Polyphenylene sulfide (PPS) belongs to the small group of thermoplastics that hold their shape and their strength in continuous heat above 200 °C, resist fuels, coolants and cleaning solvents, and meet a flammability requirement without added flame retardants. It is not a general-purpose resin and it is not a cheap one, so it tends to be specified after a cheaper material has already failed.
What PPS is
PPS is a semi-crystalline engineering thermoplastic whose backbone alternates aromatic rings with sulfur atoms. That structure produces the three properties buyers usually come for:
- Heat. Melting point around 280–285 °C and continuous service in the 200–220 °C band, so parts survive reflow soldering, engine-bay heat and repeated sterilisation.
- Chemical resistance. Unaffected by fuels, oils, coolants, brake fluid, ketones and most organic solvents, and by aqueous acids and bases. Strong oxidising acids are the known exception.
- Dimensional stability. Water absorption below 0.05 %, so a part moulded to tolerance stays there in humid or immersed service instead of growing the way PA or POM does.
Two more points come up in almost every project. PPS is inherently UL94 V-0 without halogenated additives. And unfilled PPS is brittle — it is normally chosen for electrical insulation, thin-wall flow or purity, while structural parts are glass-fibre or mineral filled.
Typical properties
Indicative values for the two families we supply most, for material selection only. The controlling figures are the producer’s TDS and the certificate of analysis for the batch you receive.
| Property | Unfilled PPS | Glass-fibre reinforced | Note |
|---|---|---|---|
| Density | 1.34–1.36 g/cm³ | 1.55–1.70 g/cm³ | GF30 to GF40 |
| Melting point | 280–285 °C | 280–285 °C | Crystalline phase |
| Glass transition | 85–90 °C | 85–90 °C | |
| Continuous service temperature | 200–220 °C | 200–220 °C | Without load |
| HDT at 1.8 MPa | 105–115 °C | 255–265 °C | Annealed |
| Water absorption, 24 h | < 0.05 % | < 0.05 % | Near zero |
| Moulding shrinkage | 0.6–1.4 % | 0.2–0.5 % | Tool design input |
| Flammability | UL94 V-0 | UL94 V-0 | Inherent, no additive |
Grade families we supply
PPS is sold as a family of compounds rather than one resin, and the difference between two grades is usually the filler system or the flow, not the polymer. These are the families in our current stock:
| Family | What it is for | Grades in this range |
|---|---|---|
| Unfilled neat resin | Electrical insulation, high purity, thin-wall flow where glass would break down | R-4-001 |
| Food-contact | Parts that come into contact with food or beverage, subject to the producer’s declaration | R-4-001NA |
| High flow | Long flow paths, thin sections and tools that are hard to fill | R-4-011 |
| Impact-modified | Fasteners, clips and parts that see mechanical shock rather than steady load | R-4-200, R-10-006 |
| Glass-fibre reinforced | Structural parts, tight tolerances, stiffness and creep resistance at temperature | R-7-02, R-7-110, R-7-120NA, R-10-400A |
Available grades
All grades below are in the PPS category and can be quoted individually. Ask for the TDS of any one of them and we will send the producer datasheet together with a COA from the batch in stock.
| Grade | Family | Usually specified for | Datasheet |
|---|---|---|---|
| Syensqo R-4-001 | Unfilled neat resin | Insulation, high-purity parts, thin-wall flow | R-4-001 |
| Syensqo R-4-001NA | Food-contact | Food and beverage contact parts | R-4-001NA |
| Syensqo R-4-011 | High flow | Thin walls, long flow paths, complex cores | R-4-011 |
| Syensqo R-4-200 | Impact-modified | Clips, fasteners, shock-loaded parts | R-4-200 |
| Syensqo R-7-02 | Glass-fibre reinforced | Structural parts, housings, creep-resistant load paths | R-7-02 |
| Syensqo R-7-110 | Glass-fibre reinforced | Stiff parts with tight dimensional tolerance | R-7-110 |
| Syensqo R-7-120NA | Glass-fibre reinforced | Dimensionally critical mouldings | R-7-120NA |
| Syensqo R-10-006 | Impact-modified | Repeated-impact and fatigue-loaded parts | R-10-006 |
| Syensqo R-10-400A | Glass-fibre reinforced | High-stiffness structural parts in heat | R-10-400A |
| PPS pellets (general purpose) | Unfilled / base resin | Compounding, trials, applications without a named grade | PPS pellets |
How to choose between them
1. Start from the process, not the data sheet
If the wall is under about 1 mm, the flow length is long or the tool has thin cores, a high-flow grade fills first and a glass-filled grade may not fill at all. If the part must simply not distort, glass-filled wins and the extra cost is repaid by a stable process window.
2. Match the duty cycle
Steady heat with load calls for glass-fibre reinforcement, because the heat deflection temperature of unfilled PPS sits near 110 °C while a reinforced grade holds above 255 °C. Repeated impact and snap-fit assembly call for an impact-modified grade — standard PPS is brittle enough that a clip will crack in service even though its tensile data looks adequate.
3. Separate compliance from performance
PPS is available in food-contact, drinking-water and medical variants, but the grade name alone does not prove compliance. If the part is regulated, tell us the regulation and the market at the inquiry stage: we will request the producer’s declaration of conformity and the migration data together with the COA, and you can decide against the actual document rather than a marketing claim.
Documentation, packing and terms
| Minimum order | One 25 kg bag and up; a single pallet is the usual starting point. Mixed grades on one order are fine. |
| Documentation | COA for every batch, TDS on request, plus REACH / RoHS statements where the producer issues them. |
| Packing | 25 kg moisture-barrier bags on pallet; jumbo bags for compounders. |
| Lead time | Quoted per grade and quantity — stock lots move faster than indent material, and we tell you which one you are getting before you commit. |
| Terms | FOB Shanghai, CIF or DDP, with export documents issued from Shanghai. |
PPS questions we get asked
Is PPS the same as PPSU?
No. PPS is semi-crystalline, opaque, cheaper and chemically tougher. PPSU is amorphous, transparent, considerably more impact-resistant and can be repeatedly steam-sterilised. If the part has to survive autoclaving, PPSU is usually the right answer; if it has to survive fuel and 200 °C continuously at lower cost, it is PPS.
Why is unfilled PPS brittle?
The same rigid aromatic backbone that gives it heat resistance gives it low elongation. Unfilled PPS is strong in compression and stiffness but poor in impact. Where a part will be dropped, snapped or fastened under load, an impact-modified or glass-filled grade is the practical choice.
Can PPS be used in food contact?
Yes — there are food-contact grades, and R-4-001NA in our range is listed as one. Compliance depends on the declaration and migration testing issued for that grade against your market’s rules (EU 10/2011, FDA, or the local equivalent), so request the documents before validating a mould.
Do you supply PPS for compounding?
Yes. General-purpose PPS pellets are available for compounders and for trials where a named grade is not yet fixed. Tell us the target filler loading and we will quote a base resin that suits it.
Request a datasheet or a price
Send us the grade you are looking at, the process and the volume. If you are still choosing, describe the part — temperature, chemical exposure, wall thickness and impact — and we will come back with two or three candidate grades with their TDS so you can compare them on paper before you buy.