Project: Novel, breathable membranes based on elastomers and renewable biomaterials such as cellulose and lignin

The overall goal of the project is to develop superior breathable, water-repellant membranes of the GoreTex type for textiles, shoes and gloves including protective ABC clothing for civil use (e.g. fire fighters). Use of fluoropolymers shall be avoided due to negative environmental impact. Instead, these membranes shall be based on benign rubbers (such as silicone or thermoplastic elastomer, TPE. Various performance needs are met by integrating nano-size fillers such as renewable cellulose and lignin as well as carbon nano tubes for special applications (e.g. fire fighters clothing). These nano-sized fillers are essential for the function of the membranes, but need to be chemically modified. Preparation of nano-fillers and prototype testing are the major work packages in the project._x000D__x000D_Membranes available today have the following shortcomings: (i) the typically used fluoropolymers are non-biodegradable and generate fluorinated organic compounds during incineration, (ii) properties are unsatisfactory especially in the professional area, (iii) materials are expensive and difficult to process, (iv) repeated cleaning is difficult or sometimes impossible._x000D__x000D_The project leader, SiOx, has developed methods to make cellulose and lignin compatible to a range of plastics, using inexpensive treatment in high pressure CO2 reactors. The method allows either the coating of cellulose / lignin with thermoplastics such as polystyrene or synthetic rubber, alternatively it allows the chemical derivatisation using chemicals with anhydride or similar (ester forming) functionality. It is proven at laboratory scale that the method affords cellulose/lignin which is highly compatible with plastics and leather and furthermore has a strong re-inforcing effect._x000D__x000D_The project P, W+R GmbH is a producer of gloves for advanced applications, such as sports and leisure, fire fighting, protective clothing for industry, law enforcement and the like. W+R GmbH holds patent applications regarding novel breathable membranes (see below) which are intended for mass as well as specialized markets. For both markets, cellulose and lignin are interesting materials due to their absorption capabilities and mechanical properties as reinforcement._x000D__x000D_W+R and Siox have jointly invented novel membranes and filed provisional patent applications. The basic concept is to provide an elastomer filled with a CO2 soluble oil which can be removed after the polymerization of the membrane film. This is done using in an environmentally friendly manner using liquid CO2. Such membranes have been prepared and tested in cooperation with e.g. Wacker Chemicals. It was found that the elastic network with artificial pores (sites from which oil has been removed) collapses unless it is stabilized by rigid filling elements. Our pre-studies proved that modified cellulose and modified lignin are such suitable elements which - like a rigid skeleton - can prevent the collapse of membranes. It appears that chemical modification is necessary to disperse cellulose and lignin on nano level. Only in these membranes elasticity, gas permeability and resistance to liquid water etc could be adjusted to target level. A range of practical problems has to be solved (see risk section), but the positive laboratory results suggest strongly that the target of developing superior breathable membranes on the basis of benign and partly renewable polymers is highly realistic and achievable._x000D__x000D_The project is divided in a number of work packages. These reflect partly the normal assessment sequence of new product opportunities, i.e. literature screening, laboratory trials, economic and technical feasibility studies of increasing complexity, cross-checks using customer trials, patenting efforts and development of marketing and sales concepts. The work packages also relate to different clothing product lines (jackets, gloves, leather) which shall be brought to prototype level during the project._x000D__x000D_In summary, the product which will be developed is a novel class of breathable membranes for clothing. These membranes are based on silicone or TPE (thermoplastic elastomer) rubber, and contain COly functionalised cellulose and lignin as reinforcing components. _x000D__x000D_The project Ps have a network of end-users today which request the above mentioned products (e.g. gloves for rescue teams), and experience suggests that an ambitious project like this should have clearly identified end uses with clear specifications to be met._x000D_Below, detailed background will be given describing the state-of-the-art, the experience and capabilities of the project Ps, the methods by which the product development will be pursued, the required R&D services, and the expected financial impact.

Acronym Cell-Lig-Membranes (Reference Number: 5176)
Duration 01/01/2010 - 31/12/2013
Project Topic The goal is to develop improved garment membranes (Gore-Tex type) based on silicone or TPE rubber and nanofillers such as modified cellulose and lignin. Production methods are less costly, fluoropolymers are avoided and life cycle expands because products sustain repeated washing cycles.
Project Results
(after finalisation)
a) detailed knowledge of the requirements regarding functionality, pricing and performance for a breathable environmentally friendly membrane_x000D_b) 3-dimensional membranes can be produced with dipping technology
Network Eurostars
Call Eurostars Cut-Off 3

Project partner

Number Name Role Country
2 W+R GmbH Partner Germany
2 SiOx Machines AB Coordinator Sweden