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Polyvinyl chloride sequences

Seven other possible pentad sequences (mmmr, rrmr, mmrm, mmrr, mrmr, mrrm, and rmmr) are atactic. Residues R may be CH3 for polypropylene, C6H5 for polystyrene, Cl for polyvinyl chloride, CN for polyacrylonitrile, and C02CH3 for polyacrylic acid methyl ester. [Pg.309]

Polyenes exhibit two strong Raman bands between 1600 and 1500 cm and between 1200 and 1100 cm , respectively. These are attributed to in-phase vibrations of the C=C and C-C bonds, respectively, throughout the entire chain. Examples include all-trans-retinol (Fig. 4.1-6B), /3-carotene, and carotene-containing proteins, obtained, for instance, from lobster shells (Rimai et al., 1973 Oseroff and Callender, 1974). Polyene sequences with approximately twenty conjugated double bonds, formed by HCl elimination from polyvinyl chloride as a result of aging, also show these Raman bands at 1495 and 1115 cm (Peitscher and Holtrup, 1975). These bands are enhanced as a consequence of the resonance Raman effect, which makes it possible to detect such groups in polymers and natural materials, even at low concentration. [Pg.199]

Polyvinyl chloride (PVC) is an economical thermoplastic film with good barrier properties to gases and water. Later developments of even higher barrier Saran type resins based on copolymers of vinylidene chloride and vinyl chloride produced many new packaging opportunities. These materials are still very popular today (37-39). Consideration of the structure-permeability relationships for the Saran materials in Chapter 6(40) indicates that their evolution is still continuing as better understanding of the influence of sequence distribution and even more subtle issues of chain microstructure emerge. [Pg.8]

Even more popular than dot blots are microtiter plate assays, so-called ELlSAs (enzyme-linked immunosorbent assay), in which antibody or antigen is loaded into the depression of polyvinyl chloride or polystyrene plates (Kemeny 1994). The depressions are then further coated with antibody, antigen, and enzyme-conjugated antibody in a defined sequence. The antigen is detected via an enzymatic color reaction (Table 6.2). Many companies (Nunc, Flow, Costar, Falcon) offer a palette of products such as 8- or 12-channel pipettes, automatic washing devices, ELISA readers, and so on that make life easier for the friends of ELISA. [Pg.152]

The existence of an absorption at around 1430-1420 cm indicates the presence of an a-methylene (sometimes known as an active methylene), adjacent to the ester or ketone carbonyl. This, in conjunction with the presence of a normal aliphatic methylene sequence (1450-1470 cm ) differentiates the vinyl polymers, such as polyvinyl alcohol (PVA) and polyvinyl chloride (PVC), from compounds such as PMA and PMMA. Since this step may be confusing to the reader, it is suggested that attention is paid to the assignments for vinyl acetate-type and acrylate-type polymers. [Pg.211]

FIGURE 2.8 NMR spectra recorded for a polyvinyl chloride (PVC)-derived char. The bottom spectrum was recorded with normal CP pulse sequence, whereas a dephasing delay (x) was used for recording the top spectrum (CP/DD). Stars indicate spinning sidebands. [Pg.115]

Pyrolysis products such as benzene, toluene, styrene, and naphthalene were observed. The amount of these aromatic compounds formed directly reflects the concentration of chlorine atoms and their distribution in the CPE. The composition and structure calculations were based on those degraded trimer peak intensities obtained by Py-GC. This Py-GC method can be used to quantitatively determine the chlorine content in CPE. The same method can also explore the microstructure through number-average sequence length (NASL) of ethylene and vinyl chloride monomers. Other structure-related terms, such as the percentage of grouped vinyl chloride monomers, i.e., the percentage of chlorine atoms structured as polyvinyl chloride (PVC)-like structures, can also be calculated. [Pg.105]

CCI2 —CH2 —CHCl— sequence of the vinyl chloride-vinylidene chloride copolymer appears at 1420 cm If an increased frequency for this CH2 bending is observed for a polyvinyl-vinylidene chloride copolymer, it is interpreted as originating from a random or block copolymer [56]. The presence of the 1420 cm band suggests the random copolymerization, and a peak at 1404 cm suggests block copolymerization for the polyvinyl-vinylidene chloride system. [Pg.252]

Regioisomerism is also exhibited by other polymers, including polyvinylidene fluoride, polyvinylidene chloride [8-11], polydienes and polyvinyl acetate [12,13]. Head-to-tail and tail-to-tail sequences have been determined for polyvinylidene chloride [8-12] and polyvinyl acetate [12,13]. [Pg.272]


See other pages where Polyvinyl chloride sequences is mentioned: [Pg.3]    [Pg.543]    [Pg.555]    [Pg.280]    [Pg.266]    [Pg.266]    [Pg.463]    [Pg.315]    [Pg.153]    [Pg.55]    [Pg.80]    [Pg.416]    [Pg.63]    [Pg.111]    [Pg.168]    [Pg.566]    [Pg.274]    [Pg.1215]    [Pg.226]    [Pg.167]    [Pg.286]    [Pg.2]   
See also in sourсe #XX -- [ Pg.211 ]




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