Analysis MethodAnalysis of 5-ethylidene-2-norbornene in ethylene-propylene-diene terpolymer using pyrolysis-GC/MS

Ethylene-propylene-diene terpolymer (EPDM) having 5-ethylidene-2-norbornene (ENB) as a diene unit was pyrolyzed and the pyrolysis products were analyzed using gas chromatography/mass spectrometry (GC/MS) to develop a method for identification and quantitation of ENB. Pyrolysis products formed from ENB units were determined by comparing pyrolysis products of EPDMs with different ENB contents. Principal pyrolysis products generated from ENB units were benzene, toluene and 4-ethylidene-1-cyclopentene. Relative peak intensities of benzene and toluene increased as the pyrolysis temperature increased, whereas that of 4-ethylidene-1-cyclopentene decreased. The differences in peak intensity ratios of the ENB-derived pyrolysis products/propylene between EPDM and EPM (ENB content = 0 wt%) linearly increased as the ENB content of EPDM increased. ENB content in EPDM can be determined using the linear relationship between the difference in the peak intensity ratios and the ENB content.