Sustainable Polymer Technologies

Dear Colleagues,

The Food and Agriculture Organization of the United Nations (FAO) states that approximately one-third of the food addressed to human consumption is currently lost or wasted globally. It also estimates that the direct costs for producers of food going to waste amount to approximately $750 billion every year. In a global context of limited natural resources, it is more effective to reduce food waste than to increase food production. Packaging can definitively play a major role in food waste by extending the shelf life of food items and providing safe food products to consumers. In the last years, polymers have been the key enablers for food preservation and protection due to their balanced properties and high versatility. Then, plastics materials, that is, polymers with additives, have strongly contributed to the needs of global changing demographics and the progress of modern society. However, the plastics economy is still based on a linear model of “make, use, and dispose of,” and most of the plastic packaging material value is lost to the economy after a first short use cycle. Furthermore, hundreds of millions of tons of plastics escape collection systems, ending up in the environment whether as microscopic particles or surviving in a recognizable form for hundreds of years.

The circular economy has recently become a widespread concept that aims to eliminate the concept of waste, rebuild natural capital, and create economic value by using—not consuming—resources effectively. In the food packaging area, the game-changing strategy deals with the promotion of sustainable polymer technologies that decouple plastics from fossil feedstocks, drastically reduce the leakage of plastics into natural systems, and increase the quality and uptake of plastic recycling. Current strategies in circular economy scenarios are steering the development of biopolymers for single-use applications such as food packaging and food contact disposables. Biopolymers comprise a whole family of materials that include either “bio-based” polymers or “biodegradable” polymers as well as polymers featuring both properties. Bio-based polymers refer to any kind of polymer that is produced from renewable resources, which include both naturally occurring polymers (biomacromolecules) and synthetic polymers produced by means of natural monomers. Biodegradable polymers are macromolecular materials whose physical and chemical properties undergo deterioration and completely degrade when exposed to the enzymatic action of microorganisms producing carbon dioxide (aerobic process), methane (anaerobic process), water (aerobic and anaerobic processes), and inorganic compounds and biomass. Bio-based polymers can potentially save fossil resources by using biomass that regenerates annually and contribute to advancing carbon neutrality, whereas biodegradability is an add-on property that offers additional means of recovery at the end of a product’s life.

Today, bio-based polymers are mostly made of carbohydrate-rich plants such as corn or sugar cane, the so-called food crops or “first-generation feedstock”. This is currently the most efficient route for the production of bioplastics because it requires the least amount of land to grow and produces the highest yields. It includes corn, wheat, sugarcane, potato, sugar beet, rice, and edible plants or oils. Nevertheless, this feedstock also shows negative impacts such as deforestation of protected areas and environmental damage caused by bad agricultural practice, which must be avoided. Moreover, the discussion about the use of biomass for industrial purposes is still often linked to the question of whether the conversion of potential food and feedstock into materials is ethically justifiable. Thus, in this scenario, the use of biomass could ultimately ensure the highest value creation and the strongest environmental benefits. Thus, in the near future, innovative technologies should be refocused on non-edible biomass and industrial by-products and wastes as the main source for bioplastics. These novel raw materials represent the so-called second- and third-generation feedstocks that include large amounts of agro-food residues, non-food crops, or cellulosic biomass, which are abundant and currently have low economic value. From the above, the new trend for the development of sustainable polymer technologies will be led by the emergence of new biopolymers made from renewable and non-food sources.

Prof. Dr. Sergio Torres-Giner
Prof. Dr. Maria Vargas
Topic Editors