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balance of tensile properties, shear strength, stiffness, and toughness and have a
better resistance to hot water, alkalis and better long term temperature properties.
Strength: very low COF against metals, excellent abrasion resistance, retention of
initial mechanical properties in almost all environment, good dielectric strength,
good dissipation factor, low dielectric constant over a range of frequencies, high
volume resistivity, and excellent arc resistance, excellent machinability, be painted,
hot stamping, metalizing, electroplating and welded with various methods, joining
by snap fit joints, threading and riveting.
Limitations: Opaque, High shrinkage, release formaldehyde (highly odorous,
good resistance to strong alkalis (copolymers) but less resistance to strong acids,
Low resistance to UV and gamma radiation, Flammable, bonding does not lead to
strong interfaces due to the good chemical resistance.
Applications: Gears, pumps, irrigation equipment, valves, pipe couplings,
conveyor links, medical insulin syringe, powder inhaler, Fuel caps, fuel pumps and
fuel lines in cars, windshield wiper components, heating and air conditioning control
systems, handles, loudspeaker grilles, seat belt components and zippers, springs
and bearings in domestic appliances, printers and hand tools, toys, shower heads,
clock and watch components, tea/coffee/espresso machines, food processor
blades, battery holder, bushings, cams, housings.
53) Polyphenylene Sulphide (PPS) :
A crystalline polymer having a symmetrical, rigid backbone chain consisting of
alternating sulfur atoms and phenylene rings in a para substitution pattern.
A variety of grades suitable for slurry coating, fluidized-bed coating, electrostatic
spraying, as well as injection and compression moulding are offered. Because of its
low viscosity, PPS can be moulded with high loading of fillers and reinforcements. In
practice only reinforced grades (with glass, carbon or aramide fibers) are available
which also covers for its inherent brittleness. PPS is also reinforced with mineral
powders; sometimes blended with LCP (Liquid Crystal Polymer).
Density 1.34 g/ cm 3
Glass transition temperature 88 - 93 °C
Max continuous service temperature 200 - 220 °C
Melting point 285 °C
Processing temperature: 300 to 350°C
Injection Moulding: A mould temperature of 140 °C is recommended to obtain
good crystallisation and minimise warping. For higher productivity, a mould
temperature of 50°C followed by a post crystallisation at 200 °C is possible, but not
recommended for applications requiring high dimensional stability.
PPS is a tough, opaque material having excellent stiffness, good mechanical and
electrical insulation properties, high temperature resistance, dimensional stability,
chemical and moisture resistance, flame resistance, exceptional high modulus and
creep resistance, good tensile strength, low coefficient of friction, good flowability.
PPS exhibit extreme inertness toward organic solvents and corrosive chemicals
even at elevated temperatures has not been found to dissolve in any solvent at
temperatures below about 200°C. PPS tends to char during combustion, making
the material inherently flame retardant. Find application replacing metals and some

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