Why do plastics not degrade easily ?

Plastics are synthetic polymers primarily composed of long chains of carbon atoms. The fundamental reason for their resistance to degradation is the presence of extremely strong covalent bonds within their C-C backbone [1]. These covalent bonds require significant energy to break, making the polymer structure highly resistant to natural processes such as biodegradation, hydrolysis, and thermal breakdown [3]. Unlike ionic compounds, which have different bonding characteristics, carbon-based polymers rely on these stable shared-electron bonds that microorganisms and environmental factors cannot easily disrupt [2]. While some plastics can be affected by solar radiation or specific chemical treatments, the inherent stability of the covalent molecular architecture ensures they persist in the environment for decades or even centuries [3]. Consequently, the lack of reactive sites and the strength of the covalent network prevent easy decomposition by biological or chemical means.

Sources

1. [1] https://www.sciencedirect.com/science/article/pii/S1878535222005780
2. [3] https://pmc.ncbi.nlm.nih.gov/articles/PMC11478708/
3. [2] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > 4.1 BONDING IN CARBON – THE COVALENT BOND > p. 59