Resin plug

Combinatorial chemistry has moved from specially centralized laboratories, often equipped with multimillion-dollar robots, onto the bench of individual medicinal chemists. This change in direction requires the availability of personal chemistry tools that are simple to operate, easy to arrange in the laboratory, and reasonably priced. Such instruments are now available for the effective synthesis of combinatorial libraries. The Encore synthesizer represents a simple and efficient personal chemistry tool that allows the execution of directed split-and-pool combinatorial synthesis. The current version of the Encore synthesizer is designed for solid-phase synthesis on SynPhase Lanterns however, it can be modified for synthesis on alternative solid supports such as resin plugs from Polymer Laboratories (e.g., StratoSpheres Plugs). 

For vitrinite reflectance (Rq) measurements, coarsely crushed samples were acidified with hydrochloric and hydrofluoric acid to remove carbonate and silicate. The solution was then centrifuged with heavy liquid to separate kerogen. The kerogen was embedded in a resin plug and polished to a flat shiny surface. Measurements of the percentage of incident light reflected from vitrinite particles under oil immersion with a Carl Zeiss MPM-03 microspectrophotometry system were made. 

Fig. 18. (a) Cross-section of a resin plug (100 x magnification) (b) single bead within the matrix of the resin plugs (270 x magnification) (c) illustration of the dimension of the resins plugs. 

Pool Technique. Resin beads are the most frequently used formulation of insoluble support for solid-phase organic synthesis. However, the yield from one typical bead (100 jam) is only about lOOpmol. The need for substantially higher yield from one unit of solid phase triggered the development of different formulations of solid support. Two different scenarios were followed compartmentalization of resin beads (T-bags, wafers, Kans, capsules, and resin plugs) and development of modular solid support (SynPhase Lanterns, rods). 

Fig. 3. Specific conductance of resin plug saturated with solution vs. specific conductance of interstitial solution (1000 Hz) [4]. Conductivity values for salt solutions marked on abscissa refer to 25 °C. 

Fig. 6. Potential difference, E between upper and lower Ag/AgCl electrode against average activity a of sodium chloride in solutions separated by cation-exchange resin plug (Dowex 50,100-200 mesh) [5]. - Solution activity ratio 3 1. Vertical lines represent potential difference measured between Ag/AgCl electrodes at 25 °C, solid line calculated from theory.

Thermoplastic Processing. Poly(ethylene oxide) resins can be thermoplasticaHy formed into soHd products, eg, films, tapes, plugs, retainers, and fillers (qv). Through the use of plasticizers (qv), poly(ethylene oxide) can be extmded, molded, and calendered on conventional thermoplastic... 

Pretreatment of aqueous streams may be required prior to using ion exchange. Suspended soHds that can plug an ion-exchange unit should be reduced to the 10 p.m level. Organics that can foul resins can be removed by carbon adsorption. Iron [7439-89-6] and manganese [7439-96-5], commonly present in ground waters, should be removed because they precipitate on the resin. 

Covers for the battery designs in Figures 1 and 2 are typically molded from materials identical to that of the respective case, and vent plugs are frequentiy made of molded polypropylene. Other combinations are possible, eg, containers molded of polyethylene or polypropylene may be mated with covers of high impact mbber for use in industrial batteries. After the cover is fitted over the terminal post, it is sealed onto the case. The cover is heat bonded to the case, if it is plastic it is sealed with an epoxy resin or other adhesive, if it is vulcanized mbber. Vent caps are usually inserted into the cover s acid fiU holes to faciHtate water addition and safety vent gasses, except for nonaccessible maintenance-free or recombinant batteries. In nonaccessible batteries, the vent is fabricated as part of the cover. 

Many larger installations also feature a batch stiU. Material to be separated may be high in solids content, or it might contain tars or resins that would plug or foul a continuous unit. Use of a batch unit can keep solids separated and permit convenient removal at the termination of the process. 

The encapsulation of electrical components provides an interesting extension to the use of plastics materials as insulators. Components of electronic systems may be embedded in a single cast block of resin (the process of encapsulation). Such integrated systems are less sensitive to handling and humidity and in the event of failure the whole assembly may be replaced using seldom more than a simple plugging-in operation. Encapsulation of miniaturised components has proved invaluable, particularly in spacecraft. 

Triacetin resistance is especially critical when filter tips are made in one location, stored, and then shipped to another location. For these operations, polyethylene-based adhesives are used because of their low polarity and therefore excellent resistance to triacetin. Where filter plugs are attached at the same location shortly after production, EVA-based adhesives are suitable and preferred. Both types of adhesives use low odor, clean tackifiers such as hydrogenated hydrocarbons or pure monomer resins (typically a-methylstyrene based). Rosin, rosin esters, and phenol-containing tackifiers are not acceptable. EVA-based adhesives use a higher level of wax (about 1 /3 of the formula) than polyethylene-based adhesives (5-20% wax) due to the lower crystallinity and slower set of EVA vs. PE. Application viscosities are 2000-5000 cP. 

Process systems handling polymers and resins (e.g., butyl rubber or ethylene-propylene diene monomer rubbers) are often subject to plugging at dead-end locations such as PR valve inlets. In extreme cases, complete blockage of inlet piping and valve nozzle can result. This problem can be eliminated by the application of a flush-seated PR valve, in which dead-end areas are eliminated by placing the valve disc flush with the vessel wall, in the flow pattern of the contents. 

Pipelines in the ground can be mortar lined in situ by the use of travelling devices. Epoxy resin paints for long welded pipelines already laid have been applied in situ by placing two plugs in the pipeline with the paint between them, and then forcing them to travel through the pipeline by the use of compressed air. 

A 50 mL or 100 mL burette, with Pyrex glass-wool plug or sintered-glass disc at the lower end, can generally be used for the determinations described below alternatively, the column with side arm (Fig. 7.4a) is equally convenient in practice for student use. Reference will be made to the Duolite resins the equivalent Amberlite or other resin (see Table 7.1 in Section 7.1) may of course be used. 

Unlike phenol-formaldehyde polymers, the amino resins are not themselves deeply coloured, but are of a naturally light appearance. They can be easily pigmented to give a variety of shades, which leads to application in uses where good appearance is highly valued, for example in decorative tableware, laminated resins for furniture, and modem white electrical plugs and sockets. 

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