PEEK compound

Corrosion resistance in subsea environments is of prime importance, as FPSO s are constructed in open water to facilitate mooring tankers at offshore oil and gas exploration stations without jetties and breakwaters. Unlike bronze components, which can develop severe galvanic corrosion, PEEK bearings and thrust washers provide longterm corrosion resistance and superior wear resistance. PEEK compound requires no external lubrication, another key advantage in this application. Bronze bearings and thrust washers are subject to premature wear and reduced service life should they run dry. (Victrex pic, Victrex Tech. Ctr., Hillhouse Int l., Thornton Cleveleys, Lancashire FY5 4QD, UK Phone +44-1253-897700 URL www. victrex.com). 

Since PPS is crystalline we should expect it to produce blends with much better chemical resistance than amorphous materials such as PAES. It should also allow very substantial cost reduction and can improve melt flow. Union Carbide filed patents on PEEK/PPS blends as early as 1982 [15]. Kureha has developed materials with improved compatibility, melt flow, formability and mechanical properties [16] Ticona has filed patents on improved PEEK/PPS blends and the most recent patent provides a good summary of the historical developments [17]. Solvay has filed patents on PEEK/PPS blends for use in bearing surfaces - under the conditions tested the blends perform as well as pure PEEK compounds [18]. It is possible that this technology is used in some of Solvay s Avaspire grades. 

Figure A2 Dynamic fatigue properties of Victrex PEEK compounds at 5 Hz and 23 °C...

PEEK compounds are molded or extruded in conventional TP equipment at 350 to 400°C (660 to 750 F). Their mold shrinkage is about 1 percent for the unreinforced and 0.1 to 1.4 percent for the reinforced grades, depending on their fiber orientation. PEEK is widely used in carbon-fiber composites because of their excellent adhesion to carbon fibers. PEEK S heat-distortion temperature is above 315°C (600°F) at 1,820 kPa (264 psi), its tensile strengths are up to 215 MPa (31,0(X) psi), and its flexural modulus is up to 2i X 10 psi. 

Table 12.5 Wear Resistance Data of Plastic Against Steel (1018 C) of RTP 2200 Series Polyetheretherketone (PEEK) Compounds, Determined by Thrust Washer Test PerASTM D3702 [6]...

Wear resistance data in metric units for RTP 2200 series polyetheretherketone (PEEK) compounds. RTP Company, . 

Another new entrant began production of PEEK compounds in 2000. Oxford Performance Materials, a division of Oxford Polymers in the UK, offers Oxpekk PEEK compounds based on copolymer base resins made by Cytec, New Jersey, USA. The compounds are distributed by Infinite Polymer Systems in the USA. 

Recently, Dutta and Maiti [21] reported nitro displacement polymerization of the bisphenol dianion with the sulfone activated dinitro aromatic compounds. In addition, there have been recent reports of the development of functionalized PEEK [22] and polyether sulfone ketone (PESK) [23] that are comparable to commercially available high performance polymers. 

The chromatographic pumps and flow path used in IEC must be resistant to corrosion. For this reason, polymers such as poly(etheretherketone) (PEEK , ICI Americas Wilmington, DE) have entered into widespread usage in ion chromatography. Electrochemical detectors may also be subject to corrosion by certain ions. This chapter will review the chromatographic materials, detectors, and applications of ion exchange chromatography. For some classes of compounds, where reversed phase or normal phase alternatives may have been developed, alternative separation techniques will be presented. 

Towflex (Hexcel Composites) is based on carbon, glass or aramid fibres impregnated with polypropylene, polyamide, PPS, polyetherimide, PEEK. Product forms include flexible Towpreg, woven fabric, braided sleeving, UD tape, chopped compression moulding compound, moulded plates, thermoformable laminates. 

Another important part of Organic 11 is carbonyl chemistry. We look at the basics of the carbonyls in Chapter 9. It s like a family reunion where 1 (John, one of your authors) grew up in North Carolina — everybody is related. You meet aldehydes, ketones, carboxylic acids, acyl chlorides, esters, cimides, and on and on. It s a quick peek, because later we go back and examine many of these in detail. For example, in Chapter 10 you study aldehydes and ketones, along with some of the amines, while in Chapter 11 we introduce you to other carbonyl compounds, enols and enolates, along with nitroalkanes and nitriles. 

An HPLC column is a straight, stainless steel calibrated tube (sometimes coated on the inside with an inert material such as glass or PEEK 5 ) between typically 3 and 25 cm in length. The internal diameter of the column can vary from 0.5 to 5 mm (Fig. 3.6). The stationary phase is held in the column by one porous disc at each extremity. Dead volumes within the column are kept as small as possible. The flow of the mobile phase into the column must not exceed a few ml/min. Some manufacturers offer microcolumns that have an internal diameter in the order of 0.3 mm and are 5 cm in length. Typical mobile phase flow rates for these narrow columns can be as low as a few pl/min. Because complete elution of compounds with these microcolumns requires only a few drops of mobile phase, the stationary phase and pumps have to be adapted accordingly. These narrow columns not only substantially reduce the amount of mobile phase which has to be used but also improve resolution by diminishing the diffusion inside the column. They are well suited for HPLC-MS (cf. Chapter 16). 

Samples, even at moderate concentrations, injected into the HPLC column may precipitate in the mobile phase or at the column frit. In addition, the presence of other compounds (e.g., lipids) in the injection sample may drive the carotenoids out of solution or precipitate themselves in the mobile phase, trapping carotenoids. It is best to dissolve the sample in the mobile phase or a slightly weaker solvent to avoid these problems. Centrifugation or filtration of the samples prior to injection will prevent the introduction of particles that may block the frit, fouling the column and resulting in elevated column pressure. In addition to precipitation, other sources of on-column losses of carotenoids include nonspecific adsorption and oxidation. These can be minimized by incorporating modifiers into the mobile phase (Epler et al., 1993). Triethylamine or diisopropyl ethylamine at 0.1% (v/v) and ammonium acetate at 5 to 50 mM has been successful for this purpose. Since ammonium acetate is poorly soluble in acetonitrile, it should be dissolved in the alcoholic component of the mobile phase prior to mixing with other components. The ammonium acetate concentration in mobile phases composed primarily of acetonitrile must be mixed at lower concentration to avoid precipitation. In some cases, stainless steel frits have been reported to cause oxidative losses of carotenoids (Epler et al., 1992). When available, columns should be obtained with biocompatible frits such as titanium, Hastolloy C, or PEEK. 

Mikl, O., and J. Peek The Determination of Chlorine in Organic Compounds. Chem. Listy 46, 382 (1952). 

Figure 7.2.12 shows the principal set-up for this experiment. The column, containing the immobilized free radicals consists of an adapted PEEK tube, which fits into the flow probe below the detection cell. Figure 7.2.13 depicts a spectrum of d-n-butylphthalate recorded under the influence of a ( free-radical ) column filled with 2,2,6,6-tetramethylpiperidin-l-oxyl (TEMPO), immobilized with an aminopropyl spacer on silica. The spectrum is taken from an on-line separation of a two-compound mixture. The line width is of the same order as... 

The use of ICP-MS provides some important benefits when coupled to an HPLC that separates As species prior to measurement. ICP-MS has fit-for-purpose limits of detection (LoDs) thus, analytical, not preparative, separation systems can be used with a high sampling rate ( 1 ms) in order to measure transient signals and to separately quantify closely eluting compounds from HPLC. HPLC-ICP-MS coupling can be achieved simply via a 50 cm piece of PEEK tubing without loss of peak resolution, whereas chromatographic flow rates are compatible with conventional ICP-MS spray chambers. 

Figure 11-14. Eight-channel parallel LC-MS system consisting of Shimadzn gradient HPLC pumps, a Gilson 215 multiple probe autosampler, an AB/MDS-SCIEX API165 mass spectrometer equipped with a TurboIonSpray ion sonrce, eight Peeke Scientific microbore columns (10-mm x 1-mm-i.d., 3-pm HQ-C18), and a Valeo switching valve. The volume of the sample loops is 20 pL, and full loop injections were used for all experiments. Total mobile-phase flow rate is 2.0mL/min (0.25mL/min for each column). The eight-channel LC-MS system allows up to four plates of compounds (or 4 X 1152 samples) to be run in a single day.

Adsorption or chemisorption on column packing or on different hardware components. Increase mobile phase strength add competing base (for basic compounds) or use base-deactivated packing ensure no reactive groups are present use inert tubing and flow-path components, e.g., PEEK. 

Pyrolysis studies on PEEK by thermogravimetry/MS and Py-GC/MS were reported in literature [7], The compounds described to be generated in the Py-GC/MS experiment, which was performed at 971° C, are shown in Table 9.3.2. 

PK. [Compounding Tech.] PEEK, some glass or carbon rcinforc ... 

Fig. 22. Gw chromatogram of an axtract of mariiuana. 1 it CBD 2 it -THC 3 it CBN. In thit procadura a tmall amount of the liquid extract it injected into a long heated coil through which gat pattes. The thoutands of compound leave the column at different tirrtw and are detected and dispiayad w a terie of irregular peek taan above. Injection of known ttandardt allow identification of the peaks.

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