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Kinetics and mechanisms of thermal imidization in solution and solid state were studied by UV-visible, fluorescence, FTIR, and size-exclusion chromatography, using polyamic acid synthesized from 1,5-diaminonaphthalene (DAN) and a partially fluorinated dianhydride (6FDA). Since all other reaction intermediates have negligible fluorescence, fluorescence spectroscopy was used to measure the concentration of DAN due to depolymerization from poly(amic acid), which was confirmed by size-exclusion chromatog raphy. Deconvolution of UV-visible spectra using model compound spectra provided compositional analysis of involved species from which the rate constants were extracted. In dilute solution imidization, the depolymerization rate was -3 times greater than that of imidization, with activation energies of approximately 15 kcal/mol. In a thin film imidized between 150 and 180 "C, much less depolymerization was observed, with the imidization rate slightly faster and activation energy greater than the corresponding parameters in dilute solution. FTIR results provided independent confirmation of the compositional analysis estimated by UVvisible spectral deconvolution.

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Over a number of years we have been investigating ways in which e‐communication can contribute to children's writing development and how new technology re‐frames our understandings of writing in the classroom (Merchant, 2003; Burnett et al, 2004; Burnett et al, 2005; Merchant, 2005). Here we analyse the digital writing of pupils from two linked primary school classes (Year 3–5) in the North of England. Part of the project involved the pupils in communicating about themselves and their interests to email partners of the same age. In this article, we track children's identity performance in informal message exchange and show how this contributed to a final knowledge product. We explore how work that had its origins in representing children's lives and identities reflected their position in wider cultural worlds. This perspective causes us to question whether there are there sufficient opportunities for pupils to explore and express ‘who they are’ in the current content‐driven curriculum where public genres are central and personal voice is peripheral.