Skip to content

Chemistry · Ch 15 — Polymers

Biodegradable Polymers

15.4

Biodegradable Polymers

Why some polymers are made to break down

Most everyday polymers are deliberately built to be tough and resist breaking down — which is great for durability, but means they persist as solid waste in the environment for a very long time, causing serious environmental problems. This has driven the design of biodegradable synthetic polymers, engineered to carry functional groups similar to those found in natural biopolymers, so that natural biological processes can degrade them.

One important class of biodegradable polymers is the aliphatic polyesters. Two examples:

  • PHBV (poly-β-hydroxybutyrate-co-β-hydroxyvalerate) — a copolymer of 3-hydroxybutanoic acid and 3-hydroxypentanoic acid:

CH3−CH(OH)−CH2−COOH  +  CH3−CH2−CH(OH)−CH2−COOH  ⟶  −[O−CH(CH3)−CH2−CO−O−CH(CH2CH3)−CH2−CO]−nCH_3{-}CH(OH){-}CH_2{-}COOH \;+\; CH_3{-}CH_2{-}CH(OH){-}CH_2{-}COOH \;\longrightarrow\; {-}[O{-}CH(CH_3){-}CH_2{-}CO{-}O{-}CH(CH_2CH_3){-}CH_2{-}CO]{-}_n

PHBV is used in speciality packaging, orthopaedic devices, and controlled drug-release systems, and it undergoes genuine bacterial degradation in the environment. …

Start your 14-day free trial to unlock the full solution →
← Previous · 15.3Molecular Mass of PolymersNext · 15.5 →Polymers of Commercial Importance