Incorporation into polymer

Radicals incorporated into polymer radicals formed by initiator... [Pg.353]

Miscellaneous Applications. Ben2otrifluoride derivatives have been incorporated into polymers for different appHcations. 2,4-Dichloroben2otrifluoride or 2,3,5,6-tetrafluoroben2otrifluoride [651-80-9] have been condensed with bisphenol A [80-05-7] to give ben2otrifluoride aryl ether semipermeable gas membranes (336,337). 3,5-Diaminoben2otrifluoride [368-53-6] and aromatic dianhydrides form polyimide resins for high temperature composites (qv) and adhesives (qv), as well as in the electronics industry (338,339). [Pg.333]

The fraction of trans segments, y, incorporated into polymers is given by the ratio (rate of formation of trans-segments)/(rate of formation of all segments), i.e. [Pg.128]

The electrochemical stripping of ions incorporated into polymer films can also be used in the sense of release of reagents into solution 261-264) jjjg electrochemically stimulated and controlled release of drags and neurotransmitters from... [Pg.76]

A variety of additives are available for incorporation into polymers to act as antioxidants. A selection of these additives is listed in Table 8.2 together with the names of the polymers for which they are most suited. [Pg.123]

As already shown, it is technically possible to incorporate additive functional groups within the structure of a polymer itself, thus dispensing with easily extractable small-molecular additives. However, the various attempts of incorporation of additive functionalities into the polymer chain, by copolymerisation or free radical initiated grafting, have not yet led to widespread practical use, mainly for economical reasons. Many macromolecular stabiliser-functionalised systems and reactive stabiliser-functionalised monomers have been described (cf. ref. [576]). Examples are bound-in chromophores, e.g. the benzotriazole moiety incorporated into polymers [577,578], but also copolymerisation with special monomers containing an inhibitor structural unit, leading to the incorporation of the antioxidant into the polymer chain. Copolymers of styrene and benzophenone-type UV stabilisers have been described [579]. Chemical combination of an antioxidant with the polymer leads to a high degree of resistance to (oil) extraction. [Pg.143]

Metal atoms can be incorporated into polymers using two approaches. For probing new reactions between metal atoms and polymers a small-scale spectroscopic approach, sometimes referred to as the Fluid Matrix Technique (11), is used. The coreactant polymer matrix, containing on the order of 0.5 fll of polymer, is preformed on an optical surface. In the case of viscous fluids such as 2 the material is painted on the substrate and held at temperatures ranging typically from 200 to 270 K. The temperature is chosen to maintain low volatility but retain mobility. Under high vacuum [10 6 torr]... [Pg.241]

By taking into account the latest results on the behaviour of systems far away from equilibrium, Kondepudi and Nelson (1985) were able to show by calculation that L-amino acids are slightly favoured. There is a very tiny stabilisation effect due to the weak interaction amplification mechanisms cause this effect to reach 98% of the probability that L-enantiomers of amino acids are favoured for incorporation into polymers. The amplification mechanisms are explained by the thermodynamics of irreversible systems. [Pg.250]

Many of the linear conjugated tricyclic systems have interesting fluorescence or other electrophysical properties. Bis-pyrazolepyridines such as compound 30 have been incorporated into polymers as fluorescent chromophores <1999JMC339>, and used in doped polymer matrices <1997JMC2323>. They are electroluminescent at 425 nm and photoluminescent at 427 and 430 nm in a poly(vinylcarbazole) matrix with a quantum efficiency of 0.8. [Pg.716]

We have shown a new concept for selective chemical sensing based on composite core/shell polymer/silica colloidal crystal films. The vapor response selectivity is provided via the multivariate spectral analysis of the fundamental diffraction peak from the colloidal crystal film. Of course, as with any other analytical device, care should be taken not to irreversibly poison this sensor. For example, a prolonged exposure to high concentrations of nonpolar vapors will likely to irreversibly destroy the composite colloidal crystal film. Nevertheless, sensor materials based on the colloidal crystal films promise to have an improved long-term stability over the sensor materials based on organic colorimetric reagents incorporated into polymer films due to the elimination of photobleaching effects. In the experiments... [Pg.92]

Sulfonated styrene-divylbenzene copolymers. See Styrene-divinylbenzene copolymers, sulfonated Sulfonate moeities, incorporation into polymers, 23 534, 535 Sulfonate surfactants, 24 146 Sulfonating reagents composition of, 23 520t indirect, 23 522-523t Sulfonation, 9 273-275, 313, 23 513-536, 12 181... [Pg.901]

Plotting Cl versus Co as suggested above (e.g., letting K equal 5, ci equal 0.2, and Ktf equal 10 ), it will be noted that when co is less than K or D> Co = Cl. At Co equals Aq, an abrupt transition occurs, and any further increases in Co leave ci unchanged at the value of (i.e., any protomer in excess of the critical concentration, Kd, becomes incorporated into polymer). For co less than Kd, the concentration of polymer will be zero. [Pg.184]

By step (a), a picture could be formed of the kinetics of the intracellular incorporation of 3H from [3H]arabinose into the major polysaccharides of the cell wall. Radioactivity was incorporated into polymer-bound arabinose and xylosyl-glucose units after lag periods of about 3.5 min and... [Pg.41]

The phthalocyanine moiety (LXa), where M represents a coordinated metal, has been incorporated into polymer structures. LXa is abbreviated by structure LXb. One reaction... [Pg.172]

This mixed product consists of small, platy particles with a relatively high surface area (15-20 m g ). The principal interest has to date been as a flame retardant Aller, principally for polypropylene. Both component phases decompose endothermically with the release of inert gas at relatively low temperatures. They are stable enough to allow incorporation into polymers such as polypropylene, but not polyamides. The performance of the two phases alone and in combination in polypropylene has been reported [91]. As expected from their thermal properties, hydromagnesite was the more effective flame retardant. The decomposition pathway of hydromagnesite has been shown to be considerably affected by pressure and this may affect its flame retardancy [71]. [Pg.96]

In addition to its role as a pigment, carbon black may be incorporated into polymers as a reinforcement for elastomers, as a UV stabiHser in polyolefins, or as an electrically conducting additive. In each case the physiochemical properties of the filler and its ultimate state of dispersion is critical in order to achieve... [Pg.178]

Ethylene-15% methacrylic acid copolymer Polyvinylcarbazole CdS and PbS incorporated into polymer films Size-quantized CdS particles incorporated into polymers... [Pg.135]

One of the obvious objectives of metal ion incorporation into polymers is to modify the essential bulk properties of these polymers with regard to miscellaneous end-uses. To this end however, structure-property correlations although useful, are difficult to achieve, particularly when high polymer networks are involved. This section will highlight how metal-ion incorporation can affect thermal stability, electrical and other useful properties of the polymer systems of which they are part... [Pg.111]

Phenanthroline is claimed to be an inhibitor of the polymerization of unsaturated nitriles.545 Certain phenyl substituted 4,7-phenanthrolines have been patented as ultraviolet absorbing compounds for incorporation into polymers.608,609... [Pg.69]

Another method by which carbazole has been incorporated into polymers is by acid-catalyzed condensation with formaldehyde. It was shown (79MI11103) that linear, soluble polymers (37) could be prepared when the substituent on the 9-position was propyl or larger. With methyl or ethyl substitution there is apparently little steric inhibition to condensation at the 1-position as well, and crosslinked polymers are the result. [Pg.276]

The oxolane (tetrahydrofuran) ring system can be incorporated into polymers either by polymerization of the suitably substituted heterocycle itself or by addition polymerization of a dihydrofuran derivative. A prime example of the former case is found in the utilization, as a component of adhesives and coatings for example, of the acrylate (38) and methacrylate (39) esters of tetrahydrofurfuryl alcohol. Although the bulk of the investigations concerning these monomers is recorded in the patent literature, a detailed study of the polymerization behavior of ester (39) has appeared (74MI11101) that indicates it is a fairly typical methacrylate monomer. [Pg.276]

The type 3 capsular polysaccharide199 (38) was found375,376 to be efficiently formed from UDP-Glc and UDP-GlcA. Under optimal conditions, >90% of the glycosyl groups of the glycosyl nucleotides was incorporated into polymer identified by immunochemical methods. [Pg.326]

Much work has been undertaken to modify electrode surfaces with films which are themselves conducting. The most promising approaches involve organic charge transfer and radical ion polymers. Coordination chemistry has, to date, played little part in this work (a good recent review is available),67 but one example relating to ferrocene chemistry can be quoted. In this example a well known electron acceptor, 7,7, 8,8 -tetracyanoquinodimethane (TCNQ 27), is modified and incorporated into polymer (28) in which the iron(II) of the ferrocene unit is the electron donor. The electrical conductivity of such a film will depend on partial electron transfer between ion and TCNQ centres as well as on the stacking of the polymer chains. The chemistry of other materials, based on coordination compounds, which have enhanced electrical conductivity is covered in Chapter 61. [Pg.24]

Table 14 gives data on the effect of acidification on the Soret band of a number of proteins. Accompanying the drop in the wavelength there is a decrease in intensity of the band. Directly comparable with this observation is the study of hemes incorporated into polymers by Weight-man (66). His results show that the Soret band moves well below 400 nm... [Pg.146]

Gramain and Frere [82] observed that the free radical polymerization of co-meth-acryloyl terminated PEO macromonomers in the aqueous phase deviates from the solution polymerization. Polymerizations initiated by KPS in water were much faster than those that proceeded in the solution. Low molecular weight polymers were formed in the aqueous systems (ca. up to 20 macromonomer units were incorporated into polymer molecules). [Pg.34]

Thiols are typically incorporated into polymers for gene delivery to take advantage of the reducing environment of the cytoplasm. Thiols can be mildly oxidized to produce disulfide (S-S) bonds for delivery vehicle crosslinking,... [Pg.154]

In addition to post-functionalizing polymers by bonding the macrocycle to the preformed polymer backbone, macrocycles can be incorporated into polymer matrices by direct polymerization of the macrocycle, either by a step-growth mechanism or a chain-growth mechanism. [46] Polymeric crown ether stationary phases were pioneered by Blasius et al. [34, 59-62] These resins were used to separate both cations (including protonated amines) with a common anion, and anions with a common cation in high... [Pg.354]

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