1. CNF in papermaking: influence on the wet-web resistance and handsheets properties using PCC as filler Tiago F. Nunes, Ana F. Lourenço, José A. F. Gamelas, Paulo J. Ferreira 26 th and 27 th May 2015 San Sebastian, Spain

2. CNF production and characterization 2 COST ACTION FP1105 San Sebastian 26 TH and 27 TH May 2015 Chemical treatment - E. globulus kraft pulp [1% (w/w)] -TEMPO (0,016 g/g) -NaClO (5 and 11 mmol/g of pulp) -NaBr (0,1 g/g) -NaOH (for pH control) - E. globulus kraft pulp [1% (w/w)] -TEMPO (0,016 g/g) -NaClO (5 and 11 mmol/g of pulp) -NaBr (0,1 g/g) -NaOH (for pH control) Mechanical treatment (homogenizer) Final product Characterization  Yield (gravimetric analysis)  Concentration of carboxylic groups (conductometric titration) Sample Yield, % Carboxylic groups, mmol/g CNF 5910,69 CNF 11971,78

3. Lab handsheets production and characterization 3 - Refined E. globulus kraft pulp (36ºSR) - CNF (3%, w/w) - PCC (20% and 30%, w/w) - Starch (1%, w/w) - ASA (0,12%, w/w) - C-PAM (0,02%, w/w) - Refined E. globulus kraft pulp (36ºSR) - CNF (3%, w/w) - PCC (20% and 30%, w/w) - Starch (1%, w/w) - ASA (0,12%, w/w) - C-PAM (0,02%, w/w) mix during 5 minutes Handsheets formation  Drainage time  Basis weight  Filler retention  Tensile strength  Air resistance (Gurley)  Wet-web resistance  Porosity of handsheets Characterization Sample: 30% PCC + Drainability, s Basis weight, g/m 2 Filler Retention, % Tensile Index, N.m/g Air Resistance (Gurley), s/100 ml –7,681,885,823,04,0 3% CNF 517,582,990,931,121,6 3% CNF 116,563,841,031,43,6 COST ACTION FP1105 San Sebastian 26 TH and 27 TH May 2015

4. Handsheets Porosity 4 COST ACTION FP1105 San Sebastian 26 TH and 27 TH May 2015 CNF 11 CNF 5 Total porosity: 58,57 % Total porosity: 57,03 % The total porosity of both handsheets (with CNF 5 and CNF 11) is practically the same, which in principle is contrary to the results of the air resistance However, the handsheets produced with the smaller CNF (11 mmol/g) have much more larger pores, contributing therefore to the more reduced air resistance

5. Bonding mechanism CNF acts as flocculant of the PCC particles by the patching mechanism C-PAM acts as retention agent of the PCC agglomerates 5 COST ACTION FP1105 San Sebastian 26 TH and 27 TH May 2015

6. Wet-web resistance The addition of CNF 5 increases the tensile index for moisture values below 60% In terms of the paper machine runnability, for moisture contents common in the drying section, the use of CNF may contribute, through the higher wet-web tensile resistance, to less breaks and to higher operating machine speeds 6 COST ACTION FP1105 San Sebastian 26 TH and 27 TH May 2015

7. 7 Thank you for your attention! The authors acknowledge QREN (Quadro de Referência Estratégico Nacional) for financial support (QREN 34169 NMC) and RAIZ (Instituto de Investigação da Floresta e do Papel) for the laboratory facilities and some furnish components.