SynopsisCellulose fractions of different molecular weights were subjected to dynamic thermogravimetric analysis in a nitrogen atmosphere. From the experimental data, activation energies and reaction orders were obtained following the Freeman-Carroll and Broido methods. The thermal stabilities of the samples were estimated taking into account the values of T,, T,,,, and E,. The results show that thermal stability increases as the molecular weight increases. It was also found that the cellulose pyrolisis process cannot be described as having a single value of E, over the entire pyrolisis range. The dependence of E, on molecular weight is also discussed.

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A commercial polyarylate (PAr), a copolyester of Bisphenol‐A with 50 percent terephthalate‐50 percent isophthalate, has been characterized by means of a combination of gel permeation chromatography and viscometry. It has been studied as first component of a series of polymer blends. The presence of either one glass transition temperature (Tg) or two has been used as a criterion to determine the miscibility of each blend. In some cases, the possible incidence of transesterification reactions has been considered.