Bioplastic

Biodegradable plastic utensils
Flower wrapping made of PLA-blend bio-flex

Bioplastics are plastic materials produced from renewable biomass sources, such as vegetable fats and oils, corn starch, straw, woodchips, sawdust, recycled food waste, etc. Some bioplastics are obtained by processing directly from natural biopolymers including polysaccharides (e.g., starch, cellulose, chitosan, and alginate) and proteins (e.g., soy protein, gluten, and gelatin), while others are chemically synthesised from sugar derivatives (e.g., lactic acid) and lipids (oils and fats) from either plants or animals, or biologically generated by fermentation of sugars or lipids. In contrast, common plastics, such as fossil-fuel plastics (also called petro-based polymers) are derived from petroleum or natural gas.

One advantage of bioplastics is their independence from fossil fuel as a raw material, which is a finite and globally unevenly distributed resource linked to petroleum politics and environmental impacts. Life cycle analysis studies show that some bioplastics can be made with a lower carbon footprint than their fossil counterparts, for example when biomass is used as raw material and also for energy production. However, other bioplastics' processes are less efficient and result in a higher carbon footprint than fossil plastics.[1][2][3]

The distinction between non-fossil-based (bio)plastic and fossil-based plastic is of limited relevance since materials such as petroleum are themselves merely fossilized biomass. As such, whether any kind of plastic is degradable or non-degradable (durable) depends on its molecular structure, not on whether or not the biomass constituting the raw material is fossilized. Both durable bioplastics, such as Bio-PET or biopolyethylene (bio-based analogues of fossil-based polyethylene terephthalate and polyethylene), and degradable bioplastics, such as polylactic acid, polybutylene succinate, or polyhydroxyalkanoates, exist. Bioplastics must be recycled similar to fossil-based plastics to avoid plastic pollution; "drop-in" bioplastics (such as biopolyethylene) fit into existing recycling streams. On the other hand, recycling biodegradable bioplastics in the current recycling streams poses additional challenges, as it may raise the cost of sorting and decrease the yield and the quality of the recyclate. However, biodegradation is not the only acceptable end-of-life disposal pathway for biodegradable bioplastics, and mechanical and chemical recycling are often the preferred choice from the environmental point of view.[4]

Biodegradability may offer an end-of-life pathway in certain applications, such as agricultural mulch, but the concept of biodegradation is not as straightforward as many believe. Susceptibility to biodegradation is highly dependent on the chemical backbone structure of the polymer, and different bioplastics have different structures, thus it cannot be assumed that bioplastic in the environment will readily disintegrate. Conversely, biodegradable plastics can also be synthesized from fossil fuels.[1][5]

As of 2018, bioplastics represented approximately 2% of the global plastics output (>380 million tons).[6] With continued research on bioplastics, investment in bioplastic companies and rising scrutiny on fossil-based plastics, bioplastics are becoming more dominant in some markets, while the output of fossil plastics also steadily increases.

  1. ^ a b Rosenboom, Jan-Georg; Langer, Robert; Traverso, Giovanni (2022-02-20). "Bioplastics for a circular economy". Nature Reviews Materials. 7 (2): 117–137. Bibcode:2022NatRM...7..117R. doi:10.1038/s41578-021-00407-8. ISSN 2058-8437. PMC 8771173. PMID 35075395.
  2. ^ Walker, S.; Rothman, R. (2020-07-10). "Life cycle assessment of bio-based and fossil-based plastic: A review". Journal of Cleaner Production. 261: 121158. doi:10.1016/j.jclepro.2020.121158. hdl:10871/121758. ISSN 0959-6526. S2CID 216414551.
  3. ^ Pellis, Alessandro; Malinconico, Mario; Guarneri, Alice; Gardossi, Lucia (2021-01-25). "Renewable polymers and plastics: Performance beyond the green". New Biotechnology. 60: 146–158. doi:10.1016/j.nbt.2020.10.003. ISSN 1871-6784. PMID 33068793. S2CID 224321496.
  4. ^ Fredi, Giulia; Dorigato, Andrea (2021-07-01). "Recycling of bioplastic waste: A review". Advanced Industrial and Engineering Polymer Research. 4 (3): 159–177. doi:10.1016/j.aiepr.2021.06.006. hdl:11572/336675. S2CID 237852939.
  5. ^ "Bioplastics (PLA) - World Centric". worldcentric.org. Archived from the original on 2019-03-09. Retrieved 2018-07-15.
  6. ^ Chinthapalli, Raj; Skoczinski, Pia; Carus, Michael; Baltus, Wolfgang; de Guzman, Doris; Käb, Harald; Raschka, Achim; Ravenstijn, Jan (2019-08-01). "Biobased Building Blocks and Polymers—Global Capacities, Production and Trends, 2018–2023". Industrial Biotechnology. 15 (4): 237–241. doi:10.1089/ind.2019.29179.rch. ISSN 1550-9087. S2CID 202017074.