Terpolymers solution behavior

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. 

TIE Tiera, M.J., Santos, G.R. dos, Oliveira Tiera, V.A. de, Vieira, N.A.B., Frolini, E., Silva, R.C. da, and Loh, W., Aqueous solution behavior of thermosensitive (N-isopropylaciylamide-acrylic acid-ethyl methacrylate) terpolymers, Coll. Polym. Sci., 283, 662, 2005. 

In the concept of water soluble ABC block copolymers one has also to mention a huge amount of work that has been presented on the synthesis and solution behavior of copolymers with two hydrophilic blocks and one hydrophobic. However, the presence of a permanently hydrophobic block in this type of block polymers makes difficult their categorization as DHBCs. The synthesis of ABC triblock terpolymers with at least two hydrophilic blocks has been realized via a number of polymerization methodologies, like GTP and cationic polymerization, and has been studied in detail [42,43,44,45,46,47,48,49]. In most of the cases, the terpolymers were based on suitably functionalized methacrylate monomers and have been produced by the sequential monomer addition method. 

Effects of Shear Rate and Temperature. In nearly all instances, the polyampholytes showed only slight pseudoplastic or Newtonian behavior in deionized water and salt solutions in the dilute regime. In semidilute solutions near C, some shear thinning was observed by using Contraves rheometry however, the behavior was not pronounced. Only the imbalanced terpolymer systems, which are in essence polyelectrolytes, exhibited pseu-... 

Some time ago, we investigated the behavior PEO-containing PE terpolymer PS-PVP-PEO in aqueous solutions [88, 89], The micellization of this copolymer is strongly pH-dependent because PVP is protonized and therefore soluble in acidic solutions at pH lower than 4.8, but is deprotonized and therefore water-insoluble at higher pH. The PS-PVP-PEO micelle is a three-layer nanoparticle in which the PVP blocks form a middle layer between the rigid PS core and the PEO shell. The PVP layer is either collapsed at high pH, so that PS-PVP-PEO micelles resemble onion micelles formed in mixtures of PS-PVP and PVP-PEO diblock copolymers, or it is partially protonized, swollen, and flexible in acid aqueous media, so that the PVP layer becomes a soluble inner shell between the core and the outer PEO shell. 

In an extension of the above studies, terpolymers of 3, 4, and 5 (series II) (Scheme 5) were synthesized (57). Compositional analysis for this series of terpolymers is listed in Table 2. Weight-average molecular weights for this series range from 3.0 x 10 to 7.9 x 10 g mol It was initially postulated that these polymers would exhibit polyzwitterionic or polyelectrolyte behavior depending upon the pH. However, at low pH values, hydrogen bonding between the carboxylic acid and amide moieties limits solubility even in the presence of salts. Therefore, all solution studies were conducted at pH = 8. Under these conditions,... 

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