PEEK Material Properties PDF

Polyether –PEEK (Victrex) Dr. Dinesh Kumar Kotnees Department of Metallurgical and Materials Engineering Indian Institute of Technology Patna Presentation Outline:  Introduction: * What is PEEK?  Formation: * PEEK  Properties and applications. *C...

Polyether –PEEK (Victrex) Dr. Dinesh Kumar Kotnees Department of Metallurgical and Materials Engineering Indian Institute of Technology Patna Presentation Outline:  Introduction: * What is PEEK?  Formation: * PEEK  Properties and applications. *Chemical, Thermal  How are they processed? * Processing of PEEK  Introduction –Polyetheretherketone -PEEK Aryl  Chemical Constitution :Polyether ether ketone (PEEK) is a colourless organic thermoplastic polymer in the polyaryletherketone (PAEK) family, used in engineering applications C=O  Polyetheretherketone (PEEK) withstands high temperatures and is resistant to chemicals and radiation.  Ether groups in the back bone will increase the Chemical Structure of PEEK flexibility of the main chain, which in turn will reduce the Tg and Tm (irrespective of the number of benzene rings in the main chain)  As evident from the chemical structure, PEEK contains relatively stiff aromatic polymer backbone and remains a reason for high thermal transitions.  As a result, these polymers have a ‘continuous use temperature’ of around 240°C, even in hot water or steam.  The rigid and stiff chemical structure affects the crystallisability of PEEK and allows up to 48% maximum achievable crystallinity.  Formation of PEEK  PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts.  Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of hydroquinone, which is generated in situ by deprotonation with sodium carbonate. The reaction is conducted around 300 °C in polar aprotic solvents - such as diphenyl sulphone. sodium carbonate Hydroquinone Disodium salt of hydroquinone 4,4'-difluorobenzophenone  Thermal properties of PEEK  The high thermal stability is provided by the diphenylene ketone groups which impart high strength and high resistance to oxidation degradation, but make the polymer rigid.  Flexibility in the polymer backbone is provided by ether linkages which also add to the thermal stability.  PEEK has a glass transition temperature of around 143 °C (289 °F) and melts around 343 °C (662 °F)  Chemical properties of PEEK  It is attacked by halogens and strong acids as well as some halogenated compounds and aliphatic hydrocarbons at high temperatures.  It dissolves completely in concentrated sulfuric acid at room temperature.  Comparison to other polymers  In comparison to fluoropolymers, PEEK show superior tensile strength, HDT, operating temperature, bonding, processing and toxic gas emission; but they are inferior in terms of chemical resistance, cost, toughness and UV weathering  As compared to PPS, PEEK has markedly superior thermal resistance, toughness and flashing  PEEK has much higher temperature performance, wear resistance, chemicals resistance and fatigue performance as compared to PES  Processing of PEEK  The presence of ether linkage gives the melt processability in conventional techniques such as injection moulding, compression moulding and extrusion.  Applications of PEEK  Good materials for an aggressive environment. PEEK is being used in nuclear environments, oil and geothermal wells, chemical industries, and high- pressure valves.  PEEK is ideal for metal replacement applications mainly because of its outstanding corrosion resistance, strength, durability, wear resistance and high- temperature stability.  FDA approved materials: FDA approval of PEEK materials finds its application in food processing industry mainly as a bearing and seals for food processing equipment.  Key Properties of Polyetheretherketone (PEEK) 1.PEEK has V0 flammability rating down to 1.45 mm and an LOI of 35%. Its smoke and toxic gas generation are extremely low 1.PEEK exhibits exceptional tensile properties. When 2.Crystallinity imparts excellent resistance to wide range if liquids and reinforced with carbon fibers, tensile strength of 29000psi superb fatigue performance can be achieved with excellent properties retained at 299°C 3.PEEK is insoluble in all common solvents. It does not undergo 2.The polymer also exhibits excellent creep resistance. When hydrolysis and can be used for thousands of hours in steam or high- combined with flexural & tensile characteristics, it provides an pressure water without significant property degradation excellent balance of properties where the material is required to withstand high loadings for long periods at high 4.More properties of PEEK include: temperature without permanent deformations 1. Low friction 3.Its flexural modulus at very high temperatures can further 2. Good dimensional stability be improved with glass- or carbon-reinforcement. 3. Exception insulation properties (Reinforcement also increases creep and fatigue resistance, 4. Excellent sterilization resistance at high temperature thermal conductivity of the polymer as well as heat distortion 5. Biocompatible temperature) 6. Long life 7. Inherent purity 4.The polymer exhibits high volume resistivity and surface resistivity. It can maintain good insulating properties in a Limitation of PEEK broad temperature range and environmental changes 1.Expensive, applicable for highly demanding application 2.Processing at high temperatures 3.Attached by some acids, such as conc. Sulphuric, Nitric, Chromic… and is attacked by halogens and sodium 4.Low resistance to UV light