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Cellulose fiber waste from the white cellulose pulp purification process produced by the company Nipo Cellulose-Brazil (CENIBRA) was used in the preparation of composites with polyurethane. An elastomeric polyurethane based on polyether poly(tetramethylene glycol) and 4,4-diphenylmethane diisocyanate was used as polymeric matrix. Structural, thermal, and morphological characterization of the composites was carried out by infrared spectroscopy, thermogravimetry, differential scanning calorimetry, and scanning electron microscopy. The results indicate that interfacial interaction between the cellulose fiber residue and the polyurethane matrix occurs and that cellulose waste is a promising reinforcement for polyurethane composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 336–340, 2005

Rigid polyurethane composite foams were prepared with cellulose fibers as a filler. The cellulose fibers were an industrial residue of blanched cellulose pulp production. The influence of the cellulose fiber concentration on the structural, thermal, mechanical, and morphological properties of the foams was investigated. We also studied the influence of the cellulose fibers on the foam's resistance to fungal attack by placing a suspension of known fungus in contact with the surface of the foam and following the morphological evolution as a function of time (for 60 days). The increase in the cellulose filler concentration in the foams, up to 16% w/w with respect to the polyol, changed their properties as follows: (1) the cell size decreased, (2) the thermooxidative stability and mechanical properties remained approximately constant, (3) the thermal conductivity decreased slightly, and (4) fungal growth was observed. Therefore, a cellulosic fibrous industrial residue was rationally valorized as a filler in classical rigid polyurethane foams; this yielded materials with mechanical resistance and a susceptibility to fungi in a wet environment. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010