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This work/thesis is dedicated to EU project 'SAFEPROTEX'; entitled 'High protective clothing for complex emergency applications'. The concept of the project lies in the development of protective uniforms, incorporating multiple protective properties and designated for rescue teams under complex risky conditions met in various types of particular and everyday emergency operations.
The key scope of the Work Programme(s) is to develop the uniforms using new/innovative materials and advance processing techniques in order to provide the best possible solutions to the 'risky operations' being stated in the frame of SAFEPROTEX. The project is highly multidisciplinary and requires developments in diverse areas such as polymers science, technology and processing, new additive masterbatches development and fiber spinning, nanotechnology, sol-gel technology, smart thermoregulating materials, microencapsulation, plasma technology, ergonomic garment design, etc.
This particular work is based on the production of filaments yarns made of PEEK and Feasibility report on it, under the project Work Package 2. The work dealt with the feasibility study aiming to investigate the possibility of spinning of PEEK into fibers and yarns with SMART and FUNTIONAL CHRACTERISITCS. It deals with the study to modify the process ability by BLENDING with other polymers and plasticisers. It includes the methodology to chemically generate in-situ BPK radicals and to chemically control the compatibility between PEEK and Benzophenone to get the required characteristics. The best findings compounds will be processed in a continuous pilot scale melt spinning line to produce large amounts of both single and multi filaments of the PEEK compound.
Also, the properties, characteristics and difficulties regarding the melt spinning, polymer theology, oxidative stability, measurements of DSC and TGA will be determined. Laboratory scale fabrics samples will be manufactured too, to examine/evaluate the fillers dispersion in the filaments by microscopic techniques (SEM, TEM, AFM). Various paper and patents and cited too to provide an overview on key aspects of the commercial technology, production, historical and up-to-dates information on manufacturers, diverse product forms and applications.
SAFEPROTEX is a collaborative project, based on 19 partners enlisted in project proposal. The consortium is coordinating by Dr. Silvia Pavlidou . The duration of the project is 42 months, from 2009-2013.
This particular work of the project is being performed by Danish A Chandna (HB), under the Supervision of Prof. Micheal Skirfvars (HB, TUT)
Part B: Bibliographic Analysis on PEEK Technology
PEEK, used to be known with many 'Advance' names and remarkable characteristics. Its temperature performance, biocompatibility, chemical inertness, polymer purity, irradiation uniqueness, LOI, oxidative stability, procesability makes a par true 'high performance engineering thermoplastic' polymer. That's why, it applications area is huge and diverse and founds applications in niche applications in almost every sector at, we humans are close to. Whether, aerospace, automobile, protection, industry, medical (implantable), sports, electronics.
PEEK (polyetheretherketone) is the foremost member of PAEK (Polyaryl  etherketone) family. Thus, PEEK can also be described as Polyaryletheretherketone. However, the other variants include PEK (polyaryletherketone), PEKK polyaryletherketoneketone, PEEKK and PEKEKK.
PEEK has the semi-crystalline aromatic structure with a polymer repeat unit of one ketone and two ether groups. Its structure is linear, compact, fully aromatic which is the core of the many its valuable characteristics (Mallakpour & Kowasari, 2004), (Dahl & Jansons, 1995), (Rao, 1995) The typical structure of PEEK is being illustrated in figure 1.
Figure â€Ž1.1 PEEK (Polyetheretherketone) monomer unit, showing two ether [-O-] groups linked with Aryl rings in a carbon chain with one ketone [-C=O-] group
The other variants of PAEK are generally quite similar despite having little nuances in terms of morphology as occurrence of polymorphism (Kemmish, 2010) in other nomenclatures and slight difference in thermal properties. Since, Tg increases with increasing ketone to ether ratio. Also, the presence of ketone increases chain polarity and rigidity. further details can be found in section
PEEK has a lamellar and spherulitic  structure. The crystalline unit cell itself has a chain axis repeat length of about 1 nm. The repeating unit runs from carbonyl and to ether since these groups are found to be crystallographically equivalent. The unit cell are the basic unit of the crystalline lamellae themselves radiate out from a centre of nucleation to form spherulites which are around 1 to 10µm in diameter. The simplest way to observe the spherulitic morphology PAEK is by hot-stage microscopy (Kemmish, 2010). Further, details have been presented in the literature (Blundell, Crick, Fife, Peacock, Keller, & Waddon, 1989); (Kemmish, 2010).
The regular techniques for measuring crystallinity are density, FTIR, DSC (Jonas, Legras, & Issi, 1991) and WAXS  . The crystallization of PEEK generally matches the classic behavior of other polymers. The effect of time is described by Avrami Kinetics (n~3) and secondary crystallization occurs after the spherulites impinged. This secondary crystallization is probably related to the existence of low-temperature melting peaks (LTMP). However, crystallization process in PEEK can be found in more (Kemmish, 2010) and as in (Medellin-Rodriguez & Philips, 1996); (Jenkins, Hay, & Terill, 2003)
The rate of crystallization vary with molecular weight, nucleation density and decreases with thermal and thermal oxidative degradation. It also effects if polymer melts at high enough temperature, as referred (Kemmish, 2010) in (Blundell & Osborne, 1985) (Day, Suprunchuk, Cooney, & Wiles, 1988); (Lee & Porter, 1988).
MFI  , capillary rheometry and Gel Permeation Chromatography (GPC), often used to identify the molecular weight. In past, the solubility of PEEK was a big hindrance. Later, when it has been found that PEEK is soluble in Phenol/tricholorobenzene and in chloropehnol/dichlorobenzene (Devaux, et al., 1985). GPC, comparatively become a more standard technique. Since, melt viscosity is related to molecular weight
Log10 (MW) = -15.06 + 3.21 log10Mw
Equation â€Ž2.1 Mark-Houwink Parameter
Where MW is the melt viscosity at 400 OC and a sheer rate of 1000 s-1 (Kemmish, 2010).
These solvents can be used at just 40 oC (Hay & Kemmish, 1989). Polydispersity is typically between ~2 and ~3 as would be expected for a transetherified (i.e., reversible reaction) condensation polymer.
Manufacturing and Polymerization
There are two major routes of manufacturing of PEEK and its variants
The principle of the process based on the nucleophilic  polyetherisation routes which involves the displacement of the activated halogen by phenoxide actions. For carbonyl monomers the halogen is usually fluoride but sulfone groups are more powerfully activating and chlorine is an adequate leaving group (Kemmish, 2010).
The route employs hydroquinone and 4,4_-dihalobenzophenone with a base as a catalyst, in solvents, such as N-methyl-2-pyrrolidone (NMP) or sulfolane. For example, PEEK is manufactured by the reaction of 4,4_-difluorodiphenyl ketone with the potassium salt of hydroquinone, as shown in Figure 3.1 (Fink, 2008).
The reaction temperatures are about 200-250 oC. The PEEK so produced, however, exhibits a low-molecular weight with an intrinsic viscosity (IV) smaller than 0.7 dlgâˆ’1 and comparatively low mechanical properties.
This route can be improved, by using diphenyl sulfone as a high-boiling solvent (Rose & Staniland, 1982.) Referred from (Fink, 2008). In this process, hydroquinone is transformed into its dipotassium salt by heating with an equivalent amount of potassium carbonate or potassium bicarbonate, with simultaneous removal of the water at 150-200 oC, followed by the addition of the second monomer, namely, 4,4_-difluorobenzophenone. The polymerization reaction is carried out at 320-350 oC to obtain a polymer of an IV in the range of 0.8 to 1.4 dlgâˆ’1 with a melting point of 335-350 oC (Rose & Staniland, 1982.).
Figure â€Ž3.2 Condensation of 4,4-Difluorodiphenyl ketone/Difluorobenzophenone (DFB) with Hydroquinone ƒ PEEK
Table 3.1 illustrating the main Monomers for PAEK; further, table 3.2 showing how some of these monomers are combined to produce the main classes of PAEK through nucleophilic process.
Table â€Ž3.1 Monomers for PEK and PEEK (Fink, 2008)
Hydroxy Functional Monomer
Halogen Functional Monomer
4,4`-Difluorodiphenyl ketone/ Diflurobenzophenone (DFB)
Bisphenol A, and 4_-hydroxy phenyl-4-hydroxybenzoate
4,4`-Difluorodiphenyl ketone (Kumpf, Wicks, Nerger, Pielartzik, & Wehrmann., 1982)
4,4`-Dichlorodiphenyl sulfone (Rose & Staniland, 1982.)
1,5-Bis-(4-(4`-fluorobenzoyl)-phen- oxy)-naphthalene (1,5-BFPN)
4,4`-Difluorodiphenyl ketone6 (Ben-Haida, Colquhoun, Hodge, & Williams., 2006)
(4-(4`-Trifluoromethyl)phenoxyphen- yl)hydroquinone and hydroquinone
4,4`-Difluorodiphenyl ketone (Niu, Zhu, Liu, Zhao, Wang, & Jiang., 2006)
Table â€Ž3.2 Nucleophilic Routes to some of the common classes of PAEK
*DFB + *HQ ƒ PEEK
*DFB + *DHB ƒ PEK
*DFDK + HQ ƒ PEEKK
*DFDK + DHB ƒ PEKEKK
*DFDK + DHDK ƒ PEKK
*The abbreviation used in table 3.2 are 'DFB' Diflurobenzophonne, 'DFDK' Difluorodiketone, 'HQ'Hydroquinone, 'DHB' Dihydroxybenzophenone, 'DHDK' Dihydroxydiketone
However, Jilin University and Chiba Institute of Technology (Kemmish, 2010) investigated five kinds of PAEK's having para-substituted linear molecular chains, synthesized via nucleophilic substitution reaction of the corresponding difluoro and dihydroxy compounds.
In Table 3.3 thermal transitions of various classes of PAEK are tabulated. The Tg and Tm measured through DSC (Shibata, Yosomiya, Wang, Zheng, Zhang, & Wu, 2003). On the other hand, this ratio does not affect the crystal structure of the PAEKs.
Table â€Ž3.3 Thermal transitions of various kinds of PAEK (Shibata, Yosomiya, Wang, Zheng, Zhang, & Wu, 2003)
In paper, (Yin, Zhang, Liew, & Wu, 2008), synthesized, PEEK by nucleophilic substitution reaction; with the yield of 96.1% using sulfonate as the solvent and reaction time of 55 sec - The process involves reaction of 4,4'-difluorobenzophenone (DFB) with hydroquinone (HQ) in the presence of anhydrous potassium carbonate (K2CO3) under microwave (MW) irradiation. Formed Product is realized by different analytical equipments, showed excellent thermal stability at about 563 oC in nitrogen with weight loss of 10%.
The electrophilic route involves the use of Friedel-Crafts catalysts. AlCl3 is used as a catalyst for the polymerization of p-phenoxybenzoyl chloride as such, or p-phenoxybenzoyl chloride or terephthaloyl chloride and 1,4-diphenoxybenzene to give a PEK. A PEEK is obtained by the use of p-phenoxyphenoxybenzoyl chloride, respectively.8 The process is carried out at low temperatures, such as 0-30°C. Due to the heterogeneous nature of this reaction, generally undesirable lower molecular weight polymers are produced.
Capping agents, are added to the polymerization reaction medium to cap the polymer on at least one end of the polymer chain. This terminates continued growth of that chain and controls the resulting molecular weight of the polymer, as shown by the inherent viscosity of the polymer.
Preferred nucleophilic capping agents are 4-chlorobiphenyl, 4-phenoxybenzophenone, 4-(4-phenoxyphenoxy)benzophenone, biphenyl, and 4- benzenesulonylphenyl phenyl ether. The PEEK obtained by this process shows a high degree of branching. These structural defects lead to a lowering of the melting point from greater than 330°C to 315-320°C.12
The addition of an appropriate comonomer, such as diphenoxybenzene, suppresses the xanthydrol end group content somewhat and improves the melt stability. Thus, higher diphenoxybenzene contents increase the thermal stability.
It has been found that not only is the nature of the repeat unit critical, in order to obtain good thermal and mechanical properties, but the nature of the end group is also critical for attaining desired thermal stability.12 By manipulating the end groups, it is possible to prepare PEEK structures that show still better thermal stability. Non-reactive end groups effect a better thermal stability and melt processing. End capping is achieved with an aromatic compound like benzene, toluene, xylene, phenol, anisole, diphenyl ether.
Ether Functional Monomer
Terephthaloyl chloride and
Multi Functional Monomer
In early to mid 70's, Raychem Corp. commercially introduced a poly (aryletherketone) called Stilan®. In this polymer, each ether and keto grouop is separated by 1,4-phenylene units. In 1978 imperial chemical industries PLC (ICI) commercialized a poly (aryletherketone) under the trademark Victrex® PEEK (Fink, 2008)
Although other manufacturers introduced pilot plant developments of competitive polyetherketones through the 1980s, notably BASF with PEKEKK,13 DuPont with PEKK14 and Hoechst with PEEKK,15 PEEK proved to be the only polymer to survive and prosper in an expanding range of applications through the 1990s. The technical dif¬culty of polymerising and the high cost of purifying polyetherketones to a quality suitable for processing into ¬ner components has limited competition. PEEK is now well established with a long development lead-time advantage over other polyetherketones. It is principally produced by Victrex Ltd - an independent company formed from the break-up of ICI Advanced Materials in 1993.
PEEK ¬bre-performance factors
As an introduction to the general bulk properties of PEEK as a thermoplastic material, Table 8.5 will be a useful reference.
The general factors which characterised the acceptance and underpinned the successful growth of PEEK as a new thermoplastic material can be set out brie¬‚y as:
Temperature performance: a continuous operating temperature for many applications of up to 260 °C, with short excursions to 300 °C being possible, and a non-brittle low temperature performance down to -60°C.
Chemical inertness: it is unaffected by high-temperature steam and most ¬‚uids and chemical reagents. However, it is dissolved by concentrated sulphuric acid (>50%) and degraded by strong oxidising agents such as nitric acid.
Abrasion resistance: it has a tough, low friction, low wear, cut-resistant surface and is particularly good at resisting abrasion at elevated temperatures and relatively high surface speeds.
Dimensional stability: it exhibits low creep and low shrinkage, especially below its Tg (143°C). It has excellent dynamic recovery and ¬‚ex fatigue performance.
Polymer purity: ¬bres are exceptionally pure, without the need for stabilising additives, and they have EEC and FDA approval for medical and food-contact use.16,17 A good low surface energy self-cleaning characteristic minimises contamination in use.
Flammability: ¬bres are self-extinguishing with an LOI of 35% while emitting one of the lowest levels of smoke and toxic gases.
Processability: the room temperature physical properties of PEEK ¬bres are similar to those of both polyester and nylon, so textile processes such as weaving and braiding can be conveniently performed.
Sustainability: recovery and recycling of PEEK as a material can be carried out under certain conditions with little loss of key physical properties.18
Beige (thick section)
Golden (thin section)
Melting point, Tm, °C
Glass transition, Tg, °C
Moisture regain, 65% rh 20 °C, %
Dielectric strength, kV/cm
5 ¥ 1016
Heat capacity, kJ/kg/°C
Thermal conductivity, W/m/°C
Starting in the early 1980s, a number of companies set out to produce PEEK ¬bres of various different types for commercial sale. Initially, circular cross-section mono¬laments in the diameter range 0.4 to 1.0mm were extruded at high temperature, cooled, drawn and relaxed to give low-shrinkage products with physical properties in the range 0.3 to 0.4N/tex tenacity and 30 to 40% extension-to-break, with hot-air shrinkages below 2% at 180°C.
By the mid-1980s the polymer quality had improved suf¬ciently to allow multi¬lament products in the range 5 to 15 dtex per ¬lament to be viably produced. These, depending on the process employed, could be spun with tenacities up to 0.65 N/tex at extensions below 25% and shrinkages below 1% at 180 °C. Modulus values at about 4 to 5 N/tex are typically intermediate between similar polyester and polyamide products.
Finer and heavier mono¬laments were also developed, with some specialist products in the 0.2 to 0.3 mm range having tenacities up to 0.60 N/tex at extensions below 20%, and some of the larger diameter products being made with higher shrinkages at about 10% so that they could be conveniently heat-set into spiral structures in subsequent processing.
The ¬rst crimped ¬lament staple products with a ¬neness range from 3 to 25 dtex and staple lengths of 40 to 80 mm were also developed at this time. Finer individual mono¬ls and progressively ¬ner multi¬lament yarns down to 100 dtex and ¬lament ¬nenesses of 3dtex (20 mm) have been re¬ned through the 1990s, yielding further improvements in tenacity. Additionally, a wider range of cross-sectional types, including rectangular and hollow ¬laments and an increasing range of colour pigmented mono¬laments, have become available for the main mono¬l diameters (0.20 to 1.50 mm).
The manufacturer with the most comprehensive range of PEEK ¬bre products through this period has been ZYEX Limited.19 Other producers, such as Teijin, Kosa, Shakespeare, Luxilon and Albany International, have at different times been active in different segments of the PEEK ¬bre business but none other than ZYEX has yet attempted to cover more than a small part of the potential product range.
The value of PEEK ¬bre products does not normally lie in their measured starting properties or with their short-term performance. As has been indicated, PEEK mono¬ls, yarns and ¬bres are in fact similar to polyester or nylon products in these respects. It is rather PEEK's ability to retain useful properties at an extreme condition or throughout an extended working life that differentiates it from mainstream industrial ¬bres.
The thermal, chemical and abrasive endurance of PEEK sets it apart from comparable industrial ¬bres, as is indicated in the following tables. This is especially true in real industrial processing situations where a combination of these factors, rather than just one, may be causing standard materials to fail prematurely.
Table 8.6 shows the resistance to hot air exposure over a 28-day period, and Table 8.7 the ability of PEEK ¬bres to withstand steam for 7 days. Clearly, PEEK can perform well at temperatures up to 300°C in both dry air and steam, thus indicating its oxidation and hydrolysis resistance.
Table 8.6 PEEK and other ¬bres exposed to elevated temperatures for 28 days in air
Table 8.7 PEEK and other fibres exposed for 7 days in pressurised steam
Table 8.8 Cycles to failure for PEEK and other fibres as threads - thread on thread abrasion at 120°C loaded at 0.05 cN/tex
Its resistance to abrasion is also superior to many competing ¬bres, as Table 8.8 shows.
Table 8.9 ranks the chemical resistance of PEEK ¬bres at three different temperatures. Generally, the most common or the most potentially vulnerable situations have been covered. It is probable that a 'no attack' category is very likely for other chemical situations, but, if in doubt, the latest technical data should be consulted.20
Applications relate to industrial and technical end-uses where a combination of good physical properties and inertness to the environment are essential features:
Process conveyor belts:
The mainstream application for PEEK ¬bres is in industrial conveyor belts that carry product through aggressive processing stages effectively on a continuous basis, in particular, in the manufacture of paper or nonwoven fabric products where pressing, bonding or drying stages can involve temperatures up to 300°C at line speeds up to 300m/min. In some situations, signi¬cant ¬‚ex and surface abrasion is also experienced by the conveyor belt as it passes around pulleys and drive rolls, or through nip restrictions. Here again, PEEK belts may well deliver cost-effective increases in life expectancy or process ¬‚exibility when compared with other high-tech ¬bre or steel belts.
Initially, PEEK was used in the most vulnerable part of such conveyor belts - at the joint or on the edges. Joints are often made using PEEK mono¬ls, heat-set as interlocking spirals and joined by a larger diameter straightened PEEK 'pintle pin' mono¬l. Subsequently, PEEK has been used more as a substantial part of the belt, up to 100% of the construction, products normally being woven from mono¬ls although some multi¬l yarns or needled staple felts are also used, especially in narrow
Table 8.9 The chemical resistance of PEEK ¬bres at various temperatures
Acetic acid, 10%
Hydrochloric acid, 10%
Nitric acid, 30%
Phosphoric acid, 50%
Sulphuric acid, <40%
Ethylene glycol, 50%
Methylethyl ketone (MEK)
Sodium hydroxide, 50%
Carbon monoxide (gas)
Hydrogen sulphide (gas)
Brake ¬‚uid (mineral)
Note:A = no attack, B = slight attack, C = severe attack. Where no concentration is given for the chemical it may be assumed that 100% or a saturated solution was used.
woven tape belts. Complete belts of interlocking coils are also increasingly being speci¬ed where maximising open area is important. Other industries where PEEK conveyor belts are used include textile printing and heat setting, food drying and ¬ltering and laundry ironing.
Fine woven screens of PEEK are used in frame ¬lters, or slow-moving press ¬lter applications for the production of board products or the dewatering of chemical powders. Dimensional stability and the ability to survive many more pressure cycles than equivalent metal screens are important here.
PEEK braids, made mainly from coloured/pigmented mono¬ls are increasingly important in aerospace, automotive and industrial applications. In particular, the additional chafe resistance and temperature stability delivered are ideal for electrical wiring looms associated with engine components in aircraft and motor vehicles. In addition, in any enclosed situations where toxic fumes from burning wiring could pose a threat to life, PEEK as a cable covering is ideal.
includes the wiring for robotics in nuclear installations where high levels of gamma radiation would degrade conventional plastics, and hydraulic-pressure hosing reinforcement, where the mono¬l diameters used are heavier.
Reinforced rubber gaskets
A multi¬l PEEK scrim fabric is used to reinforce synthetic rubber gaskets and bellows. The ¬bre's unique combination of good ¬‚ex fatigue performance and resistance to the chemical breakdown products of the rubber at high temperature greatly extends component lifetime in specialised applications.
Brush bristles used for hot-cleaning extruders and injection moulds are sometimes preferred as PEEK mono¬ls, rather than soft metal wires.
Multi¬l PEEK sewing threads have found niche markets in industrial protective clothing, associated with their chemical inertness. Also, hook and loop fasteners utilising both mono¬l and multi¬l PEEK products are used in quick-release garments in high-temperature environments.
The possibility of manufacturing ¬bres that exhibit deformation and rapid recovery from high stress rates has given rise to PEEK's use in up-market tennis, squash and racquet ball strings.21
The unique tonal quality and tension-holding that can be achieved from speci¬ed PEEK products have given rise to their adoption for guitar, violin and other stringed instruments.22
PEEK ¬bres can also be used as a source of the matrix in composites. Intimately mixed with carbon ¬bres, PEEK ¬bres provide an ideal feedstock for the production of advanced thermoplastic composites. In the pressurised high-temperature moulding stage, PEEK remelts and ¬‚ows to encase and protect the carbon ¬bres, becoming the matrix phase of the composite. In addition to aerospace components, medical tools and bone replacements are being made to take advantage of PEEK's excellent biocompatibility and in vitro performance
Thermoplastic polymers are not new: they have been known for a long time. It is only recently that the newer so-called high temperature or high performance thermoplastics have been introduced. The early thermoplastic polymers had predominantly aliphatic carbon backbones in which flexible carbon chains could be extended and rotated into many configurations with relative ease [4. 9. 101]. Rigidity was obtained by restricting the movement of the backbone chain either by crystallinity such as in polyethylene and polypropylene or by the introduction of side groups as in polystyrene or polymethylmethacrylate. The major limitations with these early thermoplastics which are still on the market are their low elastic modulus, low glass transition temperature (Tg) and poor solvent resistance. In the past few years, a range of thermoplastics based on aromatic polymers have been developed which surmount these limitations. The introduction of rigid aromatic rings instead of aliphatic chains increases the intermolecular forces, thus restricting the movement of the backbone chain [4, lo]. Hence, mechanical properties, high temperature capability and solvent resistance are greatly improved and can be often equivalent or even better than the best thermosets. For ease of processing, groups such as ether, carbonyl, thioether. amide, methylene. ester, isopropylidine and sulfone are incorporated between the aromatic rings to render the polymer chain more flexible 11. 10
This section deals with properties of PEEK with other high permanence polymers. The section includes the chemical structure, trade name and producers of these resins as well as their thermal and mechanical properties and solvent resistance are presented.
To be identified
Processing cycle time
The technical dif¬culty of polymerising and the high cost of purifying polyetherketones to a quality suitable for processing into ¬ner components has limited competition. PEEK is now well established with a long development lead-time advantage over other polyetherketones.
Each thermoplastic resin has its own advantages and caveats: the final selection depends mainly on the application and the cost involved.
Another trade name zyex, Textile in sports, p. 97
Overall it seems that the polyketone family offers more balanced properties. The mechanical properties in general are not exceptional but they are at least comparable to conventional thermosets; they exhibit outstanding toughness and excellenl solvent and moisture resistance and they have good melt process ability. In addition, the latest polyketones exhibit higher Tg's than the well known polyetheretherketone PEEK.
Flammability characteristics differ and can be characterized by their limited oxygen index (LOI) and spontaneous ignition temperature. The LOI index provides information about the atmospheric oxygen content at which the testing material is still combustible.
â€¢ The spontaneous ignition temperature is the lowest temperature at which the fibres burst into flames of their own accord.
â€¢ The flashpoint is the lowest temperature at which a combustible product burst into flames when approached by a pilot light.
Textile in sports, p. 97
Prices and production
Economic returns and the future
Health and environmental aspect
VICTREX UHP PEEK Driving Down
Metal Content to Less Than 1 ppm for Each Metal