Monomers solvent soluble

In order to increase the organic solvent solubility of the polymers formed by reaction of 2,4,6-trichloroborazine with a disilazane, Paine et al. proposed the selective use of alkyl- substituted R-chloroborazines as monomers.32 These polymers are intended for materials applications, where the methyl substituent is used to ensure... 

Anionic polymerization of 1,4-DVB by n-BuLi leading to the microgels was also reported by Eschwey et al. [236,237]. In their experiments, n-BuLi was used at very high concentrations of 17 and 200 mol % of the monomer. Contrary to the results of Hiller and Funke [231], they observed a transition from microgel to macrogel with decreasing n-BuLi concentration. Similar results were also reported by Lutz and Rempp [238]. They used potassium naphthalene as the initiator of the 1,4-DVB polymerization and THF as the solvent. Soluble polymers could only be obtained above 33 mol % initiator, whereas below this value macrogels were obtained as by-products. 

The most important feature of the chromium compounds, as well as of the other derivatives of early transition 3difference between the derivatives of different oxidation states (T able 12.18). The alkoxides of chromium (II and HI) are in the majority the insoluble and non-volatile polymers. The most important exclusion from this rule appears to be the volatile chelate Cr(OCMe2CH2OMe)3 complex, and in the future, possibly, the number of the representatives of this family will increase. The derivatives of chromium (IV and VI) are monomers highly soluble in organic solvents. The lack of volatility for Cr(VI) compounds in contrast to those of Cr(IV) is caused apparently by the high electronegativity of the central atom, leading to thermal destruction and not to evaporation. 

This experiment is an example of a step-growth polymerization that takes place at the interface of two immiscible solutions. For this reaction, a diamine dissolved in water reacts with a diacid chloride that is dissolved in an organic solvent. Because neither of the monomers is soluble in the solvent containing the others reaction can occur only at die surface4 or interface between the two solutions. The product is a polyamide, either nylon-6,6 or nylon-6,10, depending upon the number of carbon atoms in the diacid chloride chosen. This activity works well either as a laboratory experiment or as a demonstration. 

For organic solvent solubility, an alternative approach to solubilising polyanilines and polypyrroles, without sacrificing high electrical conductivity, is the use of surfactant-like dopant anions. With polypyrrole this has recently been achieved via oxidation of the pyrrole monomer with ammonium persulfate in the presence of dodecylbenzene sulfonate [128,129]. Similarly, the conducting emeraldine salt form of PAn.HA can be readily solubilised in a range of organic solvents via the use of camphorsulfonic acid or dodecylbenzenesulfonic acid as the dopant, HA [130,131]. 

Results. Column extraction offers a new method of sample preparation and can be applied to liquid raw materials and solids that are solvent soluble. The column extraction method is promising and offers an efficient alternative for a range of materials. Excellent extractions of Cu, Fe, Co and Ni are obtained with the PL-Thiourea, while only Cu and Fe are extracted with the PL-Thiol column for this monomer (Table 6.9). 

Properties White crystals. Mp 114-116C (decomposes). Slightly soluble in water, cool 5% alkaline solution, and alcohols moderately soluble in oxygenated organic solvents and polyester monomers slightly soluble in naphtha, carbon tetrachloride, and chloroform insoluble in benzene. 

The minimum requirements for a dispersion polymerization are monomer, solvent/nonsolvent, initiator, and steric stabilizer. The monomer must be soluble in the reaction mixture and its polymer, insoluble. The monomers used in systems of commercial interest are methyl methacrylate, vinyl chloride, vinyli-dene chloride, vinyl esters, hydroxyl alkyl acrylates. A typical recipe for dispersion polymerization is shown in Table 9. 

The ability to incorporate different counterions into any conducting polymer backbone is largely dictated by the requirement for mutual monomer—counterion solubility. Whereas for polyanilines this is limited by the need for acid conditions to dissolve the monomer, for polythiophenes it is often limited by the need for an organic solvent to achieve monomer dissolution. 

Macroradicals can be prepared by free-radical-initiated solution polymerization of monomers in poor solvents. Monomers with solubility parameters similar to those of the macroradicals may form block copolymers in solvents that are poor solvents for both the macroradical and the block. The ability of a block macroradical to add an additional block is governed by the solubility parameter of the initial chain in the macroradical, and not by the solubility parameter of the end block. For the formation of macroradicals, it is essential that the solubility parameters of the monomer and polymer differ by at least 1.8 hildebrand units. For the formation of block copolymers, it is essential that the difference in solubility parameters of the monomer and macroradical be less than 3.2 hildebrand units. 

It was found, that a comparable reactivity and mobility of comonomers and good solubility of a trimerization catalyst in monomers (or monomer-solvent system) were desirable for the successful preparation of polycocyclotrimers. 

Solution Polymerization. Solution polymerization is over 45 years old, but only about 3% of the PVC produced in the United States is made this way. The solution process differs from the other processes already discussed in that a solvent is added to the polymerization system. The system may be heterogeneous, in which case the monomer is soluble but the polymer is insoluble. Examples are the use of hexane, butane, ethyl acetate, or cyclohexane as solvents. After addition of a peroxide initiator and heating to 40 C, the polymerization starts and polymer precipitates out of solution as formed. In homogeneous reactions, both monomer and polymer are soluble therein. Examples are the use of dibutyl phthalate and tetrahydrofuran as solvents. 

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