The Molecular Structure of Polyethylene. III. Determination of Long Chain Branching¹

Crystallization of polyacrylonitrile: Growth mechanisms for various growth features

“…In the present study a fractionated sample having Mw = 1.2 × 105 was utilized for growing crystals. Cellulose triacetate (CTA) having molecular weight ~fn = 3.5 × 105 as determined from viscosity measurements in chloroform at 25 °C using the Harvard and Parikh relationship (10) while polyethylene (PE) having molecular weight Mn= 9.9 × 104 as determined from viscosity measurement in xylene at 90 ° using the Billmeyer relationship (11) are utilized for growing crystals. PE sample was kindly supplied by Chemische Werke Hills AG., Marl, Germany while CTA was prepared by acetylation of cellulose by acetic acid and acetic anhydride using perchloric acid as a catalyst.…”

Analytical Rheology of Polymer Melts: State of the Art

“…The "g-ratio" in g-ratio analysis is the ratio of the size of the branched and LPs of identical molecular weight. Theoretical estimates of g for different polymer architectures are available via Zimm-Stockmayer equations [67,68]. For example, the g-ratio of a star molecule, g star = (3 f − 2)/ f 2 , where f is the number of branches.…”

Light scattering studies of linear polyethylene

“…Polyethylene solutions are usually contaminated with insoluble particles. Billmeyer (2) mentioned in his work on high-pressure polyethylene that the solution usually clogged the ultrafine filter. Moore (3), Duch and Kuchler (6), and Kobayashi (10) et al encountered the same difficulty.…”

“…Light scattering techniques are now widely used in the determination of weight-average molecular weights of high polymers (1) and a number of applications to polyethylene of various types have been reported (2)(3)(4)(5)(6)(7)(8)(9)(10). One notes that the precision for these applications usually falls short of that generally obtainable from the technique.…”