Application Note- G-PAEK - PEK (Polyether Ketone) an ideal Polymer for Nuclear Power sector. Gharda Chemicals a specialty chemical company, engaged in the business of manufacturing Agrochmicals, Specialty Pigments and Specialty Polyemers has now added a feather in its cap by successfully commercializing PEK (Polyether Ketone) under the brand name G-PAEK. PEK is n ultra performance engineering polymer with exceptionally high heat resistance, having maximum service temperature rating upto 280 deg C. The salient features of PEK polymer is as under.

Gamma ray Radiation resistance upto 1000Mrads. (Best in class) Excellent chemical resistance. (Only affected by few solvents and

acids.) Heat resistance upto 280 deg C. Retention of mechanical properties at elevated temperatures Strength to weight ratio similar to that of steel. High Surface hardness. Excellent hydrolytic stability. Thermoplastic with good processing ability for Injection moulding,

extrusion. Oustanding triboloical properties with excellent wear resistance.

All these properties (Table-1) make PEK an ideal polymer for engineering applications and an ideal substitute to metals, particularly in Nuclear Applications.

Table-1: Thermal, Rheological, Mechanical and Flammability properties of G-PAEK 1200G

PROPERTY TEST METHOD/CONDITIONS UNIT G-PAEK1200G General Properties Density 23C g/cc 1.30Water Absorption ASTMD 570-98 % 0.08Rockwell Hardness ASTMD785/M Scale 103Shore D Hardness ASTM D2240-05 86 Mold Shrinkage (400C nozzle, 210C M Along Flow % 1.0 Across Flow % 1.3Thermal Properties Glass Transition Temperature(Tg) ASTM D3418 C 152Melting Point (Tm) ASTM D3418 C 372Heat Deflection Temperature (HDT) ASTM D648 /1.8 MPa C 167Continuous Use Temperature UL 746B/ Expected C 280Mechanical Properties Tensile Strength ASTMD 638 MPa 110Tensile Modulus ASTMD 638 GPa 4.2Elongation at Break ASTMD 638 % 10-15Flexural Strength ASTMD790 MPa 185Flexural Modulus ASTMD790 GPa 4.1Izod Impact Strength(Notched) ASTMD256 J/m 60 Izod Impact Strength(Un-notched) ASTMD256 J/m No BreaRheological Properties Melt Viscosity at 400C ASTMD 3835/@1000 s-1 Pa.s 200Electrical Properties Dielectric Strength ASTMD 149/ 3.2mm thickness Kvmm-1 14 Surface Resistivity ASTMD 257 1016

Volume Resistivity ASTMD 257 cm-1 1016

Arc Resistance ASTMD 495/@ 500 Volts Sec 175CTI ASTMD 3638 V/50 drop 145Fire Properties Flammability UL 94/0.8 mm - V-0

G-PAEK 1200G (Unfilled natural PEK polymer) has been tested for 200 Mrad Gamma ray radiation exposure at BRIT (Board of Radiations and Isotopes Technology), Navi Mumbai. The exposed samples have been tested for Tensile Strength, Flexural strength & Elongation at Break properties with very little change. The tables shows that there is virtually no change in Tensile., Flexural strength & Impact Strength properties w.r.t Gamma ray Radiation exposure dosage, upto atleast 200 Mrads. (Table 2,3 & 4)

Table 2 Effect of Gamma ray on Tensile & Flexural Strength of G-PAEK 1200G Table 3: Effect of Gamma Ray on Impact Strength of G-PAEK 1200G.

Table-4 : Effect of Gamma Ray on Elongation at Break properties of G-PAEK 1200G These important properties makes PEK a unique & desirable polymer to be used in Nuclear Power Installations. Some of the proposed applications.

a. Seals, Bearings, Bushings b. Also as Wire and cable insulating materials. c. Also available for Surface coating application on Metals for chemical

and radiation protection. A comparative Property chart (Table 5) of Gamma Ray radiation resistance of PEEK/PEK with other polymeric materials is shown below. PEK has been reported to resist 5000 Mrad radiation exposure which is much higher then any of the available thermoplastic materials. (G-PAEK 1200G has been tested successfully at BRIT, Navi Mumbai for 200 Mrad exposure to Gamma Rays without any change in properties).

Table 5 : The bar chart shows the maximum withstanding exposure to Gamma rays for various polymers. G-PAEK (PEK) polymer is available as powders for coatings, pellet for Injection moulding and also as rods and plates for machining components.

TEST METHOD/CONDITIONSUNIT