Polymerization methods dichloride

Details of this experiment may be found in Ref. 1. The interfacial polymerization method to prepare polyamides involves the reaction of a diacid dichloride with a diamine between two immiscible liquids as the reaction zone (with or without stirring). The method is useful where the reactants are sensitive to high temperature and where the polymer degrades before the melt point is reached (as in melt polymerization techniques). 

A new acyclic diene metathesis polymerization method has been developed using 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene)benzylidene mthenium(II) dichloride as catalyst. This reaction catalyst was used for preparing oligomers and polymers containing amino acids or polypeptides. 

Condensation of dicarboxylic acids and both diaryl- or dialkyllead dichlorides generated lead-containing polymers, 101.233>234>235 The IF polymerization method was used and higher yields resulted using the bis-carboxylate salts. The lead centers in these polymers can exist as tetrahedral or octahedral geometries. The octahedral lead centers result from further coordination of two carbonyl oxygens to the lead atom. IR studies demonstrated both lead structures exist within the polymers. 

In emulsion polycondensation, the polymer formation reaction occurs in the bulk of one of the liquid phases. This method is employed for irreversible, exothermic polycondensations, accompanied by the liberation of a side product. Highly reactive monomers (e.g., dichlorides or dicarboxylic acids, diamines, etc.) are most suitable for emulsion polycondensation. To date, the number of step-growth polymers that are prepared using emulsion or mini-emulsion polymerization methods is small, and the technological aspects of this technique... 

Polyamines can also be made by reaction of ethylene dichloride with amines (18). Products of this type are sometimes formed as by-products in the manufacture of amines. A third type of polyamine is polyethyleneimine [9002-98-6] which can be made by several routes the most frequently used method is the polymeriza tion of azitidine [151 -56 ] (18,26). The process can be adjusted to vary the amount of branching (see Imines, cyclic). Polyamines are considerably lower in molecular weight compared to acrylamide polymers, and therefore their solution viscosities are much lower. They are sold commercially as viscous solutions containing 1—20% polymer, and also any by-product salts from the polymerization reaction. The charge on polyamines depends on the pH of the medium. They can be quaternized to make their charge independent of pH (18). 

Zirconocene dichloride 121 derived from (l-phenylethyl)cyclopentadienyl ligand is formed as a mixture of diastereomers from which the racemic form can be isolated by fractional crystallization. This complex was studied by X-ray diffraction methods and revealed a virtually chiral C2-symmetrical conformation in which the chiral ring-substituents are arranged in a synclinal position relative to the five-membered ring. It was proposed that this conformation is preserved in solution. Using 121 as catalyst the influence of double stereodifferentiation during isospecific polymerization of propylene (Eq. 32) was demonstrated for the first time [142],... 

PA-6,10 is synthesized from 1,6-hexamethylenediamine and sebacic acid, and PA-6,12 from 1,6-hexamethylenediamine and dodecanedioic acid. The melt synthesis from their salts is very similar to PA-6,6 (see Example 1). These diacids are less susceptible to thermal degradation.55 PA-6,10 can also be synthesized by interfacial methods at room temperature starting with the very reactive sebacyl dichloride.4 35 A demonstration experiment for interfacial polycondensation without stirring can be carried out on PA-6,10. In this nice classroom experiment, a polymer rope can be pulled from the polymerization interface.34... 

Since the determination of absolute rate constants is one of the most urgent problems in cationic polymerization, and the styrene-perchloric acid system seemed to be so clean and simple, Gandini and Plesch set out first to check Pepper and Reilly s results by determining spectroscopically the concentration of carbonium ions during polymerization, and they intended then to extend the method to other monomers. However, their findings were not as expected. A comparison of spectroscopic and conductivity measurements with rate measurements in an adiabatic calorimeter showed [4] that in methylene dichloride solution ... 

Molecular recognition, in Rh Cp complexes, 7, 155 Molecular weight, in alkene living polymerizations, 11, 715 Moller-Plesset calculations, as perturbation method, 1, 646 Molten salts, and ionic liquids, 1, 848 Molybdacarboranes, synthesis, 3, 216 Molybdenocene dichloride, bioorganometallic chemistry,... 

In only a few polymerization processes are metallocene catalysts used in a soluble form. Supported metallocene catalysts are preferred for the production of polyethylene or isotactic polypropylene on an industrial scale, especially in the slurry and gas-phase processes. To use them in existing technological processes (drop-in technology) as replacements for the conventional Ziegler-Natta catalysts, the metallocenes have to be anchored to an insoluble powder support, including silica, alumina, and magnesium dichloride (208-217). Various methods of anchoring catalysts to supports are possible (Fig. 25) ... 

Polymerisation. Emulsified droplets containing a monomer can react with a second monomer soluble in the continuous phase to form a membrane at the interface (i.e. diamine reacting with a acid dichloride). This is called interfacial polymerization. Many derivative methods can be set-up from this method, using pre-polymers in place of monomers, inversing the continuous and dispersed phases, developing a radical reaction. Covering all possible methods is not possible here. 

To investigate the copolymerization of trioxane with dioxolane and to determine r1 by the excess method, a molar ratio of trioxane to dioxolane of 100 1.8 was used. All polymerizations were run in methylene dichloride at 30°C. with SnCl as initiator. To reduce the influence of formaldehyde production at the beginning of copolymerization, dioxolane was added to the solution of trioxane and initiator only at the end of the induction period—i.e., at the appearance of the first insoluble polyoxy-methylene. After various reaction times polymerizations were terminated by adding tributylamine. Monomer conversions were determined by gas chromatography, the liquid phase being injected directly. When conversions were small, isolation and analysis of the copolymer yielded more accurate results. 

We will choose the example of elastane films for food wrapping— ClingFilm . These can be made from poly(vinylidene dichloride) (this is poly(l,l-dichloroethene)) into which a small amount of vinyl chloride is co-polymerized. The method is radical polymerization and the initiator usually a peroxide in aqueous suspension. 

In both cases the [I2 ] exponent was larger for polymerizations in the solvent of lower dielectric constant where the counter-ion, (deliberately omitted in the kinetic schemes), was, therefore, envisaged as tri-iodide ion, I3, corresponding to n = 2. In ethylene dichloride n = 1 and the gegenion was assumed to be unassociated, i.e. I . Visible spectrophotometry was used to measure [X], (=[I2]free " [I2M]) and, from a plot of [I2]total/[X] versus [M][X] /(1 + K[M])", the ratio was obtained. Data for K were obtained independently by ultraviolet spectrophotometry using well characterized methods [66, 67]. Thus having determined fej/fet, substitution of the experimental data, Rp, [M] and [I2] TOTAL) the final rate expression enabled values of fep to be calculated. Iodine is also conveniently estimated by iodometric titration... 

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