Microencapsulation is a versatile technology that enables the development of innovative and value-added products with enhanced properties and consumer benefits. It is a technique that encloses tiny particles, droplets, or substances within a polymeric shell or coating. These microcapsules can range in size from a few micrometres to a few millimetres.
Microencapsulation is often used to control the release of substances within plastics. Possible applications include the encapsulation of reactive components such as catalysts and initiators, polymer additives such as flame retardants and pigments, or cosmetic ingredients, food additives, flavours, and fragrances. In the manufacturing of fragranced plastic products, for example, microencapsulated perfume can slowly release its scent over time, providing a longer-lasting effect.
Germany’s Fraunhofer Institute for Applied Polymer Research (IAP) has been working on the technology for the past 30 years. The Fraunhofer Technology Platform Microencapsulation, established in 2009, organises a workshop on selected topics every two years. Bioplastics are the topic of choice for this year’s workshop, taking place on November 16 in Potsdam, Germany.
Fraunhofer uses biopolymers like cellulose and starch derivatives for the synthesis of customised microencapsulated additives and active ingredients. It also deploys synthetic polymers like amnio resin, polyurethane, and polyamide, but the focus is now on bioplastics to ensure manufactures get their products approved under the EU law on Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH).
New regulations in the European Union will prohibit the sale of products that contain intentionally added conventional microplastics which are released during use. Transitional periods of four to 12 years apply to applications in cosmetics, fertilizers, as well as detergents and cleaning agents. Fraunhofer believes that natural materials and biodegradable polymers are key in protecting products from being subject to such regulations.
"We are developing biodegradable microcapsules that are functional and cost-effective," said Dr. Alexandra Latnikova, an expert in microencapsulation at Fraunhofer IAP. A deep understanding of polymer and particle formation processes is essential for success, Latnikova added. The desired functionality of microcapsules is often is tension with requirements for rapid biodegradability in many applications, she explained in a statement. Parameters such as availability, stable quality, price, and sustainable sourcing of capsule wall materials also determine the basis for environmentally friendly microcapsules.
"All these parameters must be met to obtain solutions with high market potential. In recent years, we have seen a great interest in chemically cross-linkable, water-soluble polymers. These polymers save the use of solvents and avoid new investments, as it allows to use existing equipment. Water-soluble cellulose sulphate and aqueous nano cellulose dispersions are good examples," adds Dr. Latnikova.
Fraunhofer IAP’s workshop will present new developments in microencapsulation with natural and biodegradable materials. The institute invites participants to discuss possible solutions in an open forum.