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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - NanoTextSurf (Nanotextured surfaces for membranes, protective textiles, friction pads and abrasive materials)

Teaser

Summary

Cellulose nanomaterials produced either with chemical and/or mechanical means from cellulose fibres are safe, biodegradable, ultra-strong and durable. Cellulose nanomaterial are viscous dispersions and therefore it is necessary to modify application processes. The project approach is to construct nanostructured surfaces based on nanoscale biomaterials. The nanotextured products and their mechanically enhanced performance will be demonstrated in large scale as value added products. Sustainability assessment includes evaluations of their economic feasibility, safety and environmental acceptability. The results will be exploited in the existing manufacturing lines. This approach guarantees that robust, efficient and easily up-scalable pilot processes with in-line controlling methods will be available as open access services with reasonable costs. Hospital textiles, industrial wipes, air purification filters and food packaging materials are identified as other potential products.
The project results help to educate workforce, generate new jobs and secure production of such products in Europe. Technical and scientific findings of processability of the cellulose nanomaterials and product performance were presented in several internal workshops. Internal dissemination within the consortium supports training, knowledge transfer and educate workforce for future needs.
Main objectives are to develop the open access surface treatment pilot lines on industrially relevant scale and use them to demonstrate added value nanotextured products with improved mechanical properties (strength) and durability.

Work performed

Different nanocellulose grades: besides non-modified cellulose nanofibrils produced by mechanical means only and chemically modified cellulose nanofibrils produced on pilot scale, commercial cellulose nanocrystals and microfibrillated cellulose were used in different products.
Optimised formulations based on cellulose nanomaterials were studied for cast coated layers of industrial membranes and filter materials. Pre-treatments of industrial membranes and nanocellulose coating formulations were studied to ensure adequate adhesion between nanocellulose and substrate interface and high internal strength of the nanocellulose coating layers, both needed due to pressurized water flow in filtration. Additional anchoring polymer is needed to improve adhesion and durability of the membranes and therefore application basins were designed and executed in the surface treatment pilot machine. The internal surface of cellulose based non-woven fabrics were also modified with nanocelluloses with anionic or cationic functional groups. The antifouling capability of the coatings was determined with protein adhesion method in continuous flux conditions.
Different surfactants were studied to foam nanocelluloses and produce stable foams for the surface treatment of filter nonwovens on pilot scale. The effect on the bubble properties and the foam stability of nanocellulose foams were studied with different types of surfactants and different surfactant concentrations. Optimised foam formulations were applied on porous viscose substrates in laboratory scale. The water permeance as well as capture of metal ions was evaluated.
Nanocellulose based screen printing formulations were studied for textiles. Lean products were targeted by higher strength properties without impairing moisture control and breathability of the textiles with printed nanocellulose layer. Optimised formulation were trialled with different screens in screen printing pilot in order to study stability, product performance and durability of the printed textiles after washing cycles.
A nanocellulose-based formulation was applied with cast coating producing flexible materials with a stable friction with low vibrations and low wear, tested in laboratory and with high loading tests. The friction coefficient obtained was in the range of that required for friction paper used on multiple-disc clutches. A vacuum box was added to the surface treatment pilot line to enhance the adhesion and durability of novel flexible friction materials produced with cast coating application.
First approach for abrasive materials was to produce stable foams from nanocellulose suspensions containing abrasive particles and apply foam with a pilot foam coating applicator. Organic solvent free foam coating formulation were designed with water-based organic binders and small abrasive particles. The pilot foam coating application procedures were modified to improve the controllability of the foam application and adjustment of the nip with two rolls after the application. The second approach was to replace partially oil-based UV curable binder with nanocellulose to obtain higher mechanical durability and better thermal stability for the abrasive materials with screen printing technology. The stability of the printing pastes were tested with different screens to achieve the targeted dot size and good processability. The abrasive mixture was successfully printed on surface treated films on the screen printing pilot machine. The sanding tests were carried out to evaluate durability of abrasive materials.
Besides the product related modifications to the pilot machines, solutions for general challenges were studied. Drying of the cast coated nanocellulose layers is a major challenge and is studied in pilot scale in order to find efficient application and drying strategy without any defects. The in-line measuring technologies to measure film or coating layer thickness were also studied.
Four most potential demonstration ca

Final results

Fouling of membranes is one of the key cost parameters for membrane plants resulting costs related to needs of more frequent cleaning or replacement of the membranes. Hence, introducing low fouling membranes to customers will reduce their production costs significantly. The costs of friction materials will be reduced if the number of components can be reduced. Most of the industrial partners will buy nanocelluloses from a manufacturer rather than producing it themselves. Bio-based materials have a decreasing effect on environmental impacts because they are biodegradable and not only compostable, but they will degrade fast in nature. In friction and abrasive products, replacing partially or totally oil-based binders with nanocelluloses will lower the carbon footprint and improve thermal and mechanical strength of nanocellulose-based binders will increase the durability. All project partners expect improved performance for their existing products or completely new product lines as an outcome, thus giving them opportunity to enter new markets and increase their revenue. Globally production and operating costs are reduced in several industrial uses; not only in filtration, functional textiles, friction and abrasive materials but also in packaging materials, nonwovens for health care sector and in other industrial areas in the future.