**2.5 Determination of maleic anhydride (MAH) in polypropylenes and ethylene-butyl acrylate (EBA) copolymers to establish the relationship between free and grafted MAH in the polymeric matrix**

Two samples of homopolymer polypropylene and three EBA samples were analyzed by TD-GC/MS and Py-GC/MS. These are two base resins that have been subjected to grafting processes with MAH at theoretical contents of around 1%. The samples have been analyzed with two different methodologies:


With the first methodology the chromatograms that were obtained showed peaks corresponding to the presence of MAH. However, the sum of the two obtained signals is adjusted to MAH contents two orders of magnitude lower than the MAH used in the preparation of the samples, consequently, the MAH detected in the two cases must be assigned to the free MAH. So, the MAH that was detected in the analysis at 320°C cannot be consider as grafted MAH.

The tests carried out by pyrolysis (see **Figure 12**) show a single MAH signal per sample, this leads to think that the grafted MAH has not been detected as such. As it is part of the polymer chain, the MAH is incorporated by the double bond of its molecule, that is, as succinic anhydride units (**Figure 13**), pyrolysis does not make the grafting on

**Figure 12.** *Py-GC/MS (pyrolysis temperature of 850°C) of one of the grafted EBA samples.*

*Pyrolysis-GC/MS, A Powerful Analytical Tool for Additives and Polymers Characterization DOI: http://dx.doi.org/10.5772/intechopen.101623*

**Figure 13.** *Incorporation of MAH in the polymer.*

the polymer reversible, derivatives of polymeric matrix and succinic anhydride are generated, which makes it impossible to directly estimate the fraction of MAH grafted.

Non-destructive spectroscopic (IR, NMR) techniques are recommended for this purpose.
