Polymerization outcome

The polymerization outcome depended on the monomer structure as well as on the enzyme origin. For instance, using HRP and p-n-alkylphenols, the... 

The success of thrombus lysis depends mainly on how large the thrombus is and whether any blood flow stiU remains. The outcome is better the larger the surface of the entire thrombus exposed to the thrombolytic agent. As the clot ages, the polymerization of fibria cross-linking and other blood materials iacreases and it becomes more resistant to lysis. Therefore, the eadier the thrombolysis therapy starts, the higher the frequency of clot dissolution. Thrombolytic agents available are Hsted ia Table 7 (261—276). 

Although equation 9 is written as a total oxidation of sugar, this outcome is never realized. There are many iatermediate oxidation products possible. Also, the actual form of chromium produced is not as simple as that shown because of hydrolysis, polymerization, and anion penetration. Other reduciag agents are chosen to enhance the performance of the product. 

Studies on the Bischler-Napieralski cyclization of A -acetyltryptamine in the presence of indole have led to the isolation of numerous products, among which the indolocarbazole 186 could be found in 3.5% yield. This outcome was rationalized as a result of the intermediacy of a spiroindolenine species formed under these conditions [89H(28)175]. During detailed studies on the polymerization of indole, formation of a low yield of the related indolo[3,2-h]carbazole 187 was discovered in the product mixture originating from the treatment of indole with p-toluenesulfonic acid at elevated temperature [88JCS(P1)2387]. In an investigation of the condensation of p-benzoquinone with 4-substituted anilines, an indolo[3,2-h]carbazole derivative has been reported to be formed in 2% yield (80JOC1493). 

Room temperature ionic liquids arc currently receiving considerable attention as environmentally friendly alternatives to conventional organic solvents in a variety of contexts.144 The ionic liquids have this reputation because of their high stability, inertness and, most importantly, extremely low vapor pressures. Because they are ionic and non-conducting they also possess other unique properties that can influence the yield and outcome of organic transformations. Polymerization in ionic liquids has been reviewed by Kubisa.145 Commonly used ionic liquids are tetra-alkylammonium, tetra-alkylphosphonium, 3-alkyl-l-methylimidazolium (16) or alkyl pyridinium salts (17). Counter-ions are typically PF6 and BF4 though many others are known. 

The outcome of the polymerization depends strongly on the particular monomer. Polymerizations of S, MMA, MA, VAc and some derivatives have been reported. Studies on model compounds indicate that the primary or secondary dithiocarbamatc end groups arc much less susceptible to photodissociation than benzyl or tertiary derivatives. 

Lewis acids (dicthylaluminum chloride, ethyl aluminum scsquichloridc) have been used in conjunction with ATRP to provide greater alternating tendency in S-MMA copolytnerization.519 However, poor control was obtained because of interaction between the catalyst (CuCI/dNbpy) and the Lewis acid. Better results were obtained by RAFT polymerization/10 Copper catalysts, in particular Cu(lI)Br/PMDETA, have been shown to coordinate monomer but this has negligible influence on the outcome of copolymerization/6 ... 

The development of living radical polymerization has provided the capability for the polymer chemist to synthesize a wide range of novel and well-defined structures. The transformation of this capability into commercial outcomes and novel products has only just commenced. 

Specialty formulas designed for use in specific clinical situations generally are much more expensive than standard polymeric formulas. Strong clinical trial data supporting use of these specialty formulas in niche populations typically are unconvincing in terms of patient outcomes. 

One of the most important outcomes of these efforts was impact-resistant polystyrene, which was obtained by modifying the brittle material with rubber. The first products were blends of polystyrene and synthetic rubbers recourse was soon made, however, to a principle that Ostromislensky (29) had suggested as early as 1927 styrene monomer was polymerized in the presence of rubber dissolved in it. 

Moreover, no NMR spectral changes were detected as a consequence of treating dehydropolymerizates from [1- C], [2- C] and [3- C]coniferyl alcohol, respectively, or a dehydrogenative copolymer of /7-[/ing-4 -i C]coumaryl alcohol and coniferyl alcohol, at pH 3.0 with racellular P, chrysosporium culture fluid, or purifled lignin peroxidase, in the presence of H2O2 nor was the outcome affected by prior methylation of the substrates (52). Thus the result originally encountered with the purified spruce wood extract (13) is not representative of polymeric lignin-like preparations at all. 

These results do not depend on the absolute values of aa and ab, or ba and bb. but on their ratio, and this means that the outcome of the copolymerization cannot be predicted on the basis of the kinetic parameters of the homopolymerization of A and B alone. This also means that the copolymer product can have a composition of A and B units drastically different from the composition of the starting monomer mixture. For example, starting from a 50 50 mixture of A and B, it may happen that the resulting chains contain only a very little percentage of A. This is so, even when A has a great tendency to polymerize on its own. 

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