Bio Degradable plastics are not YET a reality. There is a great number of Academic Research devoted to this problem. Since this problem is recognized as "vital" - it is well funded - the latter is one of the main reasons attracting researchers. Currently, however, the main approach to bio-degradation is the study of the degradation of polymers by the action of microorganisms living in soil. This is a long process and great success has not yet been achieved. Apparently, it is necessary to introduce some substances catalyzing bio-degradation. However, it is completely unclear how they will affect the soil micro-fauna.

The fresh ideas - are needed - apparently not bio-decomposition but recycling

https://www.researchgate.net/publication/258211268_Thermoplastic_starches_Properties_challenges_and_prospects

Everyone dosen't know about the bio-degradable plastic contained wih chemical material and associated environmental problems. Now that new bio-degradable plastic shopping bags have been introduced in the market. How those plastic can be bio-degradable and where is chemical particle goinig ? There are two ploblems. We shall be belived to use the pure bio-degradable nature of plastic as SDGs. from Fukuda Mitsuo

Biodegradable polymers are theoretically possible.There are many problems making this property of plastics a reality.

I think bio-degradable plastics is in its initial stage. Until now it is not a reality. If we introduce bio-degradable plastic, its use will be very limited. In the meantime we should focus on recycling and re-use. Non bio-degradable plastic 🛍 can't be avoided. It is part of our life and will be there, even if bio-degradable plastic is also available. Bio-degradable plastic will be simply an addiction to the present system, it can't replace non bio-degradable plastic 100%.

In short, non bio-degradable plastic will exist. Therefore, we have to work on recycling of waste plastic. It present only PET bottles are recycled through out the world. We have to think about polythene bags also.

Later on biodegradable plastics will also be known as not completely degraded and new hazardous by products are coming in environment

Again there will be slogan say no to degradable plastic

Yes Satish Narula, you are 100% right 👉.

How about polyhydroxybutyrate (PHB) ?

And also polycaprolactone (PCL). It is widely used in medical application.

And how about PHB ?

And how about to use instead plastic bags - "Cat's Cradles" ?

Dear Leonid V Vladimirov,

This "Cat's Cradles" is new for me, and I am not clear on this concept . If you have time, please elaborate.

Regards

Dear Prof. Mohammad:

I am not good in the art of drawing.

"Cat's Cradle" is a game with a string. It usually involves two. The string is stretched between the fingers of both hands, and then gently transferred to the hands of the partner in the game, but so that he can make a new plexus. It seems to me that in my description this old game is impossible to imagine. Therefore, I refer you to the wonderful book of Kurt Vonnegut, which is called: "Cat's Cradle"

to Prof. Mohammad:

P.S. This book has played a decisive role in my life.

Yes Leonid V Vladimirov,

I got it

Interesting..

Mitsuo Fukuda , I have heard the same things about biodegradable plastics.

However, I saw this in Mitsubishi Chemical Website. According to this this polymer is degraded into CO2 and water (however, the time frame is not given) So it is bit tricky.

"Polybutylene succinate (PBS) is the biodegradable plastic that decomposes into water and carbon dioxide with the microorganism under the soil. PBS has a high heat resistance among the general biodegradablility resin, and PBS has high compatibility with a fiber. Using these goodness, it's possible to achieve the performance which can't be shown by itself as the compound with other resin and material.duct life cycle." https://www.m-chemical.co.jp/en/products/departments/mcc/sustainable/product/1201025_7964.html

Dear Amila Abeynayaka san,

Thank you for your reply.

In the coming years, we are beginning to need and be able to biodegrade within a couple of years and use safe biodegradable polymers that do not truly leave the form of waste. On this occasion, we propose that it is necessary to consider biodegradable polymers and their environmental destruction and their effects on the living body. That is, there are big problems that can not be solved only by the characteristics of biodegradability.

Polybutyl succinate (PBS) is as you are told materially to hit. However, at the stage of molding processing into products, additives (chemical substances) are added and used for pellets compounded with other polymers. I have not heard that PBS alone is used without additives (chemical substances) and molded products are sold. In addition, other polymers for compounds also contain additives (chemical substances).The reason why it is used is because there are cost factors that match the plastic molding performance of petrochemicals. Additives are mainly crystallization agents, plasticizers and stabilizers. In other words, I would like to say that these additives after being biodegraded are eluted in molecular units and what kind of influence they have on the living body and the environment, and then most specialists closed their mouths about this. You are by all means, researchers in materials science are well aware of what is included in the final product and advocacy is to carry out material design. This is what I believe is a major contribution to the SDGs, which is a global recognition and advocacy.

We have finished molding products with PBS and PLA compounds and have experience in molding conditions and additive safety. In Japan, there are lawsuits against the case of Kanemi Oil Case with regard to additives and even asbestos in inorganic substances without additives, and the safety of materials is being questioned more than ever. Finally I use 100% PLA without additives and market the molded products to the world.

Biodegradablity of polymers is a reality, it can be achieved through blending.

It is a common knowledge that most of applications of polymers are in packaging consumables, therefore the Blends that can be incorporated into polymer matrix should have the following properties:

1) Biodegradablity

2) Non toxicity

3) considerable mechanical properties

4) low water Absorption.

The blends that have properties close to the above are Cellulose and plasticized starch.

This is a new research interest which we can conduct to ascertain optimum blend composition that will yield biodegradablity without sacrificing the initial properties of the polymer.

Biodegradable plastic like PHB, PHA, PCL is now widely used in some special applications only. Like surgery suture, the string used that is intent for human body to absorb, no need to remove, the string to hold artificial joints , etc.

Another typical application is for denitrification, like PHB, PCL, PBS, to remove highly soluble nitrate for soil, for freshwater or sea water. It makes use of the plastic biodegradable properties. Feed bacterias creating enzymes or microbes to achieve denitrification.

PLA is often used for 3D printing for hobbiests. PLA is made from corn. It is arguable whether it is real biodegradable.

Consumer products or packaging material to use biodegradable plastic is difficult. It makes the products less durable. The cost is usually higher. That is to pay more to buy a less durable product. Just imagine if you buy a cell phone. There is an expiry date for the plastic casing and internal components. And it is difficult to control the biodegradable rate under different circumstances, temperature, humidity, Sunshine (UV), sweating, etc.

Thank Alfred Cheng-san

Since no additional comments have been delivered, I will propose again.

Biodegradable plastics do not generate microplastics compared to conventional petrochemical plastics. It is thought that environmental damage caused by this will be reduced. But I think it needs to be reconsidered. The biodegradable material that she pointed out seems to have no problem as a material. So, when used in the final product, the safe properties of the original material will change. In other words, in order to perform the molding process, the original material contains many chemical substances such as a plasticizer and a release agent. Therefore, these chemical substances are eluted by biodegradation. Also, whether these chemicals are safe and friendly to humans and the environment when discarded is a major issue.Since no additional comments have been delivered, I will propose again.

Biodegradable plastics do not generate microplastics compared to conventional petrochemical plastics. It is thought that environmental damage caused by this will be reduced. But I think it needs to be reexamined, except for biodegradable materials used in medical implants. The biodegradable material that you pointed out seems to have no problem as a material. So, when used in the final product, the safe properties of the original material will change. That is, they contain many chemical substances such as plasticizers and mold release agents in the original material for molding. Therefore, these chemical substances are eluted by biodegradation. Also, if these chemicals are disposed of, whether they are safe and friendly to humans and the environment remains a major issue.

Interesting question. Out of my interest area. I will follow.