Global concerns over environmental issues have led to a tremendous growth in sustainable materials emerging from biobased plastics and their composites (biocomposites). This class of materials can be an alternative to traditional composite materials to reduce the carbon footprint and strain on the environment. Many studies and reviews have been focused on enhancing the mechanical performance of biocomposites with the aim for them to compete with traditional composites and expand their applications. However, the current scientific knowledge relating to the long-term durability performance of biocomposites is very limited in open access literature. Studies of the effects of different aging mechanisms when subjected to different service conditions and environments on the biocomposites' behaviours are needed. This review provides a focused discussion on the overview of the long-term durability performance and degradation behaviour under various aging environments (thermo-oxidative aging, accelerated weathering (ultraviolet aging), hydrolytic degradation, fatigue and creep, etc.) of the commercially important biobased-composites for the first time. Future perspectives and methods to improve the durability performance of biocomposites are also discussed in this review.

Ending the fossil fuel era towards a sustainable future will require high-performing renewable materials with a low environmental impact. Carbon black, produced by partial combustion or thermal decomposition of petroleum hydrocarbons, is by far the most dominant filler of rubber composites, followed by mineral fillers (e.g. silica, talc, clay, calcium carbonate, etc.). However, the manufacture of carbon black has a considerable carbon footprint. Similarly, mineral fillers also do not come without challenges, including poor compatibility with rubber matrices and high density. Consequently, the need for sustainable and green fillers with a low or even zero carbon footprint has dramatically increased. In recent years, plant-derived sustainable materials, such as cellulose nanocrystals, natural fibers, lignin, biochar, polysaccharides, etc., have been extensively investigated as substitute or complementary fillers of rubbers. In this work, we critically reviewed recent developments in the innovation and utilization of sustainable biofillers for rubber composite applications, emphasizing the effect of the filler on the structure–processing–property relationships in rubber composites. A wide range of biofillers with an array of structure, morphology, and physico-chemical properties and their various attributes in different rubbers are intensively reviewed and discussed. Effective preparation strategies and surface modification platforms on the different biofillers to develop high-performance sustainable rubber biocomposites were critically reviewed. Finally, future perspectives for biofillers in rubber composite applications and challenges are discussed.

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.