Molecular Weight Distribution of Synthetic High Polymers

Gel Permeation Chromatography . I . A New Method for Molecular Weight Distribution of High Polymers

Polystyrene gels crosslinked in the presence of dilucnts have been iliatie in tinc-iiii.sli bead forni suitable for packing into chromatographic rolurnns. A series of narrow molecular weight range pol) mer fractions w&s eluted through such columns with aromatic and chlorinated solvents. EfHuent concentrations were detected and recorded by a continuous differential refractoineter. The fractions ...

Molecular Dynamics Simulation of Synthetic Polymers

Synthesis of high molecular weight polyethylene using FI catalyst

A FI Zr-based catalyst of bis[N-(3,5-dicumylsalicylidene)-2′,6′­diisopropylanilinato]zirconium(IV) dichloride was prepared and used for polymerization of ethylene. The effects of reaction conditions on the polymerization were examined in detail. The increase in ethylene pressure and rise in polymerization temperature up to 35 oC were favorable for catalyst/MAO to raise the catalytic activity as...

Molecular Weight Profiles of Proanthocy Anidin Polymers

The MW profiles of proanthocyanidin polymers (condensed tannins) from 32 samples representing a wide range of plant tissues of many different species have been obtained by gel permeation chromatography of the peracetate derivatives. The tannins vary widely in MW, with Al. values for the peracetates in the range 1600-5500. The MW profiles vary greatly from those with narrow, rather smooth distri...

Analysis of high-molecular-weight fructan polymers in crude plant extracts by high-resolution LC-MS

The main water-soluble carbohydrates in temperate forage grasses are polymeric fructans. Fructans consist of fructose chains of various chain lengths attached to sucrose as a core molecule. In grasses, fructans are a complex mixture of a large number of isomeric oligomers with a degree of polymerisation ranging from 3 to >100. Accurate monitoring and unambiguous peak identification requires chr...