Biodegradable material used to mitigate the environmental impact needed to study the biodegradation process. The structural changes by FTIR of two plastic materials, a flexible film made for casting method and extrusion method, with inclusion of cellulose nanoparticles (CNP), using 4 compost kind. Besides, were evaluated biodegradation percentage, under composting conditions with the ISO 4855-1 standard, and soil conditions under the ISO 17556:2019 standard. The tests were carried out for 4 weeks at constant temperature and flow of 58°C ± 2°C and 250 mL / h, using a mature compost (Rejoya, Sultana and Bigfertil®) as inoculum. The structural changes and evolved CO2, were properly evaluated, showing variation in the wavenumbers around of 667 cm-1, 925 cm-1 1016 cm-1, 1417 cm-1 and 1642cm-1, as indicators of the materials biodegradation of two materials. The flexible film with 0%, 5% and 10% of CNP inclusion, showed a mean biodegradation percentage of 91,98%, 87,81% and 89,41% respectively. And in soil conditions, the biodegradation over three weeks were of 7.92%, 7.34% and 6.99% for 0%, 5% and 10% of CNP inclusion respectively.