Victrex Polymer Solutions, A Division Of Victrex

Adding fillers to unfilled polymer enhances mechanicalperformance such as strength and stiffness andtherefore creep performance, with the increasedependent upon the type of filler and filler content.The high strength and stiffness characteristics ofPEEK and HT compounds under conditions of creepare shown in Figure 8 at 23 C and a constant loadof 90MPa.Figure 9: Tensile fatigue of a range of Victrex materialsat 5Hz at 23 C and 120 CPEEK 90HMF40, which has the highest strengthand stiffness properties of all Victrex materials,demonstrates outstanding creep resistance.PEEK 450CA30 and PEEK 450GL30 are showingsomewhat higher measurable time dependent creepat 90MPa compared to PEEK 90HMF40. HT compoundsshowed slightly improved creep performance opposedto PEEK based equivalents.Figure 8: Tensile creep of PEEK and HT compounds at 23 Cand constant stress of 90MPaIMPACT PROPERTIES300Tensile Strength [MPa]Impact testing is used to investigate the behaviourof materials under specific impact conditions andfor250estimating their toughness within the limitationsinherent to the test conditions. There is a vast varietyof test methods, low energy studies performed using200pendulum geometry and high energy studies wherefailures are evaluated using falling weight apparatus.Pendulumgeometry may use a cantilever support150as in Izod testing (ISO 180) or a 3-point-bendingconfiguration as in Charpy testing (ISO 179); with both100using notched or un-notched impact bars.Figures 10 and 11 show Izod and Charpy impact50strength of edgewise loaded samples for a range ofVictrex materials, notched and un-notched. UnfilledVictrexmaterials are extremely tough and do not break0510 710 2 configuration,10 810 110 310 610 4 Izod10or Charpy.in un-notchedAddingCycles to Failurefillers to PEEK enhances thenotched toughness.FATIGUE PROPERTIESFatigue may be defined as the reduction in mechanical1.4propertiesduring continued cyclic loading. Tensilefatigue was evaluated using ISO tensile bars stressedat1.25Hz with a sine wave between 10 and 100% ofpredefinedloads.1.0Tensile Strain [%]PEEK 90HMF40 [23 C]PEEK 90HMF40 [120 C]PEEK 450CA30 [23 C]PEEK 450CA30 [120 C]Figure9 shows the excellent fatigue performance0.8at 23 C and 120 C for a range of Victrex materials.0.6 450G shows very little decay in a tensile fatiguePEEKsituation at 23 C. Adding fillers to unfilled PEEK0.4enhances fatigue stress levels significantly.0.240.0-31010-210-110010Time [h]PEEK 450GL301102103PEEK 450GL30 [23 C]PEEK 450GL30 [120 C]PEEK 450G [23 C]

12Figure11:notchedCharpy Impact strength of various Victrexun-notched10materialsat 23 Un-notched Impact Strength [kJ/m2 ]Notched Impact Strength [kJ/m2 ]Figure 10: Izod Impact strength of various Victrexmaterials at 23 CCAVICTREX PEEK polymer specified for aircraft landing gear hubcapswithstanding impacts of flying debris and has excellent environmentalresistance in harsh conditions.THERMAL PROPERTIES4544022000Figure 12: Notched Charpy impact strength versus000030303022450GL3L3L3 VictrexF4G of GvarioustemperatureG 5KEE90TH22ST45Figure 13: The glass transition (Tg) and crystalline meltingtemperatures (Tm) for Victrex polymers determined by DSC(ISO 11357)T [ C ]12012Impactpropertiesnotched are temperature dependent asun-notched10shownin Figure 12 for a range of Victrex materials.100An8increase in toughness is measured as temperature80increasesfrom-55 Cto 120 C.606Un-notched Impact Strength [kJ/m2 ]Notched Impact Strength [kJ/m2 ]Victrex polymers have glass transition (Tg) andcrystalline melting temperatures (Tm) in the rangeshown in Figure 13. Due to the semi-crystalline natureof these polymers a high degree of mechanicalproperties is retained close to their 0PEEKJ/m2 ]17012HTST400 5

HEAT DEFLECTION TEMPERATUREHEAT AGEINGThe short term thermal performance of polymersmay be characterised by determining the HeatDeflection Temperature (HDT, ISO 75) at which adefined deformation is observed in a sample underconstant applied stress (1.8 MPa) at constant heatingrate. Victrex materials have excellent stiffness at hightemperatures and correspondingly have high HDTvalues when compared with other high performancepolymers.The excellent retention of mechanical properties atvarious ageing temperatures in air for unfilled PEEKwas determined as a measure of thermal ageingresistance. Results are shown in Figures 16 and 17. Theinitial increase in tensile strength observed in Figure 16is a result of increased crystallinity due to annealing.The subsequent decrease in strength with time is due tothermal degradation.Figure 14: Heat deflection temperature (at 1.8 MPa) forVictrex materials and other high performance polymersFigure 16: Retained tensile strength of unfilled PEEK versusconditioning time at high temperaturesRELATIVE THERMAL INDEX4000VICTREXCA30VICTREXGL30PAI 30% GLPPS 40% GLPPA 33% GLPES 30% GL140 17: Retained flexural strength following highFiguretemperature ageing for unfilled PEEK and HTRetention of Tensile Strength [%]HDT [ C ]Polymers are subject to thermal degradation at elevated350temperatures.These effects may be evaluated by300measuringthe Relative Thermal Index (RTI) as defined byUnderwritersLaboratories (UL746B). This test determines250the temperature at which 50% of a particular material200property is retained compared to a control material150whose RTI is already known (RTI typically corresponds to100extrapolatedtimes between 60,000 and 100,000 hours).The50UL RTI rating for Victrex materials compared to otherhigh performance polymers are shown in Figure 15.PEEKST IndexHT(RTI) – mechanicalFigure 15: Relative Thermalwithoutimpact – for a range of high performance materials1205000 h, 103%10080604020005001000150 C260 C160ural Strength [MPa ]140615002000Ageing Time [h]1201008060300 C320 C2500

COEFFICIENT OF LINEAR THERMALEXPANSIONThe Coefficient of Linear Thermal Expansion (CLTE)was measured according to ISO 11359. Materialswere studied in three axes to fully characterise theanisotropic effects of filled grades. Figure 18 showsthe variation in CLTE for standard PEEK grades in theflow direction and as an average of all three directions.Unfilled grades such as PEEK 450G are nearly isotropicand have little difference in expansion in differentdirections. However, glass fibre and carbon fibre-filledgrades are anisotropic and as such have low expansionin the flow direction but significantly higher expansiontransverse to flow. Also, there is a significant increasein CLTE as temperature is increased above Tg, with thedifference lower for compounds, particularly in theflow direction.The CLTE of a range of Victrex materials below Tg inthe flow direction are compared to various metals inFigure 19.Figure 19: Coefficient of linear thermal expansion(CLTE) for various Victrex materials versus metals (flowdirection, below Tg)Figure 18: Coefficient of linear thermal expansion (CLTE)for various Victrex materials below and above TgTHERMAL STABILITYCLTE [ppm/ C]50Thermogravimetry(TGA) illustrates the thermal45stabilityof PEEK in air. Degradation only starts above550 C40 with insignificant levels of outgassing at lowertemperaturesas can be seen in the comparative plot35of PEEK 450G and other high performance polymers in30Figure 20.25201510Figure 20: Thermogravimetry (TGA) analysis of PEEK and5other high performance polymers01600G140EKPECLTE [ppm/ C 0Below TgAbove TgFlow Direction OnlyPEEK 450GBelow TgAbove TgAverage of three directionsPEEK 450GL30PEEK 450CA30VICTREX PEEK polymer was selected in a cooling jacket application due tothe material’s dimensional stability, low radio frequency (RF) losses, and itsability to be precisely machined resulting in a new 1-part design.7

RHEOLOGYLike most thermoplastic materials the melt viscosity ofVictrex materials is temperature dependent and showsshear thinning. A comparative plot of melt viscosityat a shear rate of 1000/s for a range of highperformance polymers is shown in Figure 21. AlthoughPEEK has one of the highest processing temperatures,the melt viscosity of PEEK 450G is in the range ofpolycarbonate melts.Melt viscosity depends on base resin, filler type andfiller level. Materials based on PEEK 450 have higherviscosity than those based on PEEK 150 and PEEK 90.Blending Victrex polymers with fillers such as glass orcarbon fibre leads to higher viscosities as can be seenfrom Figure 22. Based on the high flow grade PEEK90G compounds with up to 60 weight-% filler contentare possible having a lower viscosity than 30% filledcompounds of standard viscosity PEEK 450G. The weargrades with 30 weight-% fillers have viscosities similarto other 30% filled products shown in Figure 22.Rheology of Victrex polymers is suitable for standard injection moulding aswell as for critical melt processing technologies such as extrusion ofAPTIV films.Figure 21: Melt viscosity at a shear rate of 1000/s at typicalprocessing temperatures for a range of thermoplasticsVICTREX PEEK polymer replaced steel in high-speed rotors and intricatebearing shells for dispersion instruments used in the medical industry.400Melt Viscosity [Pa.s ]350Figure22: Melt viscosity (1000/s; 400 C) of various Victrex300materials(ST at 420 C)250200150100500PA66(280 C)8700PA6T(320 C)PC(340 C)PES(390 C)PEEK 90G(400 C)PEEK 450G(400 C)

FLAMMABILITY ANDCOMBUSTION PROPERTIESto escape from the fire. Corrosive fire gases such ashydrogen fluoride (HF) and hydrogen chloride (HCl) willpermanently damage sensitive electronic equipment.Flammability can be defined as the ability of a materialto support combustion, a flammable material beingone which is easily ignited and burns rapidly.The combustion products of Victrex materials arepredominantly carbon dioxide (CO2) and carbonmonoxide (CO). The amount of CO is less than 5%of the limits specified in aviation toxicity standards(example Boeing BSS 7239, Airbus ATS-1000).Victrex mat

Tribology 13 Friction and Wear 13 Block on Ring 13 Thrust Washer 14 Limiting Pressure and Velocity 15 Environmental Resistance 16 Hydrolysis Resistance 16 Gas and Liquid Permeation 16 Chemical Resistance 17 Radiation Resistance 18 Outgassing Characteristics 18 Approvals and Specifications 19 Materials of Choice 20 Why Victrex PAEKs?