熱分解ガスクロマトグラフィーによる加硫EPDMゴムの硫黄架橋部の構造解析

抄録

Sulfur-bridge structures in vulcanizates of EPDM rubber cured with sulfur tagged accelerators as 2-mercaptoben-zotiazole (MBT), tetramethylthiuram-monosulfide (TMTM) and tetramethylthiuram-disulfide (TMTD) were studied by pyrolysis gas chromatography (Py-GC) with a sulfur selective flame photometric detector(FPD). Two kinds of sulfur containing products such as C₇H₆S(I)(II) were typically observed on the pyrolysis gas chromatogram(pyrogtoram). These products might be assigned for 2, 4-cyclopenta[2, 3-b]thiophene and 2, 5-cyclopenta[2, 3-b]thiophene and supposed to be formed from sulfur bridges to ethylidene-norbornene residues in the polymer chain through cyclization. The vulcanization process for EPDM rubbers was discussed on the basis of relationships between the relative yield of C₇H₆S(I) (II) and curing times. The chemical mechanisms of formation of sulfur-bridges were also discussed on the basis of the observed pyrograms at the beginning of curing times.