The effect of melting conditions on the iPB-1 structure and the II → I phase transformation rate

The effect of long-term natural aging on the iPB-1 structure and the II – I phase transformation rate

“…In our previous analysis [32] , we found a slightly accelerating effect of 101x re-melting of the same sample on the II → I phase transformation rate compared to the once-melted, non-aged samples of homopolymers PB 0110, PB 0300, and DP 0400 (2, 7, and 8 h acceleration, respectively). In the study of the effect of natural aging on the phase transformation, the following different results were obtained for samples melted two and three times, which clearly points to the effect of aging time.…”

“…The time of polymer sample aging was calculated from the moment of our first melting of commercially purchased polymer granules. Based on previous results [32] , a standard melting procedure consisting of 5 min heating at 160°C was chosen. After first melting and cooling, samples were aged in the darkness to avoid the effect of light or UV radiation.…”

“…Each spectrum was normalized on sample film thickness. For IR analysis, typical polyethylene -CH 2bending deformation bands at 1473 and 1463 cm -1 [32,33] and polybutene-1 -CH 3 wagging spectral bands at 1380.5 and 1364.6 cm -1 [28] , were used. The intensity ratio of spectral bands at 2965 cm -1 (methyl groups) to 2928 cm -1 (methylene groups) wavelengths was used as a measure of the polymer short chain branching, representing the ratio of methyl/methylene functional groups.…”