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Purpose The objective of the present study was to better understand the potential environmental benefit of using vine shoots (ViShs), an agricultural residue, as filler in composite materials. For that purpose, a comparative life cycle assessment (LCA) of a rigid tray made of virgin poly(3-hydroxybutyrate-co-3-hydroxyvalerate) PHBV, polylactic acid (PLA) or polypropylene (PP), and increasing content of ViSh particles was performed. The contribution of each processing step in the life cycle on the different environmental impacts was identified and discussed. Furthermore, the balance between the environmental and the economic benefits of composite trays was discussed. Methods This work presents a cradle-to-grave LCA of composite rigid trays. Once collected in vineyards, ViShs were dried and ground using dry fractionation processes, then mixed with a polymer matrix by melt extrusion to produce compounds that were finally injected to obtain rigid trays for food packaging. The density of each component was taken into account in order to compare trays with the same volume. The maximum filler content was set to 30 vol% according to recommendations from literature and industrial data. The ReCiPe 2016 Midpoint Hierarchist (H) methodology was used for the assessment using the cutoff system model. Results and discussion This study showed that bioplastics are currently less eco-friendly than PP. This is in part due to the fact that LCA does not account for, in existing tools, effects of microplastic accumulation and that bioplastic technologies are still under development with low tonnage. This study also demonstrated the environmental interest of the development of biocomposites by the incorporation of ViSh particles. The minimal filler content of interest depended on the matrices and the impact categories. Concerning global warming, composite trays had less impact than virgin plastic trays from 5 vol% for PHBV or PLA and from 20 vol% for PP. Concerning PHBV, the only biodegradable polymer in natural conditions in this study, the price and the impact on global warming are reduced by 25% and 20% respectively when 30 vol% of ViSh are added. Conclusion The benefit of using vine shoots in composite materials from an environmental and economical point of view was demonstrated. As a recommendation, the polymer production step, which constitutes the most important impact, should be optimized and the maximum filler content in composite materials should be increased.

Durable goods last for years, decades, or even centuries. The environmental implications of the changing social, economic, and material conditions in which these goods are embedded can be overlooked by conventional life cycle assessment (LCA) that assumes a static world. To avoid this oversight, methods such as dynamic LCA (DLCA) are increasingly being used. Despite the growing use of DLCA, numerous questions remain, including how this dynamism is incorporated and what aspects of any given DLCA are dynamic. To answer these questions, we performed a review of 56 DLCAs, of which 44 propose a framework for DLCA covering all International Organization for Standardization phases of an LCA or that carry out a DLCA. Three types of LCA dynamism are identified and assessed for the reviewed literature: dynamic process inventory, dynamic systems, and dynamic characterization, while a further 2 types of LCA dynamism, dynamic scope and dynamic weighting, are proposed but not applied in the assessed literature. We found that the implementation of DLCA varies widely, and inventories accounting for dynamic characteristics are by far the most prevalent expression of DLCA. To reduce confusion surrounding the discussion of DLCA, we propose a definition of DLCA and its subtypes: full DLCA, partial DLCA, and prospective LCA. It is concluded that, among the current array of DLCA definitions, the implementation of partially dynamic LCA (PDLCA), which applies dynamism in only some parts of the LCA, is common and likely to continue. This is because PDLCA offers quantifiable marginal utility in terms of increased validity of the assessment, in relation to conventional LCA methods, but caution is needed in applying PDLCA because of potential for introducing bias into the LCA. To avoid this problem, we propose incorporating system dynamism as part of a sensitivity analysis, particularly in PDLCA that are limited by missing data. Integr Environ Assess Manag 2020;16:314-323. © 2019 SETAC

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