Science and Technology Production
Congress
Authorship
MORALES, FEDERICO
;
Costantino, Alejandra
;
Pettarin, Valeria
Date
2024
Publishing House and Editing Place
18th Conference "Deformation and Fracture Behaviour of Polymers" Polymertec24 Concepts for the Sustainability of Polymer Materials and Polymer Technologies
Summary
Information provided by the agent in
SIGEVA
Plastic waste is one of the main environmental problems of the XXI century. The problem isfurther aggravated by massive use of laminated or multilayer plastic packaging. Food packaging,for example, must meet several specific properties, such as a barrier to water vapor,gases or light, to preserve properties of the products it contains. It is unlike for a single materialto meet all these requirements, and therefore food packages are often made by two ormore materials. Polyolefins and aluminum (A...
Plastic waste is one of the main environmental problems of the XXI century. The problem isfurther aggravated by massive use of laminated or multilayer plastic packaging. Food packaging,for example, must meet several specific properties, such as a barrier to water vapor,gases or light, to preserve properties of the products it contains. It is unlike for a single materialto meet all these requirements, and therefore food packages are often made by two ormore materials. Polyolefins and aluminum (Al) are a common combination of materials infood packaging, both in flexible and rigid containers.An example of flexible multilayer packaging is the one made by polypropylene (PP) and Al,typically used for snacks or cosmetic packaging. The separation of the PP and Al layers intoindividual materials is technically and economically unfeasible. We propose to obtain compositeparticles (micron sized) from post-consumer PP/Al packaging (snacks packaging), toobtain a dual purpose recycled masterbatch: a metallic looking pigment and UV protectoradditive. This masterbatch may be used as high-quality filler for recycled and virgin polypropylenematrices. The recycling process was divided into three stages, which were carefullystudied: cleaning, triturating and conventional extrusion and injection molding processing.PP/Al particles (300-700 microns sized) were obtained, which were processed with a virginpolypropylene in a twin screw mini-extruser to obtain masterbatchs (15, 20 and 25 %wt particles),that were finally used to manufacture real parts with a metallic appearance by injectionmolding. The process was perfomed without the use of polar solvents and liquid nitrogen,which may be expensive and harmful to the environment. Good mechanical propertiesand UV resistance was observed in final pieces.Regarding rigid packaging, the one composed of polyethylene (PE), paper and Al is massivelyused in liquid containers. Nowadays there are several alternatives to reprocess this type ofmultilayer waste, such as hydrapulping, trituration, chemical separation of individual layersand incineration. However, these methods are not desirable from technical, environmentalor economic issues. We propose an innovative alternative to recycle them, which consists inreusing the packaging without trituration, by adding discarded milk pouch packaging, anothermultilayer waste based in PE and polyethylene vinyl alcohol (EVOH). The idea was to conformplaques of different thickness by compression molding to replace wood agglomerates.The recycling process involves cleaning without the use of aggressive solvents, drying andcompression molding. Obtained plaques presented not only good mechanical performance,but also improved thermal insulation properties.In summary, pieces obtained with these alternative recycling methodologies, beyond presentinggood mechanical performance and a good appearance, also meet the fundamentalrequirement of being easily processable using conventional industrial processing techniques,overcoming several of the main problems of recycled materials.
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Key Words
polypropylenemultilayer filmsaluminiummechanical recycling