Surface-initiated ring-opening metathesis polymerisation from cellulose fibres

Abstract

In this study, cellulose fibres have been grafted utilizing surface-initiated ring-opening metathesis polymerisation (SI-ROMP). Initially, a Grubbs' type catalyst was immobilized onto filter paper whereafter SI-ROMP of norbornene was performed from the surface of the fibres at three different reaction temperatures, room temperature (RT), 0 °C and −18 °C, and for different reaction times. The evaluation of the grafted cellulose was performed by contact angle measurements, FT-Raman spectroscopy, FE-SEM and TGA. After the grafting, all samples were clearly hydrophobic with weight increases up to over 100%. The FT-Raman spectroscopy analysis showed significant structural changes after polymerization for cellulose substrates polymerized at 0 °C and RT, confirming that a polymer was grafted from the surface. FE-SEM images verified that these samples are covered by polynorbornene and that the fibrillar structure of the native cellulose disappeared. For the samples grafted at −18 °C, no significant changes were seen with these analysis methods. However, SI-ROMP appears to be a versatile method to modify cellulose fibres.