Carbon dioxide poly

Poly(carbon dioxide)-alt-(oxypropylene) poly(oxypropylene)... 

Poly(carbon dioxide-co-propylene oxide) (1 1) Poly(propylene carbonate-co-propylene oxide) (9 Poly(oxycarbonyloxy-1,2-cyclohexyleneoxy-1,2-cylclohexylene)... 

Increasingly, plastics are being used as parenteral packaging (qv) materials. Plastics such as poly(vinyl chloride), polyethylene, and polypropylene are employed. However, plastics may contain various additives that could leach into the product, such as plasticizers (qv) and antioxidants. PermeabiUty of plastics to oxygen, carbon dioxide, and water vapor must be tested in the selection of plastic containers. Furthermore, the plastic should withstand sterilization. Flaking of plastic particles should not occur and clarity necessary for inspection should be present. 

Polymers. In combination with various metal salts, sorbitol is used as a stabilizer against heat and light in poly(vinyl chloride) (qv) resins and, with a phenohc antioxidant, as a stabilizer in uncured styrene—butadiene mbber (qv) compositions and in polyolefins (see Heat stabilizers Olefin POLYMERS Rubbercompounding). Heat-sealable films are prepared from a dispersion of sorbitol and starch in water (255). Incorporation of sorbitol in coUagen films gready restricts their permeabiUty to carbon dioxide (256). 

Vinylidene Chloride Copolymer Latex. Vinyhdene chloride polymers are often made in emulsion, but usuaUy are isolated, dried, and used as conventional resins. Stable latices have been prepared and can be used direcdy for coatings (171—176). The principal apphcations for these materials are as barrier coatings on paper products and, more recently, on plastic films. The heat-seal characteristics of VDC copolymer coatings are equaUy valuable in many apphcations. They are also used as binders for paints and nonwoven fabrics (177). The use of special VDC copolymer latices for barrier laminating adhesives is growing, and the use of vinyhdene chloride copolymers in flame-resistant carpet backing is weU known (178—181). VDC latices can also be used to coat poly(ethylene terephthalate) (PET) bottles to retain carbon dioxide (182). 

Choline is a strong base (pif = 5.06for0.0065-0.0403 Afsolutions ) (3). It crystallizes with difficulty and is usually known as a colorless deHquescent sympy hquid, which absorbs carbon dioxide from the atmosphere. Choline is very soluble in water and in absolute alcohol but insoluble in ether (4). It is stable in dilute solutions but in concentrated solutions tends to decompose at 100°C, giving ethylene glycol, poly(ethylene glycol), and trimetbylamine (5). 

Table 15.4 illustrates that though the nitrile resins had a gas permeability much higher than has poly(acrylonitrile) the figures for oxygen and carbon dioxide are much lower than for other thermoplastics used for packaging. 

Figure 6.3 Conparlson of the separation of the octylphenol poly(ethylene glycol) ether, Triton X-16S on a packed column, left, and an open tubular column, right, using UV detection. For the packed column separation al0cmx2mmI.D. column packed with Nucleosil C g, d. 3 micrometers, temperature > 170 C, and mobile phase carbon dioxide (2 ml/min] and methanol (0.15 nl/rnin). pressure programmed from 130 to 375 bar in 12 min were used. For the open tubular column separation a 10 m x 50 micrometers I.O., SB-Biphenyl-30, temperature = 175°C, mobile phase carbon dioxide (0.175 ml/min) and 2-propanol (0.0265 ml/min) pressure programmed, 125 bar for 5 min, then ramped from 125 to 380 bar over 19.5 min, and held at 380 bar for 15 min. were used. (Reproduced with permission from ref. 57. Copyright Preston Publications, Inc.) ...

Figure 6.9 Separation of a poly(styrene) oligomer mixture of 2000 average molecular weight by open tubular column SFC using a linear density program (A) and an asymptotic density progreua in (B) with carbon dioxide as the mobile phase. (Reproduced with permission from ref. 115. Copyright Preston Publication, Inc.)...

Urethane hydrolyzes into an amine, an alcohol, and carbon dioxide. So the possible degradation products of a poly(phosphoester-urethane) are diamines, diols, phosphates, carbon dioxide, and even ureas. Urea is possible because the isocyanate is extremely sensitive to moisture, which would convert the isocyanate to an amino group. One is therefore bound to have traces of diamine in the polymerization that leads to a urea bond in the backbone. We think the cytotoxicity seen in the macrophage functional assay comes from the TDI structure. 

Polyesters, such as microbially produced poly[(P)-3-hydroxybutyric acid] [poly(3HB)], other poly[(P)-hydroxyalkanoic acids] [poly(HA)] and related biosynthetic or chemosynthetic polyesters are a class of polymers that have potential applications as thermoplastic elastomers. In contrast to poly(ethylene) and similar polymers with saturated, non-functionalized carbon backbones, poly(HA) can be biodegraded to water, methane, and/or carbon dioxide. This review provides an overview of the microbiology, biochemistry and molecular biology of poly(HA) biodegradation. In particular, the properties of extracellular and intracellular poly(HA) hydrolyzing enzymes [poly(HA) depolymerases] are described. 

Poly(HA) can be biodegraded to water and carbon dioxide or methane by a large variety of ubiquitous microorganisms present in many ecosystems (Fig. 1). This fairly easy bio degradability came as a surprise given the inertness of the water-insoluble, hydrophobic, and (partially) crystalline polymers. 

Kawabata Y., Kamichika T., Imasaka T., Ishibashi N., Fiber-optic sensor for carbon dioxide with a pH indicator dispersed in a poly(ethylene glycol) membrane, Anal. Chim. Acta 1989 219 223. 

American scientists prepared the organo-silica sol-gel membranes60 and demonstrated in a single layer format for pH measurement and multiple-layer format for both C02 and NH3. The sensors used a hydroxypyrenetrisulfonic acid (HPTS) as the indicator immobilizes in a base-catalyzed sol-gel containing poly(dimethyl)siloxane, aminopropyl-triethoxysilane (APTES) and tetraethylorthosilicate (TEOS). This indicator gel was over coated with a hydrophobic sol-gel to reduce cross reactivity to pH when either carbon dioxide or ammonia were examined. 

In 1968, a French Patent issued to the Sumitomo Chemical Company disclosed the polymerization of several vinyl monomers in C02 [84], The United States version of this patent was issued in 1970, when Fukui and coworkers demonstrated the precipitation polymerization of several hydrocarbon monomers in liquid and supercritical C02 [85], As examples of this methodology, they demonstrated the preparation of the homopolymers PVC, PS, poly(acrylonitrile) (PAN), poly(acrylic acid) (PAA), and poly(vinyl acetate) (PVAc). In addition, they prepared the random copolymers PS-co-PMMA and PVC-co-PVAc. In 1986, the BASF Corporation was issued a Canadian Patent for the preparation of polymer powders through the precipitation polymerization of monomers in carbon dioxide at superatmospheric pressures [86], Monomers which were polymerized as examples in this patent included 2-hydroxyethylacrylate and iV-vinylcarboxamides such as iV-vinyl formamide and iV-vinyl pyrrolidone. 

De Simone et al. synthesized poly(fluoroalkyl acrylate)-based block copolymers for use as lipophilic/C02-philic surfactants for carbon dioxide applications [181]. The particle diameter and distribution of sizes during dispersion polymerization in supercritical carbon dioxide were shown to be dependent on the nature of the stabilizing block copolymer [182]. 

A unique methodology for the generation of nanoporous thin films using supercritical carbon dioxide (SCCO2) for potential nanolithographic applications was introduced in 2004 by Li et al. [53]. In this work, thin films of PS-poly(perfluorooctylethyl methacrylate) [PFMA] were spin-cast onto sili-... 

Gamma radiolysis of simple carboxylic acids and N-acetyl amino acids results in loss of the carboxyl group with formation of carbon monoxide and carbon dioxide. In the carboxylic acids, the ratio of C0/C02 produced is approximately 0.1, while in the N-acetyl amino acids the ratio is much smaller. In the poly carboxylic acids and poly amino acids, radiolysis also results in the loss of the carboxyl group, but here the ratio of C0/C02 is greater than 0.1. Incorporation of aromatic groups in the poly amino acids provides some protection for the carboxyl group. The degradation of the poly acids is believed to involve radical and excited state pathways. 

Table VII. G-values for carbon monoxide and carbon dioxide formed on radiolysis of poly acids at 303 K...

As with the aliphatic carboxylic acid model compounds, the major volatile product observed on gamma radiolysis of the poly acids is carbon dioxide. However, the carbon dioxide yields are somewhat larger than those observed for the model compounds. 

Carbon monoxide was also observed in significant yields for each of the poly acids and the ratio of G(C0)/G(C02) was found to be approximately three times greater than that found for the small molecule model compounds. This suggests that the processes involved in the formation of carbon monoxide and carbon dioxide are both more efficient in the poly acids. 

For each of the poly carboxylic acids investigated, the sum of the yields of carbon monoxide and carbon dioxide is much larger than the yield of radical products. This observation differs from that noted for the model compounds, where the two were of similar magnitude. This suggests that excited state processes may play a more significant role in the degradation of the poly acids than they do in the small molecule, model compounds. 

In the poly carboxylic acids, carbon dioxide is the major product of radiolysis, but the carbon monoxide yields are greater than they are for the aliphatic carboxylic acids. However, the radical yields are not greater than expected on the basis of the model compounds, which suggests that excited states play an important role in the degradation of these poly acids. 

PEN has lower gas permeation coefficients than PET for carbon dioxide, oxygen and moisture for both film types. Although the gas-barrier properties of PEN are similar to those of poly(vinyl dichloride), it is not affected by moisture in the environment. Both oriented and unoriented PEN films restrict gas diffusion more... 

Amination (11) and solution carbonation (8) reactions were carried out as described previously. For solid-state carbonations, a benzene solution of poly(styryl)lithium was freeze-dried on the vacuum line followed by introduction of high-purity, gaseous carbon dioxide (Air Products, 99.99% pure). Analysis and characterization of polymeric amines (11) and carboxylic acids (8) were performed as described previously. Benzoyl derivatives of the aminated polystyrenes were prepared in toluene/pyridine (2/1. v/v) mixtures with benzoyl chloride (Aldrich, 99%). 

Wyman, Allen and Altares (20) reported that the carbonation of poly-(styryl)lithium in benzene with gaseous carbon dioxide produced only a 60% yield of carboxylic acid the acid was contaminated with significant amounts of the corresponding ketone (dimer) and tertiary alcohol (trimer) as shown in eq. 6. A recent, careful, detailed investigation of the carbonation of polymeric organolithium compounds has... 

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