Publicação
Assessment of recycled polypropylene–biomass composites for buildings indoors and outdoors application
| Resumo: | This study evaluates the durability of biocomposites formulated from recycled polypropylene (PP) from used coffee capsules, in comparison to virgin PP, incorporating three different micronized biomasses – olive pit, hemp bast fibre and wood chips – for potential indoor (e.g. floorboards and skirting boards) and outdoor (e.g. ventilated façade cladding and decks) building applications. The latter is considered as reference, as it has been studied in literature, together with control specimens with no biomass. Specimens were subjected to natural weathering for 120 days, and their properties were compared with those of non-weathered specimens, simulating requirements for both outdoor and indoor building products. The weathering of wood-plastic composites has been extensively studied in the literature, but not so much the one of other biomass-plastic composites. The results demonstrate that incorporating biomass slightly improves certain mechanical properties, particularly surface hardness by 1–4 %, and reduces thermal dimension variation by 15–60 %, depending on the type of biomass. However, it generally reduces tensile strength by 10–50 % and increases water absorption by up to 236 %, depending on the biomass and matrix used. Biocomposites have showed a significant colour change, becoming considerably lighter, when exposed to weathering. The use of recycled PP, which is darker than virgin PP, contributed to improved resistance against UV degradation. Superior mechanical performance was obtained by the PPr-wood biocomposite, while the olive pit biocomposites evidenced an exceptional colour stability and lower susceptibility to biological colonisation. This research supports the potential application of recycled PP-based biocomposites in indoor and outdoor environments, while also highlighting the trade-offs between environmental benefits and performance characteristics. Improving PP coffee capsules recycling to avoid metal residues is mandatory and justifies future pilot-scale validation. |
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| Autores principais: | Duarte, Alexandre |
| Outros Autores: | Faria, Paulina; Pires, João; Baltazar, Luis G. |
| Assunto: | Biocomposite Durability Hemp fibre Olive pit Plastic from waste coffee capsules Weathering Wood chips Civil and Structural Engineering Building and Construction General Materials Science |
| Ano: | 2026 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso embargado |
| Instituição associada: | Universidade Nova de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório Institucional da UNL |
| Resumo: | This study evaluates the durability of biocomposites formulated from recycled polypropylene (PP) from used coffee capsules, in comparison to virgin PP, incorporating three different micronized biomasses – olive pit, hemp bast fibre and wood chips – for potential indoor (e.g. floorboards and skirting boards) and outdoor (e.g. ventilated façade cladding and decks) building applications. The latter is considered as reference, as it has been studied in literature, together with control specimens with no biomass. Specimens were subjected to natural weathering for 120 days, and their properties were compared with those of non-weathered specimens, simulating requirements for both outdoor and indoor building products. The weathering of wood-plastic composites has been extensively studied in the literature, but not so much the one of other biomass-plastic composites. The results demonstrate that incorporating biomass slightly improves certain mechanical properties, particularly surface hardness by 1–4 %, and reduces thermal dimension variation by 15–60 %, depending on the type of biomass. However, it generally reduces tensile strength by 10–50 % and increases water absorption by up to 236 %, depending on the biomass and matrix used. Biocomposites have showed a significant colour change, becoming considerably lighter, when exposed to weathering. The use of recycled PP, which is darker than virgin PP, contributed to improved resistance against UV degradation. Superior mechanical performance was obtained by the PPr-wood biocomposite, while the olive pit biocomposites evidenced an exceptional colour stability and lower susceptibility to biological colonisation. This research supports the potential application of recycled PP-based biocomposites in indoor and outdoor environments, while also highlighting the trade-offs between environmental benefits and performance characteristics. Improving PP coffee capsules recycling to avoid metal residues is mandatory and justifies future pilot-scale validation. |
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