Multifunctional organosilicon modifiers for bio-composite materials

Technological Overview

A Polish research organisation has developed a technology based on tailor-made organosilicon compounds acting as multifunctional modifiers for composite materials, in particular fibre-reinforced polymer composites.

The weak interface between the reinforcement and the polymer matrix is one of the main factors limiting the performance of composites, especially when hydrophilic natural or recycled fibres, such as cotton, flax or hemp, are combined with hydrophobic or biodegradable polymers. The developed organosilicon modifiers address this challenge by improving the compatibilisation of the matrix with the fibre, which enhances the stress transfer, the durability and the processability of the composite. Better fibre–matrix compatibility also allows a higher fibre content to be introduced into the composite, which, together with the improved interfacial adhesion, can significantly increase its mechanical properties.

The solution is based on a wide range of organosilicon compounds, including silanes, siloxanes, polysiloxanes, cyclosiloxanes and silsesquioxanes, as well as other functionalised organosilicon derivatives. The modifiers are synthesised from non-petrochemical raw materials in a highly efficient and scalable process. The type of organosilicon core and functional groups introduced into the molecule determines which property is enhanced and how well the modifier is compatible with a given fibre and polymer. The possibility of introducing different functional groups allows the same family of compounds to be used in different composite systems.

The modifiers can be used in three complementary ways:

•          as compatibilisers at the fibre–matrix interface, improving adhesion and dispersion of the fibre in the matrix;

•          as additives modifying the polymer matrix, improving selected mechanical, thermal, flame-retardant, adhesive or antibacterial properties, as well as resistance to moisture, UV and chemicals;

•          as agents for chemical modification of the fibre, providing additional functionalities such as hydrophobicity, flame retardancy or antibacterial activity.

Advantages and innovations

• improved compatibilisation between the polymer matrix and the fibre, particularly for hydrophilic natural and recycled fibres combined with hydrophobic or biodegradable polymers;

• possibility of increasing the fibre content in the composite while maintaining good dispersion and adhesion, leading to a significant improvement of mechanical properties;

• depending on its structure, a modifier can improve the fibre–matrix interface, enhance selected properties of the matrix and introduce additional functionalities to the fibre;

• tailor-made modifier structures adapted to the type of fibre, polymer matrix and required properties;

• enhancement of composite material properties, including mechanical, thermal, flame-retardant and antibacterial properties and resistance to moisture, UV and chemicals

• wide range of applicable organosilicon compounds: silanes, siloxanes, polysiloxanes, cyclosiloxanes, silsesquioxanes and other functionalised organosilicon derivatives;

• possibility to use fibres from textile waste streams, supporting valorisation of waste and circular economy;

• suitability for biodegradable and bio-based composites, supporting safe-and-sustainable-by-design material development;

• synthesis from non-petrochemical raw materials;

• highly efficient and scalable synthesis process, with the possibility to produce modifiers in batches of up to 100 kg;

• suitability for further laboratory and pilot-scale validation and technology transfer towards industrial applications.

Collaboration

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