Polyethylene extraction

Hsiao et al. [11] have studied the use of MALDI ionisation for the detection of antioxidants and hindered amine light stabilisers (HALS) in polyethylene extracts. Using 2,5-dihydroxybenzoic acid as matrix, diagnostic spectra were obtained on standards, but the presence of soluble low molecular weight polyethylene in extract solutions caused some problems with ionisation suppression. 

Apparatus end-over-end shaker, centrifuge, 0.45 pm membrane filter, polyethylene extraction bottles (200 mL), polyethylene bottles (50 mL)... 

Convert the optical density obtained from the polyethylene extract to milligram Santonox R by means of the calibration graph. Calculate the Santonox R content of the polyethylene as follows ... 

N = Weight (g) of Santonox R in 10 cm polyethylene extract obtained by referring determined optical density to the calibration graph. 

Alcoholic solutions of iron (III) chloride are reduced photochemically at an appreciable rate upon exposure to daylight. Reaction of the polyethylene extract with ferric chloride and 2,2 -dipyridyl reagents is carried out, therefore, in black painted... 

Inspect the plate under ultraviolet light (254 nm) and compare the intensity of the Santonox R spot from the polyethylene extract with the intensities of the standard spots. If the spot is of lower intensity than that of the 0.03% w/v standard than a new chromatogram should be developed using standards, 0.025%, 0.015% and 0.005% w/v of Santonox R in chloroform. 

Visually compare under an ultraviolet lamp the intensity of the spot from the polyethylene extract with the standard spots and thus estimate the percentage level of Santonox R in the chloroform solution. Spray the thin-layer plate with a 2% w/v ethanol solution of 2,6-dibromo-p-benzoquinone-4-chlorimine. Allow the thin-layer plate to dry and re-spray using a 2% w/v aqueous solution of borax. Re-estimate the amount of Santonox R present in the chloroform solution by visually comparing the purple spots produced. 

Pipette 20 cm of the polyethylene extract into a 25 cm volumetric flask. Pipette in 2 cm ethanol and 2 cm hydrogen peroxide reagent and adjust the solution temperature to 25 + 3°C and make up to the 25 cm mark with ethanol and mix well. 

Figure 6.8 Homogeneous nucleation rates for polyethylene extracted from measurements on bulk E/VCH 5/22 ( ), bulk E/SEB 9/55 ( ), and a suspension of linear polyethylene droplets ( , data of Koutsky et al. [1967]). Slopes S of log(rate) vs. 7/ are indicated for each of the three data sets. Inset shows the same data plotted on an expanded rate scale, with the prediction of classical nucleation theory shown as the solid curve (prediction uses the material parameters given by Koutsky et al. [1967]).

Sintering has been used to produce a porous polytetrafluoroethylene (16). Cellulose sponges are the most familiar cellular polymers produced by the leaching process (123). Sodium sulfate crystals are dispersed in the viscose symp and subsequently leached out. Polyethylene (124) or poly(vinyl chloride) can also be produced in cellular form by the leaching process. The artificial leather-tike materials used for shoe uppers are rendered porous by extraction of salts (125) or by designing the polymers in such a way that they precipitate as a gel with many holes (126). 

Analytical and test methods for the characterization of polyethylene and PP are also used for PB, PMP, and polymers of other higher a-olefins. The C-nmr method as well as k and Raman spectroscopic methods are all used to study the chemical stmcture and stereoregularity of polyolefin resins. In industry, polyolefin stereoregularity is usually estimated by the solvent—extraction method similar to that used for isotactic PP. Intrinsic viscosity measurements of dilute solutions in decahn and tetraHn at elevated temperatures can provide the basis for the molecular weight estimation of PB and PMP with the Mark-Houwiok equation, [rj] = KM. The constants K and d for several polyolefins are given in Table 8. 

Nylon-6 [25038-54-4] (9) is made by the bulk addition polymerization of caprolactam. Monofilament Nylon-6 sutures are avadable undyed (clear), or in post-dyed black (with logwood extract), blue (ED C Blue No. 2), or green (D C Green No. 5). Monofilament nylon-6 sutures are sold under the trade names Ethilon and Monosof monofilament nylon-6,6 sutures, under the trade names Dermalon and Ophthalon and monofilament polyethylene terephthalate sutures, under the trade name Surgidac. 

Stratifying water systems for selective extraction of thiocyanate complexes of platinum metals have been proposed. The extraction degree of mthenium(III) by ethyl and isopropyl alcohols, acetone, polyethylene glycol in optimum conditions amounts to 95-100%. By the help of electronic methods, IR-spectroscopy, equilibrium shift the extractive mechanism has been proposed and stmctures of extractable compounds, which contain single anddouble-chai-ged acidocomplexes [Rh(SCN)J-, [Ru(SCN)J, [Ru(SCN)J -have been determined. Constants of extraction for associates investigated have been calculated. 

A suspension of 17a,21-dihydroxypregna-4,9(ll)-diene-3,20-dione 21-acetate (0.77 g) and iV-bromoacetamide (0.3 g) in anhydrous methylene dichloride (40 ml) is added over 2-3 min with stirring to a mixture of anhydrous hydrogen fluoride (10.19 g), and anhydrous tetrahydrofuran (18 g) in a polyethylene bottle at —80° (acetone-dry ice). After 1 hr at —80° the reaction mixture is kept for a further 1 hr at 0° and then added cautiously to an excess of an ice-cold solution of sodium carbonate. Extraction with methylene dichloride and crystallization from acetone-hexane furnish 9a-bromo-ll -fluoro-17a,21-dihydroxypregn-4-ene-3,20-dione 21-acetate (0.69 g), mp 205-208°, raised by several crystallizations from acetone-hexane to 215-217° [aju 142° (CHCI3) max 240-242 mju (e 15,500). 

Preparation of 9a-Fluoro-110,17a,21-Trihydroxy-160-Methyl-4-Pregnene-3,2O-Dione 21-Acetate To a solution of 200 mg of 9(3,11(3-epoxy-1 7a,21-dihydroxy-16(3-methyl-4-pregnene 3,20-dione 21-acetate in 2 ml of chloroform and 2 ml of tetrahydrofuran in a polyethylene bottle at -60°C was added 2 ml of a 2 1 (by weight) mixture of anhydrous hydrogen fluoride and tetrahydrofuran. After 4 hours at -10°C the mixture was cooled to -60°C and cautiously added to a stirred mixture of 30 ml or 25% aqueous potassium carbonate and 25 ml of chloroform kept at -5°C. The aqueous phase was further extracted with chloroform and the latter phase washed with water and dried over magnesium sulfate. The residue on crystallization from acetone-ether gave pure 9a-fluoro-11(3,17a,21-trihydroxy-16(3-methyl-4-pregnene-3,20-dione 21-acetate. 

To approximately 1.3 g of hydrogen fluoride contained in a polyethylene bottle and maintained at -60°C was added 2.3 ml of tetrahydrofuran and then a solution of 500 mg (0.0012 mol) of 6a-fluoro-9/3,11/3-epoxy-16a-methyI-17a,21 -dihydroxy-1,4-pregnadiene-3,20-dione-2T acetate in two ml of methylene chloride. The steroid solution was rinsed in with an additional 1 ml of methylene chloride. The light red colored solution was then kept at approximately -30°C for 1 hour and at -10°C for 2 hours. At the end of this period it was mixed cautiously with an excess of cold sodium bicarbonate solution and the organic materiai extracted with the aid of additional methylene chloride. 

Figure 8. Polyethylene separator production process (II) Extraction...

The alternative is hexane, which because of the explosion hazard requires a more expensive type of extractor construction. After the extraction the product is dull gray. The continuos sheet is slit to the final width according to customer requirements, searched by fully automatic detectors for any pinholes, wound into rolls of about 1 m diameter (corresponding to a length of 900-1000 m), and packed for shipping. Such a continuous production process is excellently suited for supervision by modern quality assurance systems, such as statistical process control (SPC). Figures 7-9 give a schematic picture of the production process for microporous polyethylene separators. 

In this connection the remaining oil in the separator plays an important role. At the first glance, to increase the porosity a total extraction of the oil would be expedient, but certain oil components have been shown to exert a protective action on the polyethylene. Oil content and its distribution, as well as selection of the oil, thus gain particular significance [41, 52-54]. 

Extraction for enzyme recovery is a common process. Polyethylene glycol-dextran mixture is used to recover a-amylase from fermentation broth. Given a partition coefficient of 4.2, calculate the maximum enzyme recovery when... 

Chlorinated polyethylene CPEs provide a very wide range of properties from soft/ elastomeric to hard. They have inherent oxygen and ozone resistance, have improved resistance (compared to PEs) to chemical extraction, resist plasticizers, volatility, and weathering. Products do not fog at high temperatures as do PVCs and can be made flame retardant. 

A prehminary study of the use of larch AGs in aqueous two-phase systems [394] revealed that this polysaccharide provides a low-cost alternative to fractionated dextrans for use in aqueous two-phase, two-polymer systems with polyethylene glycol (PEG). The narrow molecular-weight distribution (Mw/Mn of 1-2) and low viscosity at high concentration of AG can be exploited for reproducible separations of proteins under a variety of conditions. The AG/PEG systems were used with success for batch extractive bioconversions of cornstarch to cyclodextrin and glucose. 

Fig. 11 Experimental set-up for small-scale microwave SPPS of /S-peptides (SPE = solid-phase extraction). 1 Pasteur pipet for N2 agitation 2 10 mL glass vial 3 4mL solid-phase extraction tube 4 DMF 5 coupling solution 6 resin 7 polyethylene frit 8 Luer-lock cap...

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