Gel Permeation Chromatography (GPC)
Gel Permeation Chromatography (GPC) for measurement of polymer molecular weight, size and structure. Gel Permeation Chromatography (GPC) is an analytical technique that separates dissolved macromolecules by size based on their…
Fractionation of Polymers
Introduction In the working group of Professor Wolf two different kinds of polymer fractionation techniques were developed. They allow the production of large amounts of material with narrow molecular weight…
MOLECULAR WEIGHT AND MOLECULAR WEIGHT DISTRIBUTION
The polymerization process, whether proceeding by chain growth or by step-growth, is ruled by random events. The result is a mixture of polymers that vary in chain length. A polymeric material, therefore, cannot…
Molecular Weight Definition
Molecular weight is a measure of the sum of the atomic weight values of the atoms in a molecule. Molecular weight is used in chemistry to determine stoichiometry in chemical reactions and equations. Molecular weight is commonly…
Polymer Solutions
The importance assigned to polymer solutions, a topic whose discussion has evolved from a mere informative mention in textbooks to whole books exclusively devoted to that subject, has become increasingly…
SOLUTION POLYMERIZATION
In solution polymerization, the monomer, initiator, and the resulting polymer are all soluble in the solvent or solvent blend. In the case of free radical polymerization, the rate of the…
What is Rotational Moulding?
Rotational moulding is a unique plastic moulding process used primarily to create seamless, stress-free, hollow one-piece items. Also called rotomoulding, it is a high temperature, low pressure manufacturing method that combines heat…
CYCLIZATION VERSUS LINEAR POLYMERIZATION
The first theories of step-growth polymerization (SGP) were developed by Carothers, Arvin, Natta, and Dorough in the 1930th.1-5 Carothers and coworkers realized early on that in any step-growth polymerization, the formation…
MOLECULAR WEIGHT DISTRIBUTION IN LINEAR STEP-GROWTH POLYMERS
The molecular weight distribution of a linear condensation or addition polymer can be easily calculated if we assume that each functional group has an equal chance of reacting with other…
Condensation Reactions
In a condensation reaction, two molecules or parts thereof combine, releasing a small molecule. When this small molecule is water, it is known as a dehydration reaction. Other possible lost…
