Maryvonne Brigodiot

Lipozyme-catalyzed transesterification of oligo(methylacrylate)s

SummaryOligo(methylacrylate)s with ester end-group are transesterified by allyl alcohol in the presence of lipozyme as catalyst. The transesterification is regioselective: only end-group is modified. The structure of the modified oligomers is studied by 13C NMR spectroscopy.

Enzyme-catalyzed hydrolysis of unsaturated polyester networks. II. Enzyme-catalyzed hydrolysis of polyester networks prepared from poly(1,2-propanediyl fumarate)

The results obtained in Part I relative to the enzyme-catalyzed hydrolysis of poly(1,2-propanediyl fumarate) are applied to the hydrolysis of the networks prepared from this polyester. The weight loss of polyester samples after 14 days of hydrolysis was correlated to the degree of crosslinking (α) determined by differential scanning calorimetry (DSC). In this work, it was shown that the enzyme-catalyzed hydrolysis rapidly takes place on the uncrosslinked polyester chains only, whereas the chemical hydrolysis affected both free and crosslinked chains. The initial hydrolysis rate of the chemical process does not depend on α or on the nature of the chains (free or crosslinked) but it is lower than that of the enzymatic process.

Attribution comparee des spectres de vibrations de quelques derives de l'anthracene substitues en 9 et en 9,10—I: Region 100–650 cm−1

Abstract The infrared and Raman spectra of 9-monosubstituted and 9–10 disubstituted anthracenes (C 14 H 8 Y 2 ) in the solid state and in solution have been investigated. An assignment of the observed bands is given and the fundamentals are compared with those of the 1,2 disubstituted benzenes.

Chemical modification of chlorinated rubbers—III. Quantitative study of the grafting of chlorinated rubber by aminoesters and versamids

Abstract A quantitative study of the grafting of chlorinated rubber by ethyl 11-aminoundecanoate is carried out. A self-condensation of the aminoester takes place during the grafting; its extent is determined. The grafting of CR by versamid 100 (acetylated or not) is studied quantitatively by several analytical methods (i.r., 1H- and 13C-NMR) and they are compared with respect to accuracy. Non-crosslinked versamid-grafted-chlorinated rubber is obtained.