Frequently Asked Questions
Common questions on specialty engineering plastics supplied by Lingli Trading. For specific quote / TDS request, contact us directly.
What is PEEK and what is it used for?
PEEK (Polyetheretherketone, 聚醚醚酮) is a high-performance semi-crystalline thermoplastic with continuous service temperature 260°C, excellent mechanical properties, hydrolysis resistance, inherent flame retardance (UL94 V-0), and USP Class VI biocompatibility. Used in aerospace (aircraft brackets, rocket engine components), medical devices (spinal fusion cages, surgical instruments), semiconductor (wafer chucks, CMP rings), EV battery (cell frames), and industrial (pump impellers, valve seats).
PEEK vs PEKK — what is the difference?
PEEK (Polyetheretherketone) and PEKK (Polyetherketoneketone) are both polyaryletherketone (PAEK) family polymers. PEKK has higher glass transition temperature (Tg ~162°C vs 143°C for PEEK), higher continuous service temp, and slower crystallization. PEKK is preferred for aerospace structural parts and 3D printing (higher layer adhesion). Both are supplied by Lingli Trading from China tier-1 producers.
Is PEEK FDA / USP Class VI approved for medical implants?
Yes. Medical grade PEEK (Victrex PEEK 450G or Evonik Vestakeep i4 G) is USP Class VI and ISO 10993 compliant, used in spinal fusion cages (FDA cleared), trauma plates, dental implants, and surgical instrument handles. Lingli Trading supplies medical grade PEEK with full traceability documentation (TDS / MSDS / DMF reference).
What is PVDF used for in lithium batteries?
PVDF (Polyvinylidene Fluoride) is the dominant binder technology for lithium-ion battery cathodes (and increasingly anodes). PVDF binder provides: (1) strong adhesion to active material particles and current collector, (2) electrochemical stability up to 4.5V vs Li/Li+, (3) flexibility for electrode coating. PVDF also used as separator coating (ceramic-PVDF composite) for improved thermal stability. HSV900 grade from Arkema / Kynar is industry standard.
Why is LCP used for 5G connectors?
LCP (Liquid Crystal Polymer) has extremely low dielectric loss tangent (Dk ≈ 2.9, Df < 0.005 at GHz frequencies) and near-zero moisture absorption, making it ideal for high-frequency RF connectors, high-speed I/O connectors, and 5G mmWave antenna components. Compared to PA9T and PPA, LCP supports higher frequencies (>10 GHz) and thinner wall sections for SMT connectors. Supplied by Ticona / Celanese / Sumitomo.
What is the temperature resistance of PPSU?
PPSU (Polyphenylsulfone) has heat deflection temperature (HDT) of 207°C at 1.8 MPa, glass transition temperature (Tg) 220°C, and continuous service temperature 180°C. It withstands >1000 cycles of steam sterilization (134°C autoclave) without significant property loss, making it the preferred material for medical device housings, sterilizable trays, and hot-water plumbing (Bluestone / Radel from Solvay).
How is PEEK processed (injection molding / 3D printing)?
PEEK is processed by: (1) injection molding at 360-400°C melt temp, 180-220°C mold temp, requiring high-temperature steel tooling; (2) extrusion at similar temps for rods / sheets / filaments; (3) compression molding for large shapes; (4) 3D printing (FDM) at 380-420°C nozzle, 120-150°C bed, requiring heated chamber. PEEK must be dried at 150°C for 3+ hours before processing to prevent hydrolysis.
What is PA46 and how does it compare to PA66?
PA46 (Polyamide 46) has higher melting point (295°C vs 265°C for PA66), higher heat deflection temperature (290°C vs 75°C), and better retention of mechanical properties at elevated temperatures. PA46 is preferred for SMT connectors, automotive under-hood parts, and high-temperature gears. Supplied by DSM (now Envalior) as Stanyl.
Why use PPA instead of metal in automotive connectors?
PPA (Polyphthalamide, semi-aromatic polyamide) replaces metal in automotive connectors because: (1) weight reduction 30-50%; (2) corrosion resistance; (3) integration of multiple functions into one molded part; (4) IR-reflow solderable (260-280°C). Glass-filled PPA (PPA-GF30 / GF50) is common. Supplied by Solvay (Amodel), DuPont (Zytel HTN), EMS-Grivory (Grivory HT).
What is the difference between PTFE and PFA?
PTFE (Polytetrafluoroethylene, Teflon) has the broadest chemical resistance and highest continuous service temperature (260°C), but is not melt-processable (must be sintered or ram-extruded). PFA (Perfluoroalkoxy) is a melt-processable copolymer of PTFE, allowing conventional processing (injection, blow, transfer) at slightly higher cost. PFA is preferred for lined pipe / valve / pump where complex shapes are needed. Both supplied by Lingli Trading from China tier-1.
Is PEEK recyclable?
PEEK is technically recyclable but challenging. Production scrap (sprues, runners, off-spec parts) can be reground and re-compounded with 10-30% virgin material. End-of-life PEEK parts can be chemically recycled (depolymerization) back to monomer. However, due to high cost and long service life (often 10+ years), most PEEK parts are not actively recycled. Lingli Trading offers reground PEEK at lower cost for non-critical applications.
What is the difference between PEEK and PEI (Ultem)?
PEEK is semi-crystalline thermoplastic with superior chemical resistance and fatigue performance; PEI (Polyetherimide, Ultem) is amorphous with better dimensional stability and transparency. PEEK for high-stress structural parts (260°C continuous); PEI for high-temperature housings, sterilizable medical devices, and electrical insulators (180°C continuous). PEEK is more expensive than PEI. Both supplied by Lingli Trading.
More questions? 24h response.
Send grade + quantity + application + destination. Free TDS / MSDS / RoHS / REACH.
Request Quote