What is meant by biodegradable paper

"Bioplastic"

| bio films | biodegradability

The word BIO implies that a so-called bioplastic is viewed as sustainable and not environmentally harmful.

Some even think that bioplastics could easily be "disposed of" in the environment. You break down there without any problems !?

Biopolymer = bioplastic?


The chemist uses the term POLYMER to describe the fact that many, many MONOMERS combine to form a long chain of the POLYMER.

To delimit the terms, you can think about who put the monomers together to form the polymer?

Was it nature or man?

Real biopolymers


Nature is teeming with polymers: wood, skin, hair, grain starch, algae, mushrooms, muscles, DNA ... countless examples.

Polymers made by plants and organisms can be found everywhere.
HERE the term BIO-Polymer makes sense.

Plastic / plastic


If, on the other hand, humans have created a polymer with chemistry and technology, then one should speak of plastic and omit the prefix BIO.

So these polymers are, do not occur in nature.

For this reason, nature has not developed any degradation mechanisms for these plastics in millions of years.

Unfortunately, the term "bioplastic" has become "imprecise".

Often this refers to plastics produced by chemistry and technology, but which are based on raw materials that were produced by nature.

BIO-BASED is the right term for this.

Bio-based plastic / plastic


Polyethylene (PE) - one of the mass plastics - is usually made from petroleum.

However, PE can also be produced from bio-based raw materials.

Biodegradable

Petroleum-based and bio-based polyethylene is chemically absolutely identical and both are NOT biodegradable.

PE is an artificial polymer brought into the world by humans, nature has no degradation mechanisms for it.

So you can be bio-based and biodegradable not at first set equal. That can be the case, but it doesn't have to be. You have to look carefully!

Raw material sources

In the case of "bio-based" one should also consider which biomass the plastic is actually made of? Do you use biological waste or do you have to cultivate something first in order to extract the raw material from it?

BIO-PE (GREEN-PE) comes mainly from Brazil. There, rainforest was cut down, where sugar cane was grown in order to produce ethanol, which is then ultimately used to produce polyethylene.

The bio-based plastic polylactic acid (PLA) is also based on corn, sugar cane, sugar beet and cassava, all of them food.

Food competition

If you are already clearing forests, shouldn't the acreage gained, the necessary fertilizer and water be better used for food production?

This is a very fundamental question to think through when considering sustainability.

Using grass as a new raw material for papermaking, which is not eaten by cows and which no one else needs, makes sense.

Biodegradable plastics


A plastic is biodegradable if it is broken down into smaller molecules by microorganisms. And these molecules must then be usable in natural metabolic processes, as energy suppliers or for building structures.

There is no BIO polymer in the sense of the above definition that nature does not degrade aerobically or anaerobically again. This is not the case with bio-based PLASTICS.

Aerobic degradability

If atmospheric oxygen is required for biological degradation, one speaks of aerobic degradability.

Anaerobic degradability

If there is no oxygen in the air, other microorganisms come into play, whose metabolism does not require oxygen to break down.

Compostability

Under what exact conditions and within what time does the biodegradability take place?

The EU standard EN 13432 defines an aerobic biodegradability of 90 percent by mass within 6 months for biodegradability.

The certification according to DIN CERTCO applies to the conditions of an industrial composting plant and relates to an aerobic biodegradability of 90 percent by mass within 12 weeks at 60 degrees Celsius.

The ASTM D6400 and the ISO 17088 also line up.

What happens if someone throws a certified bioplastic into a river rather than the garden compost? Is the bioplastic then also biodegradable?

Or it ends up in a biogas plant, which cannot be completely ruled out. Anaesthetic conditions prevail there. A plastic that is certified to be aerobically degradable is not necessarily also anaerobically degradable.

Oxo degradability

The term oxo-degradable sounds harmless at first. Behind this, however, is the concept of "rapid microplastics". You mix non-biodegradable plastics with additives that cause the plastic to "crumble" quickly into small and tiny particles. True to the motto "out of sight, out of mind", microplastics in a fast process.

Oxo biodegradability

Here the approach has been taken further. At the beginning there is also the oxidative "crumbling". The pre-shrunk plastic particles are then further biodegraded by microorganisms. ASTM D6400-04 should be mentioned as a test method. It is a pure laboratory method used to compare different oxo-biodegradable plastics. It also examines the possible environmental toxicity of all breakdown products in the breakdown chain.

Recycling and composting


Recycling companies are pushing for the standardization of packaging plastics and are viewing the new, more exotic, bio-based plastics as contaminants.
Certainly understandable at the moment, as the sorting systems are designed for "normal" plastics. But that does not mean that they cannot be retrofitted to detect new plastics. In 2018 the proportion of "exotic" bio-based plastics was still well below 1%, so that there is still no need for retrofitting. They are sorted out and end up in the incineration.

Even commercial composting companies do not want to have biodegradable plastics in the bio bin, as they do not degrade sufficiently under industrial composting conditions.

Circular economy and bio-based plastics


Material recycling in the sense of the circular economy is certainly the most intelligent solution for plastics. But for this you need chemically resistant, stable, non-biodegradable plastics.

Paper - the solution?


We all know a readily biodegradable material that is sustainably available in large quantities, it is called paper.

There are efforts to improve the barrier properties of paper. Without a barrier against liquids, atmospheric oxygen and aromas, a material is often unsuitable for packaging. It is therefore a worthwhile approach to improve paper in this direction.

But, as it is always advisable, do not decide on your gut instinct, but calculate precisely. There are also cautionary voices regarding the growing use of paper for packaging purposes.

Holistic approach


The CO2 balance speaks in favor of bio-based materials, as the carbon for plant growth was taken from the air in the form of CO2 and only this amount of CO2 can get back into the air during degradation. In the case of petroleum-based plastic, the amount of CO2 is also released into the air.

Manufacturing processes are more or less energy-intensive, use more or less water and fertilizer, even the transport has to be looked at, since heavy materials simply consume more energy during transport. All processes that release CO2.

The carbon footprint and the life cycle analyzes try to represent such relationships in numbers. Not a very simple, complex subject. But there is no getting around it in order to gain meaningful, decision-relevant statements.