Polychloroalicyclic Ketones as Promoters for Crosslinking Polymers

Abstract

Abstract Polychloroalicyclic ketones are chlorine liberating compounds which in combination with activators and coagents promote crosslinking of saturated and unsaturated polymers. One of the most active ketone is octachloro-3-cyclohexen-l-one (OCTA). During the curing process the alicyclic ketones transform into phenols and probably some phenates. The most effective activators are magnesium and calcium hydroxides and oxides. These curing systems are also activated by acidic and basic fillers. Active coagents are sulfur, p-benzoquinones and maleimides. EPM of superior thermal stability is obtained with the chlorinated p-benzoquinones as the coagent. The apparent order of crosslink formation in EPM using these curing systems is pseudo first order. In case of OCTA/MgO/coagent system, the specific rate of crosslink formation is directly proportional to (MgO)1/2/(OCTA) and the maximum crosslinks formed vary linearly with (MgO)1/2/(OCTA). The OCTA system is most suitable for curing saturated polymers or their blends, and not for black stocks of high unsaturation polymers because of its high reactivity. Saturated polymers may be heated with OCTA and MgO and modified to unsaturated polymers which are curable by the conventional sulfur-accelerator system.