Working of Organic Peroxides

Mechanism of action

Unsaturated polyester resins (or UP resin) refer to a large variety of products all containing reactive double bonds in the polymeric chain. The presence of double bonds provide the product with the ability to crosslink in the presence of a monomer, also acting as a diluent, via a free-radical mechanism.

The reactivity, the viscosity and the final properties of UP resins can be adjusted by:

  • chemical composition (aliphatic, aromatic, number of double bonds)
  • resin molecular weight
  • Nature and concentration of the crosslinking monomer (containing at least one double bond)
Example of chemical structure
Example of chemical structure

Mechanism of action

Unsaturated polyester resins (or UP resin) refer to a large variety of products all containing reactive double bonds in the polymeric chain. The presence of double bonds provide the product with the ability to crosslink in the presence of a monomer, also acting as a diluent, via a free-radical mechanism.

The reactivity, the viscosity and the final properties of UP resins can be adjusted by:

  • chemical composition (aliphatic, aromatic, number of double bonds)
  • resin molecular weight
  • Nature and concentration of the crosslinking monomer (containing at least one double bond)

The crosslinking monomer

In most cases the crosslinking monomer is Styrene introduced at concentrations between 25 and 45 wt%, but other monomers can also be used.

Curing catalyst

To initiate the curing reaction a source of radicals is needed. In most of the cases organic peroxides are used.

  • The first step is the decomposition of the peroxide.
  • The second step is chain propagation reaction via styryl radical formation capable to react with a double bond

For cold curing, initiators such as amines or metallic salts are also introduced.

Inhibitors

In order to prevent premature curing and to extend pot-life, inhibitors are also introduced into the system. Inhibitors are free radical scavengers like Hydroquinone derivatives, terbutylcatechol, cresol derivatives

Quick Links

About

News

Enquire

Privacy Policy

 

Awards

President's Gold Medal
Udyog Patra
Udyog Rattan

Address

M/s. Plasti Pigments Pvt. Ltd.
C-8/5, Pavne Village, TTC Industrial Area, Off Thane Belapur Road, Navi Mumbai - 400 703, Maharashtra, INDIA.

CIN No.

U14558MH1970PTC014558