The widespread use of poly(lactic acid) (PLA) from packaging to engineering applications seems to follow the current global trend. The development of high-performance PLA-based blends has led to the commercial introduction of various PLA-based resins with excellent thermomechanical properties. The reason for this is the progress in the field of major PLA limitations such as low thermal resistance and poor impact strength. The main purpose of using biobased polymers in polymer blends is to increase the share of renewable raw materials in the final product rather than its possible biodegradation. However, in the case of engineering applications, the focus is on achieving the required properties rather than maximizing the percentage of biopolymer. The presented review article discusses the current strategies to optimize the balance of the key features such as stiffness, toughness, and heat resistance of PLA-based blends. Improving of these properties requires molecular structural changes, which together with morphology, crystallinity, and the influence of the processing conditions are the main subjects of this article. The latest research in this field clearly indicates the high potential of using PLA-based materials in highly demanding applications. In the case of impact strength modification, it is possible to obtain values close to 800 J/m, which is a value comparable to polycarbonate. Significant improvement can also be confirmed for thermal resistance results, where heat deflection temperatures for selected types of PLA blends can reach even 130 °C after modification. The modification strategies discussed in this article confirm that a properly conducted process of selecting the blend components and the conditions of the processing technique allows for revealing the potential of PLA as an engineering plastic.

The details of the electronic band structure of GaSbBi as functions of Bi mole fraction and along different symmetry directions of the crystal are calculated using a 14 band k.p model considering the band anti-crossing interaction between the valence band of the host III-V material and the Bi related impurity level resonant with the host. The effect of the lattice strain on the band structure as a result of incorporating a higher amount of Bi in the material is also studied. Variations of the bandgap energy, spin orbit split-off energy, band offsets, and the different sub-band energies are presented as functions of Bi content in GaSbBi as well as along the three symmetric k directions. Effective mass of the charge carriers and their dependence on Bi content is investigated. Furthermore, the intrinsic carrier concentration of the material as a function of Bi composition is evaluated. Finally, the optical absorption in the material is investigated considering the electronic transitions involving various valence sub bands and the conduction band.

We have investigated the influence of Pb vs Ga solvents during the liquid phase epitaxial growth of GaSbBi layers on the overall physical, optical, and electrical properties of the material. 10 K photoluminescence (PL) measurements show narrower PL linewidths in layers grown from the Pb solvent compared to that obtained for layers grown under similar conditions using Ga as the solvent. This is an indication of the improved crystalline quality of the material grown from the Pb solvent. GaSbBi layers grown from Pb solvents show a reduction of the carrier concentration by over one order of magnitude than that measured in the corresponding materials grown from Ga solvents. Detailed analysis of the core level transitions, revealed by X-ray photoelectron spectroscopy, indicates the generation of a lesser number of V_Ga and antisite Ga_Sb defects responsible for the residual hole concentration in GaSb and GaSbBi layers grown from Pb solvents than in the same materials grown using Ga as the solvent. This is suggested as the main reason for the observed reduction of carrier concentration in the layers grown from the Pb solvent.