Synthesis of bio-based polyamide from biogenic residues

A research team from the Fraunhofer Society and the Technical University of Munich (TUM) led by chemist Volker Sieber has developed a new polyamide family which can be produced from a byproduct of cellulose production – an example for a more sustainable economy with bio-based materials.

Polyamides are important plastics. They can be found in ski bindings and in cars or items of clothing. Commercially, they have been made predominantly from crude oil up until now; there are just a few “green” alternatives, such as polyamides based on castor oil.

Bio-based compounds are often more expensive to produce and have therefore only been able to penetrate the market before now if they have had particular properties.

A team led by Volker Sieber, Professor of the Chemistry of Biogenic Raw Materials at TU Munich, has now developed a completely new polyamide family which can be produced from a byproduct of cellulose production.

New polyamide family

The biogenic starting material, (+)-3-carene, is made up of two rings which are fused to one another. The chemists at the TUM and the Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB) in Straubing have now modified one of the rings in such a way that it can be opened up, yielding a long chain of molecules, a polymer. In this process, the second ring remains intact. In this way, instead of a linear polymer chain like in traditional polyamides, a chain which bears many small rings and other side groups emerges. This gives the polymer completely new functions.

Special properties

The new polyamides have special properties which make them attractive for many applications. For example, they melt at higher temperatures than the competing crude oil derived products. In addition, the new compounds can be produced transparently as well as in a partially crystalline manner, which increases its later application possibilities using the same starting substance. Sieber explains: “By way of reaction conditions and catalysts during synthesis, we can easily control whether we will obtain a transparent or partially crystalline polyamide in the end. However, the basis for this is offered above all by the specific structure of the bio-based starting material which would be very expensive to obtain from fossil raw materials.”

Increasing sustainability

From an industrial point of view, it is important that the synthesis basically takes place in one reaction container. This “one-pot” process would not just allow a significant reduction in costs, but would also mean a clear increase in sustainability, according to Sieber.

The biogenic starting material (+)-3-carene can actually be distilled at a high purity and comparatively low cost from the turpentine oil produced as a secondary product in the cellulose industry. Up until now, the turpentine oil was only heated in the cellulose factories.

No competition with food production

Sieber points out that with turpentine oil being a side product of the forest industry, in contrary to the use of castor oil, we are not competing against food production. The researchers are not yet completely satisfied with the achieved overall yield of the process, this is at 25 percent by mass. Paul Stockmann, whose doctoral thesis at the TUM is based on the findings says: “Thanks to the simple scalability, the potential for an efficient process is very high.”

At the Fraunhofer IGB, the chemist is now working on establishing (+)-3-carene-based polyamides on the market as alternatives to crude-oil-based high-performance polyamides.

Source: jeccomposites.com

Picture: The two authors, Paul Stockmann and Dr. Daniel Van Opdenbosch, with the reactor in which the polymerizable monomer was produced from the natural product 3-carene.


Leggi anche

Un gruppo di ricercatori dell’Università del Queensland del Sud, sotto la guida del dottor Wahid Ferdous, sta studiando come sostituire le traverse ferroviarie in legno per i ponti con un nuovo materiale costituito da fibre composite e materiali di scarto. Il governo dello stato del Queensland e il produttore di traverse in cemento Austrak hanno finanziato il progetto attraverso una borsa di ricerca per l’industria….

Leggi tutto…

Analizzando le proprietà dei nuovi ritardanti di fiamma per materiali compositi, i ricercatori del laboratorio Advanced Fibers dell’Empa, centro svizzero per lo studio dei materiali avanzati, sotto la guida di Sabyasachi Gaan, hanno elaborato una tecnica che permette di rendere recuperabili le resine epossidiche, il cui limite di riutilizzo è intrinseco alla natura di materiali termoindurenti, ossia polimeri altamente reticolati che, una volta induriti, non possono essere sottoposti nuovamente a fusione senza carbonizzarsi….

Leggi tutto…

Refitech Composite Solutions innova i propri processi produttivi, installando una macchina CNC a cinque assi per la finitura di componenti compositi, che si aggiunge ai sistemi già operativi a tre assi. La nuova strumentazione consentirà di eseguire la lavorazione di forme 3D ancora più complesse in modo completamente automatico, ad alta velocità, garantendo una qualità elevata e una riproducibilità perfetta, in vista dei volumi di serie….

Leggi tutto…

Tim Young, Head of Sustainability del National Composites Centre, ha illustrato a “The Engineer” i risultati di una ricerca realizzata dall’istituto che fornisce una panoramica delle possibilità di introdurre soluzioni basate sulla chimica nella supply chain dei compositi nel Regno Unito, al fine di garantire la sostenibilità nel settore….

Leggi tutto…

Il National Composites Center (NCC) sta promuovendo un progetto industriale congiunto (JIP) che affronterà la sfida del benchmarking delle prestazioni di permeabilità dei tubi compositi termoplastici (TCP) per la distribuzione dell’idrogeno. L’obiettivo verrà raggiunto attraverso la produzione di campioni di tubi standardizzati, che costituiranno un database di misurazione della capacità del rivestimento e del materiale di rinforzo….

Leggi tutto…