PPS is specified for heat, chemicals and dimensional stability — at a cost. These questions cover the numbers behind that decision, and the processing constraints that come with a 300°C melt.
PPS (polyphenylene sulfide) is a semi-crystalline high-performance thermoplastic with a 280–290°C melting point and continuous service around 200–240°C. It is inherently UL94 V-0 without additives, resists acids, solvents and hydrolysis, and holds tolerances far better than nylon.
Unfilled PPS is 1.34–1.36 g/cm³; 40% glass fibre takes it to 1.6–1.7 g/cm³. Despite the higher density than PA66, PPS parts are often lighter overall because stiffness allows thinner walls.
PPS melts at 280–290°C — the highest of the three materials here — and needs barrel temperatures of 300–330°C with hot runners rated for it. Below 290°C the melt is too stiff to fill thin sections.
HDT is about 200°C unfilled and 260–275°C with glass fibre at 1.80 MPa; continuous service is quoted at 200–240°C with short excursions to 260°C. That puts PPS a full step above PA66 for engine-bay and soldering-adjacent parts.
Only 0.02–0.05% in 24 hours — effectively nothing compared with nylon. This is why PPS holds microns-level tolerances and why it is preferred for precision connectors and pump components. It still needs drying at 150–160°C for 3–4 hours, mainly to remove surface moisture.
0.2–0.8%, dropping to 0.2–0.4% with glass fibre. Shrinkage depends heavily on mould temperature and crystallisation, so tools are usually cut after a mould-flow study rather than by rule of thumb.
90–100 MPa unfilled, 180–200 MPa with 40% glass fibre. The weak point is toughness: notched impact is 5–10 kJ/m², so impact-modified or alloyed grades are used where parts see knocks or snap-fits.
Yes — unfilled PPS reaches UL94 V-0 on its own with an oxygen index above 44%, without halogenated or phosphorus additives. That makes it attractive for electrical parts where a clean material declaration matters.
Barrel 300–330°C, mould 130–150°C. Low mould temperature is the classic mistake: it drops crystallinity, and the part comes out brittle and dimensionally unstable. Hot-runner systems and heater bands must be rated for the temperature.
The melt is aggressive — use a high-nickel or bimetallic barrel and screw, and expect shorter component life than with PA. Purging compound and a proper shutdown sequence matter more than with commodity resins.
PPS sits above the PA family on both resin and processing cost: the monomer route, the 300°C+ processing window and the glass or mineral loading all push the number up. Unfilled extrusion grade is the cheapest entry point; 40% GF and alloyed grades are the top of the range. Specify temperature and chemical exposure first — over-specifying PPS where PA66 would do is the most common cost error.
Below 200°C, PA66 is usually the better buy: tougher, easier to mould, cheaper. Move to PPS when continuous temperature exceeds 200°C, when the part sees fuels, acids or solvents, when inherent V-0 is required, or when tolerances must hold in humid conditions.
Water-pump impellers and housings, connectors and coil formers, chemical pump and valve parts, 5G and telecom structures, and water fittings — anywhere heat, chemicals or moisture would defeat nylon.
Unfilled extrusion grade, 15/30/40% glass fibre reinforced, mineral-filled, impact-modified and alloyed (PPS/PA, PPS/PTFE for wear). Unfilled gives chemical resistance and purity; glass fibre adds stiffness and HDT; alloys trade some heat resistance for toughness.
Send the part, the service conditions and your monthly volume — we will propose an equivalent grade, a sample and a quote.