Polymer insoluble high

Oince cellulose is insoluble high polymers under physiological condi- tions, cellulase which is destined to attack it has been expected to be an extracellular enzyme. In fact, most of cellulolytic microorganisms secrete some cellulase components into the culture medium, and almost all work on the cellulase have been performed using these extracellular components. In the cultures of cellulolytic bacteria, cellulases are not only found in their culture filtrates, but also are generally obtainable from the cells by treatment with autolytic agents—e.g., toluene (9, 19, 30). These facts indicate that at least certain components are existent within the bacterial cells and that their physiological function may be distinct from that of the extracellular components. 

Poly (vinyl alcohol) (PVAL), Manufactured by saponification of poly(vinyl acetate). As a special water-soluble and organic-insoluble high-polymer, it is used as a viscosity regulating agent, as a thickener and/or protecting colloid in dispersions and adhesives. A starting material for the production of poly(vinyl acetals). 

Polymerization. In the absence of inhibitors, acrolein polymerizes readily in the presence of anionic, cationic, or free-radical agents. The resulting polymer is an insoluble, highly cross-linked soHd with no known commercial use. 

AppHcations of soHd-state nmr include measuring degrees of crystallinity, estimates of domain sizes and compatibiHty in mixed systems from relaxation time studies in the rotating frame, preferred orientation in Hquid crystalline domains, as weU as the opportunity to characterize samples for which suitable solvents are not available. This method is a primary tool in the study of high polymers, zeoHtes (see Molecular sieves), and other insoluble materials. 

Another limitation is related to the fact that synthetic poly(amino acids) have rather unfavorable material properties. For instance, most synthetic poly (amino acids) derived from a single amino acid are insoluble, high-melting materials that cannot be processed into shaped objects by conventional fabrication techniques. The often undesirable tendency to absorb a significant amount of water when exposed to an aqueous environment is another common property of many poly (amino acids) (7). Finally, high molecular weight poly-(amino acids) are best prepared via N-carboxyanhydrides which are expensive to make. Hence poly(amino acids) are comparatively costly polymers, even if they are derived from inexpensive amino acids (8). 

The much larger insoluble polymer peak at high conversions may include insoluble graft polymer. The insoluble polymer peak tended to exhibit bimodal character at high conversion levels. 

Macromolecular Substitution Route. The current surge in poly-phosphazene research Is mainly a result of the development in the mid 1960 s (2-4) of a substitutive route to the synthesis of organo phosphazene high polymers. Before that time, only a sporadic interest in the subject existed because the known polymers, cross linked poly(dihalophosphazenes), (1,5) were insoluble and hydrolytically unstable. 

In 1988, Terry and coworkers attempted to homopolymerize ethylene, 1-octene, and 1-decene in supercritical C02 [87], The purpose of their work was to increase the viscosity of supercritical C02 for enhanced oil recovery applications. They utilized the free radical initiators benzoyl peroxide and fert-butyl-peroctoate and conducted polymerization for 24-48 h at 100-130 bar and 71 °C. In these experiments, the resulting polymers were not well studied, but solubility studies on the products confirmed that they were relatively insoluble in the continuous phase and thus were not effective as viscosity enhancing agents. In addition, a-olefins are known not to yield high polymer using free radical methods due to extensive chain transfer to monomer. 

Under free radical conditions, we found that the bulk polymerization of 4-allyloxystyrene gave an insoluble crosslinked polymer with AIBN. Similar results were previously reported for the polymerization with benzoyl peroxide (8). The cationic polymerization of /7-alkoxystyrene monomers have been shown to proceed at rates that are comparable to vinyl ethers (12,13). As expected from these studies, we found that alkenyloxystyrene monomers also have a high degree of cationic reac-... 

Photodimerization of cinnamic acids and its derivatives generally proceeds with high efficiency in the crystal (176), but very inefficiently in fluid phases (177). This low efficiency in the latter phases is apparently due to the rapid deactivation of excited monomers in such phases. However, in systems in which pairs of molecules are constrained so that potentially reactive double bonds are close to one another, the reaction may proceed in reasonable yield even in fluid and disordered states. The major practical application has been for production of photoresists, that is, insoluble photoformed polymers used for image-transfer systems (printed circuits, lithography, etc.) (178). Another application, of more interest here, is the use that has been made of mono- and dicinnamates for asymmetric synthesis (179), in studies of molecular association (180), and in the mapping of the geometry of complex molecules in fluid phases (181). In all of these it is tacitly assumed that there is quasi-topochemical control in other words, that the stereochemistry of the cyclobutane dimer is related to the prereaction geometry of the monomers in the same way as for the solid-state processes. 

It was observed that in some systems even oligomers are not able to complex but polymers with high molecular weight give insoluble, stable polymer-polymer complexes. The number of units in polymer chain sufficient for stable absorption is called critical length. Below the critical length, the growing chain can exist in solution, above the criti-... 

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