Vulcanization of chlorobutyl rubber. I. The identification of crosslink precursors in compounds containing ZnO/ZnCl2

Characteristics and mechanism of low temperature dehydrochlorination of poly(vinyl chloride) in the presence of zinc(II) oxide

“…This result suggests that the activation energy of cross-linking dehydrochlorination is lowered in the presence of ZnO. Hendrikse et al [25,26] There have been many kinetic studies [1,4,11,22,24] for the dehydrochlorination of pure PVC, and the activation energy of the dehydrochlorination 1 is 109-134 kJ mol -1 .…”

Vulcanization of chlorobutyl rubber. III. Reaction mechanisms in compounds containing combinations of zinc dimethyldithiocarbamate, tetramethylthiuram disulfide, sulfur, and ZnO

“…7 It showed the endothermic melting of the calcium stearate stabilizer and an irregular, double peaked exotherm, starting at 138°C, earlier than in either of the above-mentioned ZnO/ZnCl 2 systems. As in ZnO/ZnCl 2 systems, 7,25 the shape of the exotherm is determined by the superimposition of an endotherm resulting from evaporation of volatiles (H 2 S and HSX) formed in the reactions discussed below.…”

“…7 TMTD (Flexsys, Brussels, Belgium), sulfur (AEC, Modderfontein, South Africa), and Zn 2 (dmtc) 4 (Bayer, Leverkusen, Germany).…”

“…7 Formulations quoted in brackets in the text are parts per hundred rubber. Compounds were vulcanized at a programmed heating rate in a differential scanning calorimeter (DSC) or isothermally in a press at 150°C.…”

“…ZnCl 2 , extracted from vulcanizates, was analyzed by atomic absorption spectroscopy. 7 In the Figures, the concentrations of reactants, intermediates, and products are expressed in terms of the initial mol concentrations of reactants, i.e., as the mol % of reactant remaining, or mol % intermediate/product formed from that reactant. The DSC cure curves (Fig.…”