Degradable plastics cannot be degraded. Why is this?

Recently, some people have begun to criticize degradable plastics. Their speeches are mainly in two aspects: if it is said that the degradable plastic has not been completely degraded, then it has been dug up for people to use for many years; if it is said that the degradable plastic has not been completely degraded, and Being crushed into smaller plastic molecules, it will pollute the environment even more.

Misunderstanding 1: You can continue to use it if you dig it out

There is a type of degradable plastics called photodegradable plastic bags, which refers to the addition of initiators to the plastic raw materials to enable the plastics to gradually degrade under the action of light. It is the earlier type of degradable plastics. Since it is mainly degraded by light, how can it be degraded if it is buried in the ground without light?

Misunderstanding 2: Breaking into smaller plastic molecules will increase environmental pollution

With the increasing awareness of humans and the country to protect the environment and resources, it has become a trend to replace non-degradable plastics with degradable plastics.