The solution and dispersion characteristics of several hydrophobic derivatives of cellulose have been studied and the abilities of these polymers to afford effective end grain sealing of Corsican pine have been examined. Both solution and dispersion treatments with ethyl cellulose imparted good water repellency and end grain sealing to wood samples, however, the disperse systems possessed lower viscosities. Scanning Electron Microscopy (SEM) of treated samples and polymer radiolabelling/autoradiography studies indicated pit-membrane pore filtration of polymer particles close to the end grain. A range of esters (C2-C18 side chains) of Hydroxypropyl Cellulose have been prepared and characterised (FTIR, NMR). The acetyl, propyl and butyl esters formed coherent, flexible films. The C6, C9, C10 and C11 esters were essentially gums. However, the C18 (stearoyl) ester was found to form strong, wax like films, due to pronounced ester side-chain interactions. A number of the polymers were applied to Corsican pine test samples. Water repellent ability was found to strongly parallel the ability of the derivatives to form coherent polymer films. The C18 (stearoyl) ester exhibited impressive end grain sealing; outperforming all other systems tested at equivalent application levels. This work indicates that hydrophobic polymers that readily form strong films from solution or dispersion afford enhanced end grain sealing as compared to materials that simply produce a hydrophobic effect.

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