“Degradable” Plastics: True Eco-Friendly or Just an Illusion?

If we call the invention of plastic one of humanity’s greatest achievements, it wouldn’t be an exaggeration. From the 19th to the 20th century, over nearly a hundred years, the invention of materials like Parkesine and Nylon laid the foundation for the later explosion of plastic products. During World War II, with the rapid rise of the petrochemical industry, plastics manufacturing developed at lightning speed. Since then, plastic products of all shapes and forms have penetrated every corner of our daily lives.

But as time went on, by the 21st century, the environmental problems caused by plastics gradually drew serious attention. Restrictions and bans on plastic forced this so-called “great invention” off the historical stage. In its place, various so-called “eco-friendly products” appeared, among which “degradable plastics” were widely promoted.

But here’s the question: are degradable plastics truly the best solution for the environment—or just an illusion? Under what conditions can these materials actually degrade? And what impact do they have on today’s waste management systems?

The conditions for biodegradability are complex. Temperature, humidity, oxygen availability, microbial activity—all of these matter. Time is the most crucial factor. For example, conventional fossil-based plastics, like the common PET bottle, take 450–500 years to degrade in the natural environment—completely meaningless from the standpoint of environmental protection.

There are generally two pathways for plastic degradation: photo-oxidative degradation and biodegradation. Photo-oxidative degradation has so far shown no evidence of complete breakdown, so it isn’t practically adopted. Biodegradation, on the other hand, refers to materials that can be fully broken down by microorganisms under certain conditions, converting into carbon dioxide and water. Microbes such as bacteria, fungi, and protozoa can secrete enzymes that cut polyester chains into smaller molecules, eventually turning them into CO₂.

Among today’s biodegradable plastics, PLA (polylactic acid) is the most widely known. In the straw industry, PLA straws are now heavily marketed as “eco-friendly” alternatives.

But here’s the catch: while PLA and similar bioplastics are theoretically biodegradable, in practice they often fall short. Biodegradation requires very strict recycling and treatment conditions. Experts point out that China currently lacks the infrastructure to process biodegradable plastics properly. These materials need industrial composting facilities, but such facilities are very limited. According to national data, by 2019 China had only 142 household waste composting plants, most of which focused on organic waste like crop residue or animal manure—not biodegradable plastics.

So what happens under natural conditions? Studies abroad suggest that if you throw a PLA bottle into the ocean, it could still take hundreds of years to decompose. A German university tested PLA in both seawater and freshwater for 400 days, and the material lost only about 0.5% of its mass. Clearly, natural degradation is extremely difficult. This is the dilemma: PLA’s biodegradability is often theoretical, but rarely achievable in real-world environments.

As a result, even if the theory sounds promising, in practice—given poor waste sorting, lack of composting infrastructure, and processing challenges—PLA and similar bioplastics often end up being incinerated just like regular plastics, defeating their original environmental purpose.

By contrast, in the field of straws, the Gaoyi team has developed a new generation of paper straws made from food-grade single-layer paper. These straws provide a drinking experience comparable to traditional paper straws, but with a key advantage: they are 100% recyclable. Unlike biodegradable plastics that require special composting conditions, Gaoyi’s paper straws can be directly recycled back into pulp to make other paper products. This process generates zero waste and significantly reduces costs related to collection, sorting, and reprocessing—achieving both eco-friendliness and practicality.