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This paper describes a study on the use of a polypropylene (PP)/layered silicate nanocomposite as packaging film, agricultural film, and automotive panels. The study's main question was ''Are the environmental impacts and costs throughout the life cycle of nanocomposite products lower than those of products manufactured from conventional materials?'' The conventional (benchmark) materials studied were pure polypropylene as packaging film, pure polyethylene as agricultural film, and glass fiber-reinforced polypropylene as automotive panels. In all three cases, the use of the PP nanocomposite resulted in a reduction of the amount of material used, while ensuring the same functionality. Material reduction was estimated using Ashby's material indices and amounted to À9% for packaging film, À36.5% for agricultural film, and À1.25% for automotive panels. It goes without saying that a product's impact on the environment will decrease when less material is used. The production and incorporation of nanoparticles, however, may have additional impacts. We found clear environmental benefits throughout the entire life cycle when the PP nanocomposite is used in the manufacture of agricultural film. We noted some cost benefits when the nanocomposite is used in the production of agricultural film and automotive panels. If the price of nanoclay is at most €5,000 tonne then the cost of nanocomposite packaging film is also lower than that of the conventionally produced product.

Purpose The demand of PET bottles has increased rapidly in the past decades. The purpose of this study is to understand the environmental impact of PET recycling system, in which used bottles are recycled into both fibre and bottles, and to compare the recycling system with single-use PET. Methods Consequential LCA modelling was applied to understand four change-oriented effects for the recycling system. These include the effect of multiple-recycling trips, the effect of changing the share of recycled PET pellets used to make bottles or fibre, the effect of changing the reference system and the effect of introducing bio-based PET. The functional unit of the baseline case was determined as 350 kg of bottles and 650 kg of fibre based on the current market demand of PET. The system boundary is cradle to grave excluding the use phase. We applied the "system expansion" method to open-loop recycling. The analysis compares the baseline recycling system, where PET is recycled once, with the reference system, where PET is not recycled. The environmental impacts assessed are non-renewable energy use and global warming.Results and discussion The baseline recycling system reduces both impacts by 20% when compared to the reference system. Multiple-recycling trips can maximally reduce the impacts by 26% but the additional savings are negligible after three recycling trips. Bottle-to-fibre recycling offers more impact reduction than bottle-tobottle recycling when more fibre is needed than bottles in a functional unit. The maximal impact reduction of 25% can be achieved when all recycled PET pellets are used to make fibre. If the functional unit is reversed, i.e. changed to 650 kg of bottles and 350 kg of fibre, 30% of the impact reduction can be achieved. Both impacts can be further reduced when the quantity of the recycled PET is maximised. The bio-based PET recycling system, offers at least 36% impact reduction, has the lowest impact among all systems studied. The sensitivity analyses show that the recycled PET content in a recycled bottle is not influential to the overall environmental performance. Conclusions All PET recycling systems in this study show important impact reduction compared to the reference system. The impact savings are around 20-30% depends on the configurations of the recycling system. We conclude that the system's environmental impact can be optimised by maximising the amount of recycled PET in the system and by using bio-based polymers.

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The goal of our study was to investigate the potential benefits of reinforcing polymer matrices with nanoobjects for structural applications by looking at both the mechanical properties and environmental impacts. For determining the mechanical properties, we applied the material indices defined by Ashby for stiffness and strength. For the calculation of environmental impacts, we applied the life cycle assessment methodology, focusing on nonrenewable energy use (NREU). NREU has shown to be a good indicator also for other environmental impacts. We then divided the NREU by the appropriate Ashby index to obtain the 'functionality-based NREU'. We studied 23 different nanocomposites, based on thermoplastic and thermosetting polymer matrices and organophilic montmorillonite, silica, carbon nanotubes (single-walled and multiwalled) and calcium carbonate as filler. For 17 of these, we saw a decrease of the functionality-based NREU with increasing filler content. We draw the conclusion that the use of nanoobjects as filler can have benefits from both an environmental point of view and with respect to mechanical properties.

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