investigated by both gel permeation chromatography and rheology by application of the delta-method. [ABSTRACT FROM AUTHOR]

Poly(lactic acid)/triacetine plasticized cellulose acetate (PLA/pCA) blends were prepared by extrusion at two different temperatures and tetrabutylammonium tetraphenyl borate (TBATPB) was added as a transesterification catalyst to reactively promote the formation of PLA-CA copolymer during the reactive extrusion. The occurrence of chain scission in the PLA phase and branching/crosslinking in the CA phase in the presence of TBATPB, resulting also in a darkening of the material, were demonstrated by studying torque measurements and by performing proper thermogravimetric tests on CA with the different additives. Tensile and impact tests onto the blends prepared at the lower temperature showed better properties than the ones obtained at a higher temperature. Then, the mechanical properties of PLA/plasticized cellulose acetate (pCA) blends prepared at the lower temperature were investigated as a function of the content of plasticized CA in the blend. A range of compositions was observed where blends exhibited improved impact properties with respect to pure PLA without a significant decrease in their elastic modulus. The study of the phase morphology of the blends revealed that the occurrence of reactive compatibilization did not significantly affect the phase distribution. In general, fibrillar CA particles were formed in the PLA matrix during extrusion, thus allowing the preparation of CA fibre reinforced composites. The trend of morphology as a function of the composition and processing conditions was then discussed by considering the evolution of phase morphology in immiscible polymer blends. [ABSTRACT FROM AUTHOR]