_applied_  
_sciences_  
_Editorial_  
Sustainable Polymer Technologies for a Circular Economy  
**[PERSON]**  
Research Institute of Food Engineering for Development (IIAD), Universitat Politecnica de Valencia (UPV),  
Camino de Vera s/n, 46022 Valencia, Spain; storresginer@upves  
We inhabit a defining moment in history. It is a moment in which the scientific community has united to agree on an ambitious framework with which to resolve the environmental issues associated with plastic waste. Plastics are the \"workhorse\" material of the modern economy, offering multiple functions that help tackle several challenges facing our society. Plastics production has increased from 15 million tons in the 1960s to 311 million tons in 2014 and is expected to triple by 2050 as plastics come to serve increasingly more applications. Packaging is the dominant sectoral use of plastics globally, representing nearly 40% of the plastic market. However, after an initial short use cycle, most of the economic value of plastic packaging material is lost. Furthermore, hundreds of millions of tons of plastics escape collection systems, ending up in the environment either as microscopic particles or surviving in a recognizable form for hundreds of years. Therefore, it is high time to implement the principles of Circular Economy in the plastics industry. The Circular Economy has recently become a widespread concept, emerging in the past few decades from several schools of thought, such as \"Cradle2 Cradle\" and \"Biomimicry. It envisages a novel economic model that is restorative and regenerative by design, wherein its key aims are to eliminate the concept of waste, rebuild natural capital, and create economic value by using--not consuming--resources effectively. However, the current economic system of the plastics industry still follows the linear model'make, use, and dispose', which erroneously assumes that economic growth can be based on the abundance of resources and unlimited waste disposal. According to the model outlined in the New Plastics Economy and other recent sustainable initiatives, strategies of Circular Economy regarding the plastics industry entail promoting sustainable polymer technologies that decouple plastics from fossil feedstocks, drastically reduce the leakage into and the effects of plastics on natural systems, and create an effective after-use plastics economy. This Special Issue focuses on recent research studies devoted to enabling better economic and environmental advances in the plastic packaging value chain that can successfully accelerate the transition of the plastics industry from its traditional linear economy to a more valuable and sustainable model. The polymers used to produce plastics, together with the corresponding additives, should not require petroleum or other fossil fuels as feedstocks. In this context, pectin, one of the most abundant polysaccharides in nature, can be applied to produce biodegradable, biocompatible, and water-soluble films as well as coatings or interlayers in biopolymer-based structures of interest in food packaging. In this regard, [PERSON] et al. [1] prepared and characterized glycerol and polyethylene oxide-2000 (PEO2000)-containing pectin films via electrospinning and the subsequent annealing of the resultant fiber mat at temperatures below 160 \({}^{\circ}\)C. These newly developed pectin films were fully characterized and thereafter applied as interlayers between two external layers of poly(3-hydroxybutyrate-_co_-3-hydroxyvalerate) (PHBV). The resultant fully bio-based and biodegradable multilayer film presented a strong barrier to water and limnence vapors, revealing their promising potential in food packaging applications. Similarly, [PERSON] et al. [2] developed fully bio-based materials using thermoplastic starch (TPS) that was obtained from corn plasticized with water and glycerol, which was blended with up to five different pine resin derivatives as a kind of natural additive.