The increased awareness of the environmental effects of petroleum based plastics has stimulated the coffee price emergence of biodegradable polymers such as polylactic acid (PLA). In a bid to increase the sustainability of PLA agricultural residues of animal feeds (corn stover, rice straw, and soybean hulls) have been explored and examined as reinforcing fillers to PLA composites. The consideration of such applications is suitable to the goals of the circular economy as it recycles low-value agricultural products. The current review critically evaluates lately carried out life cycle assessment (LCA) studies on PLA composites that have implemented such waste fillers with the full focus being on their environmental performance as well as methodological consistency. The review shows that these fillers have a potential of reducing the amount of greenhouse emission, energy usage, and other environmental effects, compared to pure PLA. However, unevenness in LCA methodology, especially in functional units, the system boundaries, and impacts categories obstructs direct LCA comparisons. The 1997 State of the Market report also has limited options of feedstocks and the lack of appraisals in the socio-economic front, so the overall sustainability analysis is restricted. Some of the remaining limitations that can be critical are to have generalized LCA frameworks, extended exploration of waste-based fillers, as well as combination of techno-economic analysis and social impact. Future inquiries ought to devise design considerations that would optimize both the functional characteristics and the performance of the environment and improve the reliability of sustainability measures. This review is evidence to the potential of agricultural waste reinforced PLA composites in the progress towards environmentally friendly materials and the need of integrative evaluation in the sustainable maturation of bioplastics.

The low V-notch impact toughness is a notable limitation of the PBT/PA6 blend. In this study, we maintained a fixed PBT/PA6 ratio of 50/50 while varying the proportion of PP in the given blend at levels of 0%, 70%, 80%, 90%, and 100% neat PP. The results from the unnotched impact toughness tests for the PP/PBT/PA6 blends showed favorable outcomes. Specifically, the impact toughness of the PP/PBT/PA6 samples progressively increased with the rise in PP content. Initially, the toughness dropped from 10.13 kJ/m² in the 0% PP sample to 8.6 kJ/m² in the 70% PP sample, before increasing gradually from 8.6 kJ/m² in the 70% PP sample to 17.45 kJ/m² in the 90% PP sample to 17.45 kJ/m² in the 90% PP sample, which represents an increase of about 72% relative to the 0% PP sample. These positive results demonstrate that the addition of PP significantly enhances the impact toughness of the blend compared to formulations without PP.