✦ LIBER ✦

Inter-molecular vibrations of crystalline polyethylene and long-chain paraffins

✍ Scribed by G.D. Dean; D.H. Martin

Publisher: Elsevier Science
Year: 1967
Tongue: English
Weight: 158 KB
Volume: 1
Category: Article
ISSN: 0009-2614
DOI: 10.1016/0009-2614(67)80054-x

No coin nor oath required. For personal study only.

✦ Synopsis

Within crystalline regions of polyethylene the molecular axes are parallel. The cross section perpendicular to the molecular axes shows an elementary cell containing two molecules with the relative orientations illustrated in fig. 1. The longer odd n-paraffins crystallise in layered orthorhombic structures in which the molecules in each layer have relative orientations similar to those in polyethylene.

Group theoretical considerations show that the two optical normal mode vibrations of the lattice illustrated in fig. 2 are infrared active as a result of the molecular distor-

📜 SIMILAR VOLUMES

Molecular-weight distribution and long-c

Molecular-weight distribution and long-chain branching of low-density polyethylene

✍ Joseph Miltz; Arie Ram 📂 Article 📅 1971 🏛 Elsevier Science 🌐 English ⚖ 461 KB

Gel permeation chromatography of polyeth

Gel permeation chromatography of polyethylene. II. Rapid evaluation of long-chain branching and molecular weight distribution

✍ L. Wild; R. Ranganath; A. Barlow 📂 Article 📅 1977 🏛 John Wiley and Sons 🌐 English ⚖ 712 KB

A comparison is made of two methods by which one may derive molecular weight distribution and degree of long-chain branching using only the measured solution viscosity of a branched polyethylene whole polymer and its GPC trace. These are (a) Drott and Mendelson method and (b) Ram and Miltz procedure

Correlations between the Shape of Viscos

Correlations between the Shape of Viscosity Functions and the Molecular Structure of Long-Chain Branched Polyethylenes

✍ Florian J. Stadler; Helmut Münstedt 📂 Article 📅 2009 🏛 John Wiley and Sons 🌐 English ⚖ 627 KB

## Abstract The viscosity functions of long‐chain branched metallocene‐catalyzed ethene homopolymers and copolymers (LCB‐mPE) were described by an extended Carreau‐Yasuda model. The two characteristic relaxation times, __λ__~1~ and __λ__~2~, and the slope of the viscosity function between these two

Effects of molecular weight distribution

Effects of molecular weight distribution and long-chain branching on the viscoelastic properties of high- and low-density polyethylene melts

✍ Chang Dae Han; Carlos A. Villamizar 📂 Article 📅 1978 🏛 John Wiley and Sons 🌐 English ⚖ 901 KB

Prediction of the Bivariate Molecular We

Prediction of the Bivariate Molecular Weight-Long Chain Branching Distribution in High-Pressure Low-Density Polyethylene Autoclaves

✍ Apostolos Krallis; Prokopis Pladis; Costas Kiparissides 📂 Article 📅 2007 🏛 John Wiley and Sons 🌐 English ⚖ 502 KB

## Abstract In the present study a population balance approach is described to follow the time evolution of bivariate molecular weight‐long chain branching (MW‐LCB) distributions in high pressure low density polyethylene autoclaves. The model formulation is based on a sectional grid method, the so‐

Sizes of long-chain branches in a high-p

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

✍ Takao Usami; Yukitaka Gotoh; Sigeru Takayama 📂 Article 📅 1991 🏛 John Wiley and Sons 🌐 English ⚖ 307 KB 👁 2 views

## 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 leng