Copolymerisation constants

All the copolymerisation reactions are characterised by the copolymerisation constant rl and r2 defined as ... 

Based upon the values of the copolymerisation constants of these systems, formation probabilities of various unit sequences in the macromolecules of the copolymers were calculated using the Wall and Medvedev formulae. Based on these data, as well as the... 

Table 8.8 Copolymerisation constants and activity factors at copolymerisation of fluorine-oxygen containing methacrylates (MJ with MMA (M2) [73] ...

To estimate compositional inhomogeneity of synthesised copolymers, integral curves of the distribution by composition estimated by the Laury-Mayer method are calculated based on values of copolymerisation constants obtained, which confirmed that the compositional inhomogeneity decreased on approaching the azeotropic composition of the initial monomeric mixture [52, 65]. Based upon the previously mentioned data it is found that MMA-4FMA copolymers are the most homogeneous as defined by both structure of the macromolecules and type of units distribution in the chains and create compositionally homogeneous polymeric materials with the best optical characteristics [3]. 

Table 8.15 Value of copolymerisation constants fo and activity factors in reaction of their block radical co r MMA and 3FMA >olymerisation...

The study of ethylene and hexane-1 copolymerisation has been carried out with the catalytic system formed by the interaction of Mg(C2H5)Cl, THF, and TiCl4, in the presence of hydrogen. Two modifications have been synthesised with deposition on Si02 and without deposition. Catalysts have been revealed to exhibit a wide distribution of active centre activity, which was characterised by the copolymerisation constant r values varied from 5-7 to 2000 [71]. The narrowest distribution was... 

In a copolymerisation involving two monomers, A and B, reacting polymer chains can have either monomer A or monomer B at the growing end. As a result, there are four possible reactions Chain-end A (written A ) with monomer A or monomer B, and chain-end B ( B ) with A or with B. Each has a different rate constant, which can be designated and... 

The details of which type of complex (it- or n-) has what kinetic and other effects, e.g., on termination and transfer constants, copolymerisation ratios, tacticity, etc., need to be worked out on the basis of published results and well-aimed new experiments. 

Compositionally uniform copolymers of tributyltin methacrylate (TBTM) and methyl methacrylate (MMA) are produced in a free running batch process by virtue of the monomer reactivity ratios for this combination of monomers (r (TBTM) = 0.96, r (MMA) = 1.0 at 80°C). Compositional ly homogeneous terpolymers were synthesised by keeping constant the instantaneous ratio of the three monomers in the reactor through the addition of the more reactive monomer (or monomers) at an appropriate rate. This procedure has been used by Guyot et al 6 in the preparation of butadiene-acrylonitrile emulsion copolymers and by Johnson et al (7) in the solution copolymerisation of styrene with methyl acrylate. 

A polymer containing [Ru(bpy)3]2+—like centres bound has been prepared by copolymerisation of [Ru (bpy)2(MVbpy)]2+ and sodium styrenesulphonate (1 20 molar ratio) in the presence of3—cyclodextrin (O Connell 1983). This sample is quenched by PVS with a rate constant (1.0xl09dm3mol l) rather similar... 

The first example for Method 2 was reported by Nishide and co-workers, who polymerised a metal complex of 1-vinylimidazole with l-vinyl-2-pyrollidone and divinylbenzene [8]. The metal-vinylimidazole complex was copolymerised, cross-linked with l-vinyl-2-pyrollidone by y-ray irradiation and the template metal ion was removed by treating the polymer complex with an acid. These poly(vinyl-imidazole) (PVI) resins adsorbed metal ions more effectively than the PVI resin prepared without the template. The number of adsorption sites and the stability constant of the Ni(II) complex were larger for the PVI resin prepared with the Ni(II) template, as seen by the smaller dissociation rate constant of Ni(II) from the resin. 

Rosatzin et al. copolymerised V,W-dimethyl-V,V -bis(4-vinylphenyl)-3-oxapen-tanediamide (a metal ionophore), divinylbenzene and styrene in a chloroform solution in the presence of Ca(ll) or Mg(II) [10]. The Ca(II) ionophore resin is illustrated in Scheme 9.4. The metal ion added to the matrix mixture, was expected to act as a template for the ionophore during the polymerisation. The resulting polymers were analysed for their ability to extract ions from aqueous methanol. The polymers prepared against Ca(II) and Mg(II) were found to bind Ca(II) with 6- and 1.7-times lower dissociation constants, respectively, when... 

The above logic has been applied to the copolymerisation equations given in Table I. A detailed derivation of the copolymerisation model and a summary of the constants used in the model have been described elsewhere (17). 

Experimental System The copolymerisation of styrene with methyl acrylate in toluene using azo-bis-iso- butyronitrile (AIBN) was selected as the model experimental system because the overall rate of reaction is relatively fast, copolymer analysis is relatively simple using a variety of techniques and the appropriate kinetic and physical constants are available in the literature. This monomer combination also has suitable reactivity ratios (i = 0.76 and r4 =0.175 at 80 C),(18) making control action essential for many different values if compositionally homogeneous polymers are to be prepared at higher conversions in a semi-batch reactor. 

In the propoxylation of glycerol, the addition rate of PO to the hydroxyl groups of the starter is different when compared with the addition rate of PO to the formed secondary hydroxyl groups. It is observed that glycerol has two primary hydroxyl groups and one secondary hydroxyl group. In the studies of PO copolymerisation with EO, the ratio r between the reaction constant of PO with secondary hydroxyl (K22) and the reaction constant with primary hydroxyl (K21) is [56, 71] ... 

Table 4.6 Reaction constants for copolymerisation of EO with PO and EO with BO at various temperatures ...

In the case of PO (monomer 1) copolymerisation with THF (monomer 2) in the presence of hydroxyl groups, the reactivity constants of copolymerisation r and r are ... 

---