Véronique Carlier

The anhydride content of some commercial PP-g-MA: FTIR and titration

A set of anhydride-grafted polypropylenes was collected from various companies. They were studied in light of our recent results on polypropylene melt grafted with maleic anhydride.(1) This work confirmed that an important decrease of the anhydride content is recorded on heating or washing, due to the elimination of free, ungrafted products, respectively, by sublimation of maleic anhydride and by polymaleic anhydride solubilization. The deconvolution of the infrared spectra of washed anhydride-grafted polypropylenes (PP-g-MA) revealed two types of grafted anhydride: succinic anhydride form and polymaleic anhydride form. All in all, four forms of anhydride functions were detected: two grafted and two free, each being either on monomeric or polymeric forms. Nevertheless, one PP-g-MA (Hercoprime) can be distinguished by its very high grafting level. This polymer is therefore discussed in more detail. Finally, all the present results are discussed with regard to the principal applications of the PP-g-MA as a blend compatiblizer or as an adhesion promoter

Sizing Removal and Functionalization of the Carbon-fiber Surface Studied By Combined Tof Sims and Xps

Time-of-flight secondary ion mass spectrometry (TOF SIMS) and X-ray photoelectron spectroscopy (XPS) have been jointly used to study a two-step surface processing of AS4 carbon fiber: extraction of sizing in CH2Cl2 and functionalization with trimellitic anhydride. The combined information on molecular specificity obtained with TOF SIMS and quantification obtained with XPS allows us to follow qualitatively and quantitatively the changes in functional groups on the carbon surface. The results show that the sizing on AS4 contains at least four different compounds. These compounds can be extracted in CH2Cl2 and the elimination is almost complete for silicone. The functionalization of AS4 with trimellitic anhydride has been realized. The reaction takes place between the amine groups on the carbon fiber and the two types of functional groups in trimellitic anhydride.

Reactivity between carbon fibres and anhydride. A study by radiochemical titration and ToF-SIMS analysis

This paper deals with the radiochemical titration of carbon fibres (ex-PAN AS4 from Hercules) with C-14 labelled succinic anhydride in view of quantifying the reactivity between anhydride groups and the functionalities (amine, hydroxyl, etc.) of C fibres. A transesterification reaction due to the chemical labelling procedure is observed and is confirmed by time-of-flight secondary ion mass spectrometry (ToF-SIMS) analyses. It is finally used for discriminating between the reactivity of anhydride towards amino groups and other fibre functionalities