The dilemma of biodegradable packaging

Degradable plastics can be divided into completely biodegradable plastics and destructive biodegradable plastics,as well as light-degradable plastics.

Destructive biodegradable plastics,like the aforementioned oxidatively degradable plastics,currently mainly include starch-modified(or filled) traditional petroleum-based plastics.After the added starch id biodegraded,they are decomposed into smaller petroleum-based plastics fragments.Because microplastics are still produced after decomposition,which is not completely degradable,some countries have begun to ban oxidative biodegradable plastics. (Oxo-degradableplastic).France began to ban this plastic in 2015,and Spain also introduced a similar ban in 2016.Retailers in the UK no longer use plastic bags made of oxidized biodegradable plastic.However,compared with traditional petroleum-based plastics,this type of plastic can be broken in the natural environment,reducing the risk of marine life being killed by accidental eating or being entangled.

Completely biodegradable plastics are made entirely of bio-based materials and can be completely biodegraded into carbon dioxide and water.For example,in Jilin,which has issued a plastic ban,most of the known plastic bags use PLA and PHA plastics.Jilin has also built a special polylactic acid industrial park.

The photodegradable plastic introduce photosensitive groups on the polymer backbone or add photosensitizers,photoinitiattors,etc. to the plastics to give traditional plastics photodegradation properties. Refers to the orderly breakage of polymer molecular chains under the action of sunlight, leading to its destruction and degradation. The light and heat in the natural environment act on the photodegradable plastic, which can decompose large plastic molecules into small molecules. But as the name suggests, in the case of no light (for example, buried in the soil), photodegradable plastics cannot be degraded.