Association copolymers

Associative copolymers of acrylamide with N-alkylacrylamides, terpoly-mers of acrylamide, N-decylacrylamide, and sodium-2-acrylamido-2-methyl-propane sulfonate (NaAMPS), sodium acrylate (NaA), or sodium-3-acrylamido-3-methylbutanoate (NaAMB) have been shown to possess the required rheologic behavior to be suitable for enhanced oil-recovery processes [1184]. 

Varadaraj R, Branham KD, McCormick CL, Bock J (1994) Analysis of hydrophobi-cally associating copolymers utilizing spectroscopic probes and labels. In Dubin P, Bock J, Davis R, Schulz DN, Thies C (eds) Macromolecular complexes in chemistry and biology. Springer-Verlag, Berlin, p 15... 

Incorporation of Ti02 into polystyrene(s), styrene-acrylonitrile, acrylonitrile-butadiene-styrene, and other associated copolymers and alloys is normally by way of concentrates prepared on equipment similar to that used for polyethylene. This concentration step is usually necessary to achieve high-quality dis-persion so color properties are fully developed and physical properties are not compromised. 

The maximum per cent hypochromism and the associated copolymer composition appear to be functions of the solvent used (see Table II) however, no simple correlation with solvent thermodynamic power was detected. To the contrary, a linear correlation with the solvent dielectric constant was demonstrated. In fact, the copolymer composition corresponding to the maximum hypochromism at 269.5 nm is lineally dependent on the solvent dielectric constant (see Figure 3). The intercept corresponding to the value dielectric constant = 1 (which means that there are no interactions of solvents) gives the copolymer composition really responsible for the maximum hypochromism, namely about 30 mole % methyl methacrylate. Furthermore, the maximum per cent hypochromism is a linear function of the solvent dielectric constant (see Figure 3) extrapolation gives a value of about 14%. 

Hydrophobically Associating Copolymers. Hydrophobically modified cellulose derivatives (28) and N-alkylacrylamido copolymers (24, 25, 27) were among the first nonionic associative thickeners reported in the patent literature. The concentration of hydrophobic units allowed for dissolution in aqueous solution is usually less than 1-2 mol %. Like conventional polymers, apparent viscosity is proportional to molecular weight and concentration. However, with associative copolymers, a very dramatic increase in apparent viscosity occurs at a critical concentration, C, which clearly is related to a phenomenon other than simple entanglement. Viscosity dependence on hydrophobe concentration, size, and distribution suggests mi-croheterogeneous phase formation. Surfactants enhance viscosity behavior in some instances (24), yet clearly reduce viscosity in others (i). 

Terpolymer solution behavior is dependent on compositional microstructure, polymer concentration, ionic strength, pH, temperature, and shear history. The viscosities of these low charge density terpolymers would be expected to be insensitive to changes in ionic strength below the critical overlap concentration, C above C intermolecular attractive forces might be expected to cause enhanced viscosities similar to those of hydrophobically associating copolymers. 

KLE Kleiner, M., Tumakaka, F., Sadowski, G., Latz, H., and Buback, M., Phase equilibria in poly disperse and associating copolymer solutions Poly(ethene-co-(meth)acrylic acid) monomer mixtures, Fluid Phase Equil, 241, 113, 2006. 

F. 28 Arrhenius plots of (a) measured dye diffusion coefficient ( )) and (b) steady-shear viscosity for poly(butyl acrylate)s with UPy side groups. The cartoons emphasize that molecular diffusion is determined by the equilibrium association constant, whereas viscous relaxation is determined by the rate of bond dissociation. RevCTsibly associating copolymers (RAC) contain UPy side groups and control copolymtas (CCP) do not. Adapted from [149] with permission of The Royal Society of Chemistry... 

NMR experiments are widely used to investigate the self-aggregation process of amphiphilic polymers. Most of these substances have been designed as drug carriers and present a multi-block architecture. Poly(ethylene glycol) blocks are often found in self-associating copolymers. 

Three different approaches were used for preparing the hydrophobically associating copolymers shown in Figure 1. 

Formation of hydrophobically associated copolymers of polyacrylic acid with long-chain amines by use of a carbodiimide [129]. 

Becker F, Buback M, Latz H, Sadowski G, Tumakaka F (2004) Cloud-point curves of ethylene-(meth)acrylate copolymers in fluid ethene up to high pressures and temperature -experiment study and PC-SAFT modeling. Fluid Phase Equilib 215 263-282 Kleiner M, Tumakaka F, Sadowski G, Latz H, Buback M (2006) Phase equilibria in polydisperse and associating copolymer solutions poly(ethylene-co-(meth)acrylic acid)-monomer mixture. Fluid Phase Equilib 241 113-123... 

The aliphatic polyesters implemented by ROP were the earliest and have been the most extensively studied polymers for their inherent biodegradability. Their uniqueness lies in their immense diversity. Most of them have already been industrialized and found applications in medicine, food, and agriculture. In Table 1, the structure of the industrialized monomers and the corresponding homopolymers are listed. PLA, PGA, and their associated copolymers, as well as PCL are the most investigated. The synthesis (related with industrial aspects), properties, applications, and perspective developments of these polyesters will be discussed hereafter. 

Analysis of Hydrophobically Associating Copolymers Utilizing Spectroscopic Probes and Labels... 

Varadaraj et al. [29] have demonstrated that the Ej 30) probe can be used as an extrinsic probe to study the hydrophobic microdomains formed due to polymer association in the hydrophobically associating copolymer system acrylamide-alkylacrylamide. The probe was solubilized in the aqueous polymer solution and absorption spectra recorded. Results are given in Table 2.1. 

The solubility characteristics of hydrophobically associating copolymers of p(alkyl acrylamide-co-acrylamide), RAM, have been studied by a number of... 

Hill, A., Candau, F. and Selb, J. (1991) Aqueous solution properties of hydrophobicaUy associating copolymers. Prog. Colloid Polym. Sci., 84, 61-65. 

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