Abstract
Conventional petroleum-derived plastics represent a serious problem for global pollution because, when discarded in the environment, are believed to remain for hundreds of years. In order to reduce dependence on fossil resources, bioplastic materials are being proposed as safer alternatives. Bioplastics are bio-based and/or biodegradable materials, typically derived from renewable sources. Food waste as feedstock represents one of the recent applications in the research field of bioplastics production. To date, several food wastes have been used as raw materials for the production of bioplastics, including mostly fruit and vegetable wastes. The conversion of fruit and vegetable wastes into biomaterials could occur through simple or more complex processes. In some cases, biopolymers extracted from raw biomass are directly manufactured; on the other hand, the extracted biopolymers could be reinforced or used as reinforcing agents and/or natural fillers in order to obtain biocomposites. The present review covers available results on the application of methods used in the last 10 years for the design of biomaterials obtained from formulations made up with both fruits and vegetables by-products. Particular attention will be addressed to the waste pre-treatment, to the bioplastic formulation and to its processing, as well as to the mechanical and physical properties of the obtained materials.
Highlights
Over the last 50 years, the global production of synthetic plastics, which are carbonbased polymers such as polypropylene, polyethylene, polyvinyl chloride, polystyrene, nylon, and polycarbonate, has continuously increased and it is expected to double in the 20 years
The term bio-based refers to materials or products that are completely or partly derived from renewable resources; the petrochemical resin typical of common plastics is replaced by vegetable or animal polymers and the compounds like glass or carbon fiber or talc are replaced by natural fibers [15]
It was possible to obtain starch-based bioplastic with stronger and midterm elastic property (Tensile strength ranged between 1.6 MPa and 9.0 MPa, while the elongation at break values were between 24.7% and 54.5%, see Table A1)
Summary
Over the last 50 years, the global production of synthetic plastics, which are carbonbased polymers such as polypropylene, polyethylene, polyvinyl chloride, polystyrene, nylon, and polycarbonate, has continuously increased and it is expected to double in the 20 years. Around 80% of nonfuel chemicals produced by the petrochemical industry are sold for the manufacturing of plastics, contributing to environmental pollution as the extraction of oil and gas, hydraulic fracturing for natural gas, releases an array of toxic substances into the air and water, often in significant volumes [5,6,7,8]. Many efforts are being made in the scientific world to found bio-based alternatives which could potentially replace them This has led to the development of a rich and diversified field of research in bioplastic production [15]. The molecular complexity of plant and bacterial biomass provides a wealth of natural bio-based polymers as well as monomeric feedstocks for bioplastic production. A summary table (Table A1), containing all the information relating to the pre-processing of the waste, the definition of the green plastic formulation, and the type of manufacturing, as well as the properties of the final material, will be provided
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