Sizes of long-chain branches in a high-pressure low-density polyethylene as a function of molecular weight

✍ Scribed by Takao Usami; Yukitaka Gotoh; Sigeru Takayama

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 307 KB
• Volume: 43
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1991.070431009

✦ Synopsis

SYNOPSIS

The mean length and the indices of long-chain branches (LCBs) of a high-pressure lowdensity polyethylene (HPLDPE) as a function of molecular weight have been determined for its molecular-weight-fractionated parts by the I3C-NMR analysis and the viscosity measurements. The mean LCB length of the fractions was of the order of 200-300 carbons in length. The size of LCBs increases with increasing molecular weight, but the size of LCBs relative to the overall macromolecular size decreases with increasing molecular weight. The LCB sizes as a function of molecular weight determined for the fractions of one parent HPLDPE are in good agreement with those previously reported for HPLDPE whole polymers.