Chemiluminescence from paper: II. The effect of sample crystallinity, morphology and size

Sample properties, such as crystallinity, morphology and size, potentially influencing chemiluminescence emission during atmospheric oxidation of cellulose, were studied. In order to obtain samples with 30.7, 26.4, 14.6, and 0.0% crystallinity, microcrystalline cellulose was milled to different extents. It was shown that crystallinity has no major influence on chemiluminescence emissions either as a result of thermal or photo-oxidation. Pulp beating to different degrees was used to obtain pulp fibres of different morphology and thus different surfaces exposed to atmospheric oxygen. It was determined that the more refined the fibres, the larger is the content of peroxides present in the material. As a consequence, higher chemiluminescence emissions were observed. With the aim of sample miniaturisation samples of 0.11, 0.21, 0.47 and 0.70 mm were compared with the usual sample size of 9 mm diameter. The minimum sample diameter giving a satisfactory signal was 0.47 mm.