Rheometrical studies on the process of polyethylene and ethylene copolymers cross-linking
in the presence of peroxides. Part I. Elaboration of the methodology of investigations
Polimery 2003, No 10, 709
Possibility of applying of a rheometer „Wulkametr WG-93” (produced by „Metalchem”, Gliwice, Poland, Fig. 1), widely used for rubber curing course estimation, to checking of PE-LD crosslinking process was studied. Three various stabilized compositions of PE-LD and dicumyl peroxide (Table 1) were prepared and crosslinked in the vulcameter, at isothermal conditions at 170, 180 or 200 °C. On the basis of curves of torque moment (M) versus time (t) dependences, the following characteristic parameters of crosslinking process (Fig. 2) have been determined: minimal and maximal M value, initiation time of crosslinking and time of maximal M. Very good repeatability of M = f(t) dependence at constant temperature (Fig. 3) has been found. Relative standard deviations of characteristic parameters of PE-LD crosslinking process are placed in the range from 2.5 to 7.1% of average values determined from 10 measures (Tables 2—4). The results obtained show that „Wulkametr WG-93” (after slight modification) and the method described can be used for polyethylene crosslinking process checking so wider than original purpose of the apparatus.
Keywords: polyethylene, crosslinking, measure in a vulcameter