Overall, due to the complexity of the production process of degradable plastics, it is often difficult to collect and recycle. Like traditional plastics, degradable plastics may eventually enter landfills or incinerators or pollute the marine environment. In addition, one-sided emphasis on its biodegradability may lead to the disposal of related wastes at will, pollution of recyclable wastes and the cost of adding biomass wastes for treatment. If the production of degradable plastics increases as rapidly as the profession expects, it will certainly increase the pressure of land environmental protection and cause environmental and social conflicts.
The debate about whether degradable plastics should replace traditional plastics has now arisen around the world. In fact, the real problem is that there is an urgent need to reduce the use of all plastics, especially the overuse, unnecessary use and disposable use of plastics. Excessive consumption and disposable culture are the root causes of plastic environmental problems. Skills innovation and material substitution can not solve them. On the contrary, we need to change the production mode of enterprises and the consumption mode of the public, and call on the government to give priority to preventing the occurrence and recycling of plastics. On this premise, it is a reasonable choice to develop degradable plastics conditionally and ensure that they do not consume natural resources excessively, have high recycling efficiency and can help to prevent the occurrence of waste.
Common degradable plastics are either derived entirely from biomass (such as sugar, starch or lignocellulose), converted entirely from non-biomass materials such as petroleum, or a mixture of biomass and non-biomass plastics. Now, only when the relevant skills and facilities are complete, can the degradable plastics on the market be partially or fully degraded by microorganisms into natural elements (such as water, carbon dioxide and biomass). Plastic products that can be biodegraded in the marine environment are still very rare. The "degradability" determined by the European Packaging Compost Standard (EN 13432) should also satisfy stringent industrial treatment conditions.
Over the past half century, global plastic production has increased 20-fold, from 15 million tons in 1964 to 322 million tons in 2015; if this rate remains unchanged, it is expected to double in the next 20 years. At the same time, the European Plastics Professional Association estimates that 70% of plastic waste occurs in Europe every year is landfill or incinerated, and only 30% is recycled. This low recovery rate is unlikely to be improved due to the limitations of existing skills and the proliferation of disposable plastic products of inferior quality.
In order to get rid of the dependence on fossil fuel resources and reduce greenhouse gas emissions, governments and industries are looking for other sources of plastics besides oil. Over the next few years, global production capacity of bio-based plastics is expected to more than triple, reaching 7.85 million tons in 2019.