Dai tannini del legno una plastica bio-based
SUPSI Image Focus
In the fight against climate change, the world of plastics has long been under scrutiny. Two aspects are attracting attention and concern. On the one hand, the fossil origin of the materials (most plastics are derived from petroleum), and on the other, their end-of-life management. The problem, however, is not so much the amount of petroleum used to produce plastics (about 4-5% of the total extracted each year), but rather what to do with the plastics once their life cycle is over.
With Andrea Castrovinci, head of the Polymer Engineering Laboratory, we try to clarify terms that are too often misinterpreted, partly due to misleading marketing that leads us to believe that ‘biodegradability’ is a concept that can be applied indiscriminately to many objects, as if they were all banana skins. But polymer products derived from petroleum can also be biodegradable.
It is not enough to throw a material labeled “biodegradable” into the environment for it to magically disappear. Castrovinci points out that “biodegradation requires specific conditions of temperature, humidity, and the presence of microorganisms, which are only found in controlled composting facilities. Proper waste management, even of materials labeled as biodegradable, is therefore essential for degradation to actually occur.”
Alongside recycling and biodegradability is the concept of bio-based, which looks at the beginning of the value chain. A material is bio-based when it does not come from fossil sources, but from renewable resources, ideally from waste or by-products and not from raw materials intended for food. Examples of established biopolymers are PLA (polylactic acid) and certain nylons synthesized from castor oil. In these cases, the goal is to reduce dependence on oil without compromising the performance of the material and to achieve a more sustainable carbon footprint.
“At SUPSI, we are working in this direction with a project funded by the Swiss Confederation through the InnoBooster program, in collaboration with the toy company Geomag and Federlegno. The goal is to synthesize a new polymer from tannins, natural substances that can be extracted from wood processing waste. In this way, by replacing fossil raw materials with renewable resources, we achieve a more sustainable carbon balance.”
Tannin, which is normally used in leather tanning or as a low-value residue in the wood supply chain, is here valorized as a raw material for bio-based plastic. The process is not the simplest: researchers start with a liquid solution of tannins, treat it in the laboratory in small chemical reactors, trying to make the molecules react to obtain a polymeric macromolecule. All this is done using a minimum amount of catalysts, which do not alter the ‘green’ nature of the material.
“Our work is still exploratory,” explains Castrovinci, “aimed at verifying the chemical and technological feasibility of a process that, if promising, could be developed on an industrial scale.” The project is part of the innovation process at Geomag, a toy company that has long been committed to using renewable energy and recycled plastic for its products. The goal is to replace petroleum-based plastics with materials derived entirely from renewable sources, without increasing costs for the consumer.
The preliminary results are encouraging: the new material aims to further reduce the climate impact (CO₂ equivalent) compared to the compounds currently in use.
On the other hand, the involvement of Federlegno is crucial: the association helps to identify local suppliers of tannins within the Ticino wood chain, creating a territorial circuit of added value.
It is not enough to throw a material labeled “biodegradable” into the environment for it to magically disappear. Castrovinci points out that “biodegradation requires specific conditions of temperature, humidity, and the presence of microorganisms, which are only found in controlled composting facilities. Proper waste management, even of materials labeled as biodegradable, is therefore essential for degradation to actually occur.”
Alongside recycling and biodegradability is the concept of bio-based, which looks at the beginning of the value chain. A material is bio-based when it does not come from fossil sources, but from renewable resources, ideally from waste or by-products and not from raw materials intended for food. Examples of established biopolymers are PLA (polylactic acid) and certain nylons synthesized from castor oil. In these cases, the goal is to reduce dependence on oil without compromising the performance of the material and to achieve a more sustainable carbon footprint.
“At SUPSI, we are working in this direction with a project funded by the Swiss Confederation through the InnoBooster program, in collaboration with the toy company Geomag and Federlegno. The goal is to synthesize a new polymer from tannins, natural substances that can be extracted from wood processing waste. In this way, by replacing fossil raw materials with renewable resources, we achieve a more sustainable carbon balance.”
Tannin, which is normally used in leather tanning or as a low-value residue in the wood supply chain, is here valorized as a raw material for bio-based plastic. The process is not the simplest: researchers start with a liquid solution of tannins, treat it in the laboratory in small chemical reactors, trying to make the molecules react to obtain a polymeric macromolecule. All this is done using a minimum amount of catalysts, which do not alter the ‘green’ nature of the material.
“Our work is still exploratory,” explains Castrovinci, “aimed at verifying the chemical and technological feasibility of a process that, if promising, could be developed on an industrial scale.” The project is part of the innovation process at Geomag, a toy company that has long been committed to using renewable energy and recycled plastic for its products. The goal is to replace petroleum-based plastics with materials derived entirely from renewable sources, without increasing costs for the consumer.
The preliminary results are encouraging: the new material aims to further reduce the climate impact (CO₂ equivalent) compared to the compounds currently in use.
On the other hand, the involvement of Federlegno is crucial: the association helps to identify local suppliers of tannins within the Ticino wood chain, creating a territorial circuit of added value.