Polymers storage

Polymer Thermal History Percent Double Bond Conversion for Various Polymer Storage/Treatment Conditions ... 

Figure 16.17 Polymer storage in pellet form can be done in large silos, each of which can hold 185,000 lb (7-10 hr of production). The silos can be mixed to ensure uniformity before the pellets are added to a tank car holding nearly the same amount as one silo. (Courtesy of BP Chemicals, Alvin, Texas)...

A second mechanism in the. aging of CTPB propellants also exists and proceeds concurrently with the reactions proposed above. It consists of an attack at the reactive points of unsaturation in the backbone polymer, which causes additional crosslinking and hence an increase in propellant modulus, particularly at the surface. The exposed surface of CTPB propellants changes, as indicated by an increase in hardness. Heavy metal ions are particularly harmful, and it was found that an increase from 10 to 80 p.p.m. of iron caused a significant increase in surface hardening by catalytic attack on the double bonds. Antioxidants in general provide sufficient protection for polymer storage. In CTPB propellants the antioxidant selected to protect the double bond is very important. Amine-type antioxidants have provided better surface stability than phenolic compounds. 

Another important factor that distinguishes this separation is that it is not environmentally or economically feasible to simply return a rejected stream to the environment, as in a typical aqueous RO process where the brine can be returned to the ocean. The federal regulations mandate that C02 emissions from refineries and chemical plants be reduced to low levels therefore, facilities can no longer afford to dispose of waste hydrocarbon streams in their flare systems. Pure streams from polyolefin reactors and vents from polymer-storage facilities, which were once flared, must be redirected to recovery systems. To reduce the economic penalty of environmental compliance, these paraffin and olefin mixtures must be recovered and recycled. In other words, two products must be made, a useful fuel and a useful chemical product, hence more process engineering is required in order to achieve such an objective. 

Fig. 16. Optical micrographs of decomposition structures obtained from 50/50 blend solutions containing initially 3 wt% of total polymer. Storage periods t at room temperature and annealing temperature as indicated...

Fig. 12.19. Flow diagram for the manufacture of acrylic fiber (1) acrylonitrile (2) tank farm (3) polymerizer (4) comonomer and catalyst (5) centrifuge (6) waste liquid (7) dried polymer (8) grinding (9) polymer storage (10) dissolver (11) filter (12) solvent plant (13) spinnerette (13w) wet spinning (13d) dry spinning (14) roller dryer (15) additional treatment (16) crimper (17) cutter (18) acrylic fiber bale.

Chem. Descrip. Acrylic polymer org. sol n. in IPA/acetone Uses Excipient for controlled-release pharmaceutical applies., rapidly disintegrating coatings, taste- and odor-masking Properties Liq. soi. in gastric fiuid up to pH 5, swellable and permeable above pH 5 flash pt. -15 C 12.5% polymer Storage 36 mos min. shelf life < 30 C Eudragit E 100 [Rohm GmbH Rohm Am.]... 

Chem. Descrip. Methacrylic acid copolymer Type C USP/NF Uses Excipient tor controlled-release pharmaceutical applies., enteric coated tablets masks unpleasant taste/odors of pharmaceutical ingreds. Features Sol. in intestinal tluid above pH 5.5, but resist, to gastric tluids Properties Redispersible, spray-dried powd. sol. in intestinal tluid above pH 5.5, but resist, to gastric tluids insol. in water, acids nontlamm. anionic 95% polymer Storage 36 mos min. shell lile < 30 C Eudragit NE 30 D [Rohm GmbH Rohm Am. Rohm Tech]... 

Features Superior processing general purpose polymer storage stability similar to type W shrinkage resistance similar to type WB low nerve Properties Creamy wh. chips Mooney vise. 42-52 (ML1+4,212 F) Toxicology TSCA listed... 

Studies have shown SMPs to be of crystalline nature and to be fragments of polymer crystallites, whose structure, in its turn, depends on the ways of synthesis, subsequent treatment, and polymer storage. 

Operating conditions (i) Chemical + fluid (ii) Logistics No major problems with e.g. O2, Fe, biodegradation, H2S, additive incompatibility e.g. polymer storage, mixing and injection equipment Such problems may be technically soluble but they may rule out the polymer flood on economic grounds... 

The polymer rheology in porous media is often measured by coreflooding experiments. Figure 1 shows a typical coreflooding apparatus. It is mainly composed of a pump used for pumping distilled water, piston accumulator used for polymer storage, core holder or sandpack, and pressure gauge or transducer to record injection pressure. 

Du Pont s proprietary technical information system (see Figure 1), established in 1964 and later enhanced for polymer storage and retrieval, was described in earher papers ". This corporate system supports Du Font s multidisciplinary scientific and technical efforts worldwide. It is the Company s only comprehensive index to, and collection of, documents covering Du Font s technical efforts. 

Some sequence descriptors are shown in Figure 6. Note that all eight polymers were computer-stored as (C = C C = C — C)x, because a monomer may not be repeated within a polymer storage record unless bound , e.g., as a salt or complex therefore (C = C. C = C. C = C — C)x is rejected. The sequence descriptor individualises each pol3oner. 

H. J. Coles and R. Simon, High resolution lascr-addrcsKd liquid crystal polymer storage displays, Pofymfr 26 1801 (1985). 

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