Embracing Sustainability: The World of Bio-Based Polymers in a Mini Review

Abstract

The proliferation of polymer science and technology in recent decades has been remarkable, with synthetic polymers derived predominantly from petroleum-based sources dominating the market. However, concerns about their environmental impacts and the finite nature of fossil resources have sparked interest in sustainable alternatives. Bio-based polymers, derived from renewable sources such as plants and microbes, offer promise in addressing these challenges. This review provides an overview of bio-based polymers, discussing their production methods, properties, and potential applications. Specifically, it explores prominent examples including polylactic acid (PLA), polyhydroxyalkanoates (PHAs), and polyhydroxy polyamides (PHPAs). Despite their current limited market share, the growing awareness of environmental issues and advancements in technology are driving increased demand for bio-based polymers, positioning them as essential components in the transition towards a more sustainable future.

Keywords: bio-based polymers; polymeric materials; polymers; renewable sources; sustainable materials.

Figure 4

Cupriavidus necator DSM 545, a metalophilic strain, containing PHA granules (bright intracellular inclusions) cultivated in continuous mode on glucose as the carbon source, imaged using STEM, magnification ×30,000. Picture taken by E. Ingolić, FELMI-ZFE Graz, and provided by M. Koller, University of Graz, Austria [83].

Figure 1

Plastic production in 2023: (a) global plastic production, (b) European plastic production, (c) bio-based plastic production per country in Europe. The credit for the graphs belongs to PlasticEurope and is attributed to the report ‘Plastic Europe—The Fast Facts 2023’. The graphs have been reproduced with the permission of PlasticEurope [12].

Figure 2

Total number of documents produced on bio-based polymers per year from 1995 to 2003, including both articles and patents. Dimension AI was used as a tool to retrieve the total number of documents per year on the given topic.

Figure 3

Examples of some applications of biopolymers and bio-based polymers.

Scheme 1

(a) optical monomers of lactic acid and stereoisomers of lactide; (b) formation of polylactic acid via polycondensation and ring-opening polymerization.

Figure 5

(a) General structure of polyhydroxy alkanoates (PHAs). Each monomer bears a side chain (-R). Usually, m can range from 1 to 8 carbon atoms, while n ranges from 100 to 3000 units. (b) Representation of some small-chain-length (SCL-HA) and medium-chain-length (MCL-HA) side groups. Adapted from reference [85].

Figure 6

Graphical representation of the possible ways to achieve PHA modification [84,104].

Scheme 2

Polyamide types.

Scheme 3

Hydrogen bond stabilization of the intermediate reaction stage.

Scheme 4

General aminolysis pathway demonstrated by Hoagland et al. [162].

Scheme 5

Synthetic procedure for the synthesis of polyhydroxy polyamides, modified from reference [167], (a) synthetic path involving protection and lactone formation first, (b) polycondensation using diester monomers and (c) more recent polymerization technique using zwitterionic monomers.