Poly(furfuryl alcohol) with different amounts of oxymethylenic bridges was synthesized using trifluoroacetic and p-toluenesulfonic acid. All polymers displayed a tendency to retain acids. The isolated products containing traces of acid became insoluble in a few hours; while neutral material maintains their solubility for at least one month. Polymers stored in solution were stable according to their ¹H NMR spectra. Polymers cross-linked after being exposed to UV radiation. The product of the reaction of polymer with maleic anhydride is useful for preparing negative photoresists.

Propriedades termofísicas de copolímeros poli(3-hidroxibutirato-co-3-hidroxivalerato) poli(3HB-co-3HV) foram investigadas com o objetivo de entender a influência das unidades monoméricas de 3-hidroxivalerato (3HV) incorporadas durante a copolimerização aleatória. Os resultados mostram forte evidência de que uma plastificação interna é introduzida no copolímero pelas unidades de 3HV. Foi observado que a condutividade térmica do copolímero aumentou linearmente com a concentração de 3HV. Por outro lado, a difusividade térmica foi muito sensível as mudanças de composição do copolímero, apresentou um aumento brusco inicial e atingiu um platô de saturação. Os gráficos de amplitude contra frequência indicam a predominância de um mecanismo termoelástico. Neste trabalho é apresentando uma nova montagem fotoacústica para as medidas de efusividade térmica.

Basic data on thermophysical properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymers poly(3HB-co-3HV) were investigated with the aim of understanding the role of 3-hydroxyvalerate monomeric units (3HV) incorporated during random copolymerization. The results show strong evidence that internal plastification is produced by the introduction of 3HV units in the copolymer. It was observed that copolymer thermal conductivity increased approximately linearly with the 3HV content. On the other hand, thermal diffusivity was very sensitive to the change in the copolymer composition showing a sudden rise that attained a saturation plateau. Amplitude-frequency plots indicate that a thermoelastic bending mechanism is operating. In this paper a new photoacoustic arrangement for the measurement of thermal effusivity is presented.

The inhibited radical polymerization of vinyl acetate initiated by 2,2-azobisisobutyronitrile was studied in the presence of some furan derivatives bearing a double bond on the side group. The modelling of such systems has permitted to estimate the values of the kinetic parameters for these inhibitors. A sensitivity analysis was performed to obtain a better insight into the mechanism; it appears that macroradical degradative transfer reaction to furan compounds is the most important reaction in comparison with propagation or primary radical degradative transfer.

Some furan compounds bearing a double bond in the side group have been examined as inhibitors of the radical polymerization of vinyl acetate initiated by AIBN in ethyl acetate at 60 ºC. The inhibition effect was found to follow the order: furfurylidenacetone > furylacrolein > furanacrylic acid > furylacrylmorpholinamide as a consequence of the greater stabilization of the radical formed. The site of radical attack can be considered either as the C-5 position of the furan ring or as the double bond of the side group. The compounds taken as models such as 5-methylfuranacrylic acid and furfurylidenbutanal indicate that both positions can participate in the inhibitory process.