Visual analysis of all specimens after 15 and 30 days of burial in simulated soil (Fig. 3) showed dark spots distributed in different regions on the surface of the material, suggesting degradation by the action of microorganisms. Comparing the materials, it can be seen that the mass loss (Table 1) was more intensive in the composition with P-VMT (S3), even after burial for 30 days. These results demonstrate the influence on biodegradation of the pre- sence of VMT modified with the phosphonium salt.