Trends in Sustainable Biobased Packaging Materials: A Mini Review

Petroleum-based polymers have served the packaging industry in numerous ways as films, pouches, rigid containers, foamed containers, and other components for food, medical, and other packaging applications. However, growing concerns about environmental impact, awareness of greenhouse gas emission and their adverse effects, increased oil prices, and disposal and landfill issues are forcing researchers and the industry to develop sustainable packaging. Biobased materials, those derived from biological sources rather than petroleum sources, are ideally suited to meet these new sustainability requirements. Although biobased materials such as paper have been used for packaging extensively, packaging with increased functionality and performance is needed. Therefore, the movement toward sustainable packaging will include both improving current biobased packaging and development of new biobased materials such as biopolymers. The aim of this mini review was to offer a summary of the current state of biobased packaging as well as provide insight into current and future trends of sustainable paperand bioplastic-based materials for packaging industry. © 2021 Elsevier Ltd. All rights reserved. 1. Current global packaging market and materials The world packaging market is continuously growing. The most recent data from industry analyst Smithers Packaging report that the global packaging market was worth $914.7 billion in 2019, having increased by 8.4% in value terms since 2015. This market was expected to rise further but in 2020, the world faced an unprecedented global challenge in the COVID-19 pandemic, which has considerably affected the packaging market. Without considering the probable and long-term COVID-19 impact, industry experts estimated the global packaging market to be valued at $939.9 billion in 2020 and was forecasted to grow at a compound annual growth rate of 2.3% to 2025 reaching a value of $1.05 trillion. An additional market expansion is predicted across 2025e2030 at almost 1.8% annual growth rate, reaching a global value of over $1.15 trillion [1]. The fastest market growth during this period is projected to occur in the emerging and developing nations of Asia, Africa, the Middle East, and Eastern Europe due the rising real incomes, growing population, demographic changes, rising urbanization, the further development of a retail infrastructure, and so on. These leading economic and demographic trends coupled with the ). spread of the Internet and the ensuing rapid growth of the global ecommerce industry will result in a rapid expansion in demand for packaged goods in sectors such as food, beverages, cosmetics, and pharmaceuticals. In contrast, a slower growth is predicted for the more mature packaging markets such North America, Western Europe, and Australasia [1]. The global packaging materials market has been segmented into paper/paperboard, flexibles (almost 64% being plastics), rigid plastics, metals (steel and aluminum), glass, and others (wood, textiles, etc.) [1,2]. Paper/paperboard and plastics constitute the largest fraction of packaging materials used (78%) followed by metals, glass, and others (Fig. 1) [1]. This review will focus on paper/paperboard and both flexible and rigid plastics, which are the most widely used materials within the global packaging market, accounting for a value share of more than 70%. Among these materials, the packaging sustainability credentials for paper/paperboard continue to be strong due to its high recycling rate and the organic nature of the raw materials (trees) used to make it, which are sourced today from sustainably managed forests (e.g. Forestry Stewardship Council [FSC]ecertified forests). In contrast, most common flexible and rigid plastics used in packaging are petrochemical based and under increased environmental pressure to improve their sustainability credentials because they are not sourced from renewable materials and/or biodegradable so they pose serious ecological problems [3]. Fig. 1. Percent share in 2020 of the global packaging market by material type. Adapted from Ref. [1]. N.M. Stark and L.M. Matuana Materials Today Sustainability 15 (2021) 100084 According to the US-Environmental Protection Agency, more than 68% (68.2%) of paper and paperboard and less than 9% of plastics (8.7%) were recycled in 2018 in the United States [4,5], whereas the worldwide recycling rates were estimated at approximately 70% for paper-based packaging and 14% for plastic packaging [6]. Most of thesematerials are easily recyclablewhen used as a single material in packaging formats, for example, uncoated paperboard or corrugated cardboard. Unfortunately, packaging materials are often combined in different structures such as laminates, multilayers, coated materials, and so on, making their recycling impracticable and most of the times economically not convenient. Since they are either landfilled or incinerated at the end of their lives, these packaging materials have raised serious environmental concerns [1,7]. 2. Consumer preferences and industry responses The continued global economic and population growth, demographic changes (e.g. growth of the urban consumer base, the rising life expectancy, etc.), coupled with other changes in consumer lifestyles have resulted in an increased demand for packaged convenient and single-serving foods, durable and non-durable goods, healthcare/pharmaceutical products, and so on [8]. These changes have also increased the amount of packaging materials needed tomeet consumer’s demand; thus, resulting in an increased generation of municipal solid waste. Packaging waste remains a growing environmental concern and there is mounting public pressure by consumers worldwide for sustainable materials due to their growing environmental awareness and desire to preserve the environment [9,10]. The environmental public pressure is being backed by stringent legislations around the world banning specific materials derived from fossil fuels (e.g. single-use plastic packaging), mandating recycling, seeking more sustainable packaging material alternatives [10e15]. In response to changing consumer preferences and emerging regulatory policies, many brands and retail chains are committing to transition away from non-recyclable and difficult to recycle multilayer flexible packaging materials in favor of more recyclable, compostable, or biodegradable materials, eco-friendly, and sustainable alternatives [10e15]. Sustainable packaging, defined by the Sustainable Packaging Coalition as a packaging that, over time, reduces its environmental impact and footprint [16], is becoming one of the fastest growing 2 packaging sectors and is therefore identified as a priority for both the industry and consumers. Several large brand companies and their suppliers have introduced sustainability agenda in their business plans in the past few years. For examples, in 2015, PepsiCo introduced its 2025 sustainability agenda, which includes the intent to make 100% of its packaging recoverable or recyclable. As part of this, they plan to move toward completely biodegradable snack food packaging [17]. Similarly, Kraft Heinz announced in 2018 its strategy to make 100% of its packaging globally sustainable by 2025 [18]. Likewise, McDonald’s announced recently that its packaging will be 100% renewable and recycled by 2025 [19]. Sustainable packaging is also supported by the New Plastics Economy Global Commitment led and launched in October 2018, by the Ellen MacArthur Foundation in collaboration with the United Nations Environment Programme [20]. This Global Commitment unites businesses, governments, and other organizations across five continents behind a common vision of a circular economy for plastics and 2025 targets to address plastic waste and pollution at its source, starting with packaging. To deliver a world without plastic pollution, the global commitment urges the industry and policymakers to develop regulations and strategies to accelerate advanced recycling innovations that will dramatically reduce plastic waste in oceans and landfills. Moreover, major brands worldwide have started to incorporate recycled plastics in their packaging due to recent advances in recycling technologies and legislations encouraging greater recycling and use of recycled content in packaging [21]. Packaging plays an extremely crucial role in our society by not only helping to prevent food loss and waste but also reducing energy use from the transportation and shipping of goods, among others. However, concerns over the large quantity of waste materials generated by the packaging industry are rising, and sound solutions are needed from the industry and policy makers. There is no doubt that the growing consumer concern over the preservation of the environment will drive demand for not only a circular economy for plastics, in which plastics typically are reused rather than discarded, but also for more sustainable packaging, based on renewable resources; concepts that will be described in the following sections. 3. Sustainable packaging materials 3.1. Wood fiberebased materials Cellulose is the most abundant biopolymer and therefore is a valuable, readily available resource for sustainable packaging applications. Cellulose may be derived from biomass such as wood, forestry residues, agricultural residues, algae, plants, and some bacteria. In this article, we discuss packaging materials derived from wood-based cellulose fibers. Cellulose, hemicellulose, and lignin are other primary wood components which are found in varying quantities depending upon the sourced material. The wood cell wall may be comprised of 40e50% cellulose, whichmust be isolated from wood for wood fiberebased packaging [22]. Methods to isolate cellulose can impact the cellulose fiber morphology and chemical composition, which results in different packaging applications [23]. Cellulose fibers can contribute to sustainable packaging in