Photo-induced scission and crosslinking in LDPE, LLDPE, and HDPE

Macromolecular scission and crosslinking rate changes during polyolefin photo-oxidation

“…Data points in the graphs presented in Section 4 are plotted at the midpoint of the layer removed (e.g., the results for material removed when lowering the surface from 0.4 mm below the original (exposed) surface to 0.5 mm depth are plotted at 0.45 mm depth). The GPC analyses were conducted at Rapra Technology Ltd. (Shawbury, Shrewsbury, UK) using their standard procedures [7,14].…”

Evaluation of poly(ethylene terephthalate) photostabilisation using FTIR spectrometry of evolved carbon dioxide

“…Oxygen diffusionlimited reaction is caused when the oxygen from the atmosphere is consumed by rapid reaction near the illuminated surface before it can diffuse into the interior to react there. It is quite common in photo-oxidation of polymers and has been widely observed in polyolefins [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. However, oxygen starvation is expected to occur at even smaller depths in PET than in polyolefins because the diffusion coefficient for oxygen in PET is two orders of magnitude smaller than for PE [32].…”

Installation of a reactive site for covalent wiring onto an intrinsically conductive poly(ionic liquid)

“…The increase in terminal thiophene rings implies a reduction in chain length possibly arising from chain scission as a result of bromination. Polymer oxidation has been known to lead to chain scission [40]. A reduction in thiophene backbone conjugation, which could also arise from backbone conformational changes, is also indicated by an increase in the intensity ratio between the symmetric (1462 cm À1 ) and antisymmetric (1497 cm À1 ) C a = C b thienylene stretches compared to the non-brominated polymer [41].…”