In situ polymerization
Encyclopedia
In polymer chemistry, in situ means "in the polymerization mixture." There are numerous unstable oligomer
s (molecule
s) which must be synthesized in situ (i.e. in the reaction mixture but cannot be isolated on their own) for use in various processes.
Example of this method include urea-formaldehyde
(UF) and melamine formaldehyde (MF) encapsulation systems.In such type of in situ polymerization a chemical encapsulation technique is involved very similar to interfacial coating. The distinguishing characteristic of in situ polymerization is that no reactants are included in the core material. All polymerization occurs in the continuous phase, rather than on both sides of the interface between the continuous phase and the core material.
Oligomer
In chemistry, an oligomer is a molecule that consists of a few monomer units , in contrast to a polymer that, at least in principle, consists of an unlimited number of monomers. Dimers, trimers, and tetramers are oligomers. Many oils are oligomeric, such as liquid paraffin...
s (molecule
Molecule
A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...
s) which must be synthesized in situ (i.e. in the reaction mixture but cannot be isolated on their own) for use in various processes.
Example of this method include urea-formaldehyde
Urea-formaldehyde
Urea-formaldehyde, also known as urea-methanal, named so for its common synthesis pathway and overall structure, is a non-transparent thermosetting resin or plastic, made from urea and formaldehyde heated in the presence of a mild base such as ammonia or pyridine...
(UF) and melamine formaldehyde (MF) encapsulation systems.In such type of in situ polymerization a chemical encapsulation technique is involved very similar to interfacial coating. The distinguishing characteristic of in situ polymerization is that no reactants are included in the core material. All polymerization occurs in the continuous phase, rather than on both sides of the interface between the continuous phase and the core material.