Vikram Sarabhai Space Centre has developed different types of resins catering to specific applications in Launch Vehicles and Satellites. These materials may also find various industrial applications such as bonding, sealing, coating, potting, laminating, molding, etc.

PF-108 is a special grade liquid phenolic matrix resin which is used as a precursor for production of silica phenolic throat inserts for the liquid engines of ISRO launch vehicles.

Operational steps for synthesising PF 108

1. Melting of Phenol.

2. Charging of formalin and molten phenol into the reactor in the desired mole ratio.

3. Addition of catalyst.

4. Condensation polymerization of phenol and formalin.

5. Neutralization of reaction mixture with acid.

6. Settling of reaction mixture

7. Removal of water of reaction and salt.

8. Vacuum drying of resin to remove the final traces of water and other volatiles.

9. Major equipments needed are phenol melting vessel and reaction vessel.

 1. Melting vessel for phenol melting

 2. Jacketed SS reactor fitted with cooling coils, stirrer, motor, condenser and receiver for polymerisation and drying. The reactor is suitably linked with the utility system during operation. It is also equipped with load cell, vacuum systems, temp controllers, cooling systems pressure/vacuum gauges etc.

 3. Decanter vessel for removal of water.

 4. Water jet ejector for vacuum.


PF 108 Product Specifications 
Appearance Yellowish brown to dark brown liquid
Viscosity 400 - 600 cps
Specific gravity 30°C 1.18 – 1.20
Refractive Index at 30°C 1.570 – 1.575
Total solid 72 – 75%
Free phenol (%) 18 – 22%
Free formalin (%) 0.5% (max.)
Ash Contact) 0.5% (max.)
Point of trouble 13 – 15.5 ml of water/10 ml solution
pH (5% solution) 7.3 – 7.8
Sodium Content 0.4% (max.)
Water Content 14% (max.)

Storage conditions 
Temperature <15°C
Shelf Life 3 months (in above condition)




ISRO is willing to offer the knowhow of this technology to suitable entrepreneurs / industries in India. Capable manufacturing industries interested in acquiring this knowhow may write with details of their present activities, requirements and plans for implementation, infrastructure and technical expertise available with them, their own market assessment, if any, and plans for diversification to the address given below:


Technology Transfer & Industrial Coordination Division (TT&IC)

Vikram Sarabhai Space Centre, ISRO PO

Thiruvananthapuram-695 022

E mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Ph: 0471-2564081

Fax: 0471-2564134

Ph: 0471-2564081/2565133/2565695

Fax: 0471-2564134 

Download Pdf File