Broad line NMR studies of linear and branched polyethylene

✍ Scribed by S. Rafi Ahmad; A. Charlesby

• Publisher: Elsevier Science
• Year: 1975
• Tongue: English
• Weight: 218 KB
• Volume: 11
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(75)90180-9

✦ Synopsis

Temperature dependence of the shape and iinewidth of the broad-line NMR spectra of commercially available high-density polyethylene (PE/HD), low-density polyethylene (PE/LD with ~ 3 per cent CH3), block-.copolythene (PE/AA with ~ 3 per cent acrylic acid) and polyethylene single crystal (PE' SC) were investigated to obtain information on the effect of branching and structural changes on the glasstransition temperature (To) and activation energy of molecular motion (E). The relatively lower value of TO "--100 ~ for PE/HD compared to TO = -85 ~ and -60 ° for PE/CH 3 and PE/AA. along with the estimated lower value ore "-2.1 keal/mole for PE/H D compared to 2.6 and 5'1 kcal/mole for PE/CH3 and PE/AA, respectively, were interpreted by a molecular reorientational process connected mainly with the sidegroups of the main polymeric chains.