Microcapsules of Poly(butylene adipate-co-terephthalate) (PBAT) Loaded with Aliphatic Isocyanates for Adhesive Applications.

This work introduces the encapsulation of hexamethylene diisocyanate derivatives (HDI, TriHDI, and PHDI) with the biodegradable polymer poly(butylene adipate-co-terephthalate) (PBAT) through a solvent evaporation method. These microcapsules (MCs) were then employed in adhesive formulations for footwear. Moreover, MCs containing PHDI were produced in a closed vessel, demonstrating the potential for recovering and reusing organic solvents for the first time. The MCs were achieved with an isocyanate payload reaching up to 68 wt %, displaying a spherical shape, a core-shell structure, and thin walls without holes or cracks. The application of MCs as cross-linking agents for adhesives was evaluated following industry standards. The adhesives' strength surpassed the minimum requirement by a significant margin. Creep tests demonstrated that the formulation with MCs exhibits superior thermostability. Furthermore, the formulation with MCs-PHDI presented the best results reported to date for this type of system, as no displacement was observed in the bonded substrates. Environmental assessment indicates that adhesives with MCs have higher global warming potential (+16.2%) and energy consumption (+10.8%) than the standard commercial adhesives, but under alternative realistic scenarios, the differences can be insignificant. Therefore, adhesive formulations incorporating MCs promise to be on par with traditional adhesive systems regarding environmental impacts while providing benefits such as improved and safe handling of isocyanates and excellent bonding effectiveness.

Environmental and economic analysis of end of life management options for an HDPE product using a life cycle thinking approach.

Manufacturers have been increasingly considering the implication of materials used in commercial products and the management of such products at the end of their useful lives (as waste or as post-consumer secondary materials). The present work describes the application of the life cycle thinking approach to a plastic product, specifically an anti-glare lamellae (used for road safety applications) made with high-density polyethylene (HDPE). This study shows that optimal environmental and economic outcomes associated with this product can be realized by recovering the material at the end of its useful life (end of life, EoL) and by using the recycled HDPE as a raw material in the production of new similar products. The study confirmed the applicability of the life cycle thinking approach by industry in sustainable products development, supporting the development of robust environmental and economic guidelines.

Influence of the impact assessment method on the conclusions of a LCA study. Application to the case of a part made with virgin and recycled HDPE.

Recent legislation has stressed the need to decide the best end-of-life (EoL) option for post-consumer products considering their full life-cycle and the corresponding overall environmental impacts. The life cycle assessment (LCA) technique has become a common tool to evaluate those impacts. The present study aimed to contribute to the better understanding of the application of this technique, by evaluating the influence of the selection of the life cycle impact assessment (LCIA) method in its results and conclusions. A specific case study was chosen, using previous information related to an anti-glare lamellae (AGL) for highway use, made with virgin and recycled high-density polyethylene (HDPE). Five distinct LCIA methods were used: Eco-indicator 99, CML 2 (2000), EPS 2000, Eco-indicator 95 and EDIP 97. Consistent results between these methods were obtained for the Climate change, Ozone layer depletion, Acidification and Eutrophication environmental indicators. Conversely, the Summer smog indicator showed large discrepancies between impact assessment methods. The work sheds light on the advantages inherent in using various LCIA methods when doing the LCA study of a specific product, thus evidencing complementary analysis perspectives.

Life cycle assessment of a road safety product made with virgin and recycled HDPE.

The present study aims at evaluating the potential environmental impact of using recycled high-density polyethylene (HDPE) in the production of an anti-glare lamella (AGL), a road safety device currently manufactured from virgin (not recycled) polymer. The impact was evaluated using the life cycle assessment (LCA) technique and comparing two alternative systems: current AGL, manufactured from virgin HDPE, and optional AGL, made with recycled HDPE obtained from post-consumer packages. The AGL manufacturing phase was found to be responsible for most of the impacts in both systems, with the production of the raw material being the largest contributor for that phase. The present study makes a contribution to the problem of developing value-added products made from post-consumer polymeric recyclates.