For introductory material relating to “biodegradable” plastics see:

“Factsheet No. 3 : Biodegradability. Exposing some of the myths and facts”

https://www.biobasedconsultancy.com/uploads/files/InnProBio_Factsheet_n3.pdf

"A Review of Standards for Biodegradable Plastics"

Annemette Kjeldsen et al; Industrial Biotechnology Innovation Centre

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/

attachment_data/file/817684/review-standards-for-biodegradable-plastics-IBioIC.pdf

"Biodegradability of Plastics"

Tokiwa, Calabia et al; (2009); International Journal of Molecular Sciences. 2009 Sep; 10(9): 3722–3742.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2769161

For polycaprolactone research see:

“Influence of weather conditions and soil properties on degradation of biodegradable plastics in soil”

Akira Hoshino et al; (2001); Soil Science and Plant Nutrition, 47:1, 35-43. (Note: the data for PCL in table 1 is muddled.)

DOI:10.1080/00380768.2001.10408366

“Biodegradation of aliphatic polyesters soaked in deep seawaters and isolation of poly(ε-caprolactone)-degrading bacteria”

Takayoshi Sekiguchi et al; (2011); Polymer Degradation and Stability 96 1397-1403;

DOI:10.1016/j.polymdegradstab.2011.03.004

"Environmental degradability of polycaprolactone under natural conditions"; 

Katarzyna Krasowska et al; (2016); E3S Web of Conferences 10, 00048;

DOI:10.1051/e3sconf/20161000048

"Microbial degradation of four biodegradable polymers in soil and compost demonstrating polycaprolactone as an ideal compostable plastic". 
Asma S. Al Hosni et al; (2019);

DOI:10.1016/j.wasman.2019.07.042

“Hydrolytic Degradation and Mechanical Stability of Poly(ε-Caprolactone)/Reduced Graphene Oxide Membranes as Scaffolds 

for In Vitro Neural Tissue Regeneration”

Sandra Sánchez-González et al; (2018); Membranes 2018, 8, 12;

DOI:10.3390/membranes8010012

"Photodegradation Mechanisms on Poly(ε-caprolactone) (PCL)"

Danyelle Campos França et al; (2018); Mat. Res. vol.21 no.5 São Carlos 2018 Epub July 16, 2018; 

https://doi.org/10.1590/1980-5373-mr-2017-0837

"Bulk mechanical properties of thermoplastic poly-ε-caprolactone."

Kim Ragaert et al; (2014);

https://www.researchgate.net/publication/270509196_Bulk_Mechanical_Porperties_of_Thermoplastic_PCL

For other aliphatic polyester research see:

“Biodegradable and Biocompatible Polyhydroxy-alkanoates (PHA): 

Auspicious Microbial Macromolecules for Pharmaceutical and Therapeutic Applications”. 

Martin Koller; (2018); Molecules, 23, 362;

DOI:10.3390/molecules23020362

"Poly(4-Hydroxybutyrate): Current State and Perspectives"

Camila Utsunomia et al; (2020); Frontiers in Bioengineering and Biotechnology;

https://doi.org/10.3389/fbioe.2020.00257

“Mineralization of Poly(lactic acid) (PLA), Poly(3-hydroxybutyrate-co-valerate) (PHBV) and PLA/PHBV Blend in Compost and Soil Environments”

Sudhakar Muniyasamy et al; (2016); Journal of Renewable Materials, Vol. 4, No. 2, April 2016;

DOI: 10.7569/JRM.2016.634104