Environmental concerns over waste plastics’ effect on the environment are leading to the creation of biodegradable plastics. Biodegradable plastics may serve as a promising approach to manage the issue of environmental accumulation of plastic waste in the ocean and soil. Biodegradable plastics are the type of polymers that can be degraded by microorganisms into small molecules (e.g., H2O, CO2, and CH4). However, there are misconceptions surrounding biodegradable plastics. For example, the term “biodegradable” on product labeling can be misconstrued by the public to imply that the product will degrade under any environmental conditions. Such misleading information leads to consumer encouragement of excessive consumption of certain goods and increased littering of products labeled as “biodegradable”. This review not only provides a comprehensive overview of the state-of-the-art biodegradable plastics but also clarifies the definitions and various terms associated with biodegradable plastics, including oxo-degradable plastics, enzyme-mediated plastics, and biodegradation agents. Analytical techniques and standard test methods to evaluate the biodegradability of polymeric materials in alignment with international standards are summarized. The review summarizes the properties and industrial applications of previously developed biodegradable plastics and then discusses how biomass-derived monomers can create new types of biodegradable polymers by utilizing their unique chemical properties from oxygen-containing functional groups. The terminology and methodologies covered in the paper provide a perspective on directions for the design of new biodegradable polymers that possess not only advanced performance for practical applications but also environmental benefits.

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Amorphous and semi-crystalline polyester polyols based on a novel, low cost, bio-based 1,5-pentanediol (Bio-PDO) were synthesized and formulated into solvent-borne coatings and hot melt adhesives. Bio-PDO may provide a lower cost, more sustainable, and non-petroleum-based alternative to polyols based on 1,6-hexanediol (HDO). The polyester polyols were characterized for end group composition, monomer incorporation, and thermal transitions. Bio-PDO-based coatings exhibited performance, including hardness, flexibility, adhesion strength, and solvent resistance, similar to the coatings based on petroleum-derived HDO. Bio-PDO-based adhesives exhibited lower green strength (initial adhesion strength) and longer open time (workable time to bond substrates) than HDO-based adhesives. The effects of common bio-based impurities, including lactones and mono-alcohols (δ-valerolactone and tetrahydrofurfuryl alcohol as examples of impurities), on polyester polyols were investigated. Hydroxyl functionalities of polyols were controlled by the excess diols in monomer feeds and were not impacted largely by the δ-valerolactone levels. High-level tetrahydrofurfuryl alcohol terminated the polyester ends with unreactive functionality. Deleterious effects on polyol hydroxyl functionality are not expected at the low impurity levels (<2 wt %) found in leading bio-PDO processes.