Primary Polymerization

Out of m monomer species you can make different polymers each of length N. Although they will only differ in the sequence of monomer rniits, i.e. in the primary structure, this difference might be very important. Thus, the munber of possible polymers grows exponentially with their length, = exp(ATlnm). 

there were too many sequences to try out. Far from it. By the way, what sort of chains are we talking about Over the last years, more 

we are not that worried about the particular chemistry of the polymers. What is more important is the very fact of the chain structure. It is just because all the monomers line up in a chain that we end up with a horrendous number of possibilities, m, which cannot all be tried out. 

The mixture of early evolutionary products on the Earth is usually called the primordial soup. In this soup, there were monomers which could join up with each other, given favorable conditions, and they formed some polymer chains. This is a well established fact, proved by laboratory experiments. Moreover, some of the polymers created had a slight ability to act as catalysts this has also been confirmed by experiments. However, what could have happened next is much less clear. 

One scenario discussed in the literature is the formation, by chance, of mutually catalyzing polymers. Manfred Eigen of Max Planck Institute in Gottingen (Germany) and his co-workers worked out a model, called hypercycle, which represents a sort of evolution on the level of polymers [25]. The model is dressed up in a beautiful mathematical clothes of differential equations, but its essence is simple. 

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The primary polymerization product ia these processes has a relatively wide molecular weight distribution, and a separate step is often used to narrow the polydispersity. Such a narrowkig step may consist of high vacuum stripping to remove volatile polymer chains, often followed by a solvent fractionation step (35,36), sometimes a solvent fractionation step alone (37,38), or a fractional precipitation from organic solvent (32). The molecular weight distribution can also be narrowed by depolymerization at elevated temperatures ia the presence of a depolymerization catalyst (217—220). 

Programs containing lignins as the primary polymeric dispersant are generally formulated to provide 30 to 50 ppm of active lignin product in the BW. 

Polymerization The process of producing higher-molecular-weight compounds by reacting two or more unsaturated molecules together. In the refinery, propylene and butylene are the primary polymerization feedstocks. 

The present observations could well be explained on the same basis since hexamethylcyclotrisiloxane polymerizes via both anionic and cationic mechanisms (5). (No evidence exists to date for free radical polymerizations.) The greater activity of H2O as an inhibitor, as compared with NH3, is explained on the basis of a more rapid ion transfer. Since this would be a hydrogen ion rather than a hydride ion, it further suggests an anion as the primary polymerization species in the present polymerization. The authors feel, however, that further work is required before definite conclusions can be drawn regarding the polymerization mechanism or mechanisms. 

There are two primary polymerization approaches step-reaction polymerization and chain-reaction polymerization.12... 

Investigation into the Composition of the Primary Polymerization Products of Propene and Butenes. 

Monomer Droplets. The monomer droplets serve primarily as reservoirs that supply monomer to the reaction sites in the polymer particles. These droplets can also contain a variety of other oil-soluble ingredients including dissolved polymer, chain transfer agents, and in unusual cases oil-soluble initiator. The monomer and other ingredients, if they have the requisite water solubility, are transported to the primary polymerization locus in the polymer particles. Reaction phenomena that can occur in the monomer droplets include the following ... 

Polymeric micelles, which were first introduced by Ringsdorf in 1984 [14], are an assembly of amphiphilic block copolymers in an aqueous environment. Primary polymeric micelles have a well-defined core-shell structure - a hydrophobic inner core and a hydrophilic shell. Micelles can incorporate water-insoluble drugs into the cores through chemical, physical, or electrostatic interactions [15], such as in micelles that are composed of a block copolymer of poly(ethylene glycol) and polyaspartate (Fig. 2) [16-18], A phase II study of a paclitaxel (PTX)-incorporated micelle, NK105, that is used in the treatment of stomach cancer, has begun [19]. 

Most polymers may be dispersed as a solution or an emulsion, thus acting as a base for synthetic varnishes. In addition to the primary polymeric resin (the binder) and the dispersing fluid (organic solvents or water), paint consists also of pigments, fillers, plasticizers, catalysts and stabilizers. Domestic... 

At the radical chain polymerization of oligomer containing n vinyl groups per molecule, the length of a primary polymeric chain will be equal to [121] ... 

An alternate and improved means to achieve enhanced coagulation in treating drinking water, a composition for removing turbidity, particles, and color from drinking water, includes (a) primary polymeric coagulant refers to a cationic polymer (a natural, cationic polymer as chitosan or a cationic starch) which enhances the... 

While the former was obtained directly by reaction of [Ybljfthf), ] with KlReCpj], the latter was synthesized via salt elimination from (Ybljfthf) ] and Na[RuCp(CO)2] followed by cracking of the isocarbonyl linkages in the primary polymeric product with 4-tert-butylpyridine (Scheme 3.3, top and middle) [13]. Using an iodo-bridged, NHC-stabilized dimer of neodymium and K[FeCp(CO)2], a complex with an unsupported Nd-Fe bond was obtained (Scheme 3.3, bottom) [14],... 

There are two primary polymerization approaches step-reaction polymerization and chain-reaction polymerization. In step-reaction (also referred to as condensation polymerization), reaction occurs between two polyfunctional monomers, often liberating a small molecule such as water. As the reaction proceeds, higher-molecular-weight species... 

Vamac D is used as the primary polymeric component in low smoke flooring. Vamac flooring also has sound deadening capabilities (Table 6.43). 

Since the polypeptide formed by the polymerization of an NCA with a simple amine is itself amine ended, sequential polymerizations can be conducted with different NCA monomers leading to AB diblock copolypeptides or, with a further cycle of operation using the original monomer, to ABA triblock copolymers. In the latter case, the outer A blocks may not be of equal lengths and, where such equality is required, a better procedure is to initiate the primary polymerization bidirectionally with a diamine according to the scheme of equation (24). " " ... 

Study of homopolymerization (of DAIP, for example) by DSO and SPR-spectroscopy methods has shown [81] that the process is separated into two stages quasi-linear polymerization and structuring. Monomer consumption proceeds with formation of primary polymeric chains, whereas structuring is characterized by formation of secondary polymeric chains by double bond. 

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