Acrylic acid Block copolymers

Zhang L, Eisenberg A (1995) Multiple morphologies of crew-cut aggregates of polystyrene-6-poly(acrylic acid) block copolymers. Science 1268 1728-1731... 

A similar result can be concluded from the hydrophilicity of hydrophilic-hydrophobic copolymers. For example, it is well- known that at least 10 % hydrophilic segments is needed to disperse a statistical hydrophilic-hydrophobic copolymer in water. Whereas, in our work with vinyl acetate-neutralized acrylic acid block copolymers, stable dispersion in water was achieved even at 4 wt % acrylic acid content (Caneba and Dar, 2005). Finally, a comparative study of permeabilities has been made between block and random copolymers for sorption and diffusion of cyclohexane in styrene-butadiene copolymers (Caneba et al., 1983-1984). Since the permeability is proportional to the product of the diffusivity and solubility, numerical results for 10 wt % S contents indicate an increase in permeability for the block copolymer membrane compared to the random copolymer membrane. 

Tian, Y, Bromberg, L., Lin, S. N., Alan Hatton,T. and Tam, K. C. (2007). Complexation and release of doxorubicin from its complexes with pluronic P85-b-poly(acrylic acid) block copolymers. Journal of Controlled Release, 121,137-145. 

Block copolymers are often the choice for a wide variety of supramolecular assembhes, in which the fundamental driving force involves the mutual immiscibihly of the blocks and/or the immiscibility of one of the blocks in the bulk solvent. For example, poly(styrene-co-acrylic acid) block copolymers exhibit several interesting amphiphihc assembhes [181]. These self-assembled stmctures are the result of the incompahbihty between the hydrophobic polystyrene block and the hydrophihc poly(acryhc acid) block. The consequences of incorporating carboxyhc acid and benzyl moiehes, the key hydrophihc and hydrophobic funchonahhes in poly(acryhc acid) and polystyrene respechvely, within the same monomer of a homopolymer are interesting from an intramolecular phase separahon perspechve [182]. 

L. Zhang and A. Eisenberg, Morphogenic effect of added ions on crew-cut aggregates of polystyrene-b-poly(acrylic acid) block copolymers in solutions, Macromolecules, vol. 29, no. 27, pp. 8805-8815, 1996. 

Hydrolysis of the poly(r-BMA) blocks is achieved by dissolving the triblock copolymer (1 g) in dioxane (100 ml) at room temperature. Cone, hydrochloric acid (1.5 ml) is added, and the resulting mixture is heated (100 °C) and stirred for 18 h. After cooling to room temperature the solution is concentrated down to approx. 10 ml which are poured into cold (0 °C) diethylether (100 ml).The precipitate is filtered off, washed with methanol and dried in vacuo to constant weight.The result is an acrylic acid-b-styrene-b-acrylic acid triblock copolymer. 

Acrylic acid/acryiamide copolymer. See Acryiates/acrylamide copolymer Acrylic acid/acryiamide poiymer. See Acryiic acid/acrylamide copoiymer Acrylic acid/acrylonitrogens copolymer CAS 61788-40-7 136505-00-5 136505-01-6 Synonyms 2-Propenenitrile, homopolymer, hydrolyzed, block, reaction prods, with N,N-dimethyl-1,3-propanediamine... 

Colombani O, Ruppel M, Schubert F, Zettl H, Pergushov DV, Muller AHE (2007) Synthesis of poly(n-butyl acrylate)-block-poly(acrylic acid) diblock copolymers by ATRP and their micellization in water. Macromolecules 40(12) 4338-4350... 

The mesogen structures may be formed not only by covalent bonds, but also by non-covalent interactions, such as hydrogen bonds, ionic interactions, and metal coordination [71]. A recent example [72] of this concept comprised the self-assembly of complex salts into stable hierarchical aggregates with a dense core and a diffuse shell. These materials were made from diblock copolymers poly(acrylic acid)-block-poly(acrylamide) and the cationic surfactant dodecyltrimethylammonium. Due to non-covalent interactions the surfactant/polymer aggregates exhibited a liquid crystalline structure of cubic symmetry. 

Similar structures can also be prepared using ATRP chemistry and in this case the initiating group is simply a chloromethyl or bromomethyl species at a focal point [204], Linear poly (acrylate) and poly (acrylic acid) blocks [205,206] are then connected to the dendrimer at its core. They were prepared by the copper-catalyzed living radical polymerizations of acrylates with dendrimer-type macroinitiators having a benzyl bromide at the focal point. After hydrolysis, amphiphilic block copolymers with a linear PAA hydrophilic block and a dendritic poly (benzyl ether) as hydrophobic block were obtained [205,206]. 

The synthesis of cylindrical polymer brushes with amphiphilic poly(acrylic acid)-block-poly(n-butyl acrylate) (PAA-b-PnBA) diblock copolymer side chains is shown in Fig. 13.14. The procedure includes several steps (i) synthesis of a well-defined macroinitiator, PBIEM, by esterification of poly(2-hydroxyethyl methacrylate) (PHEMA), which was synthesized via ATRP of 2-hydroxyethyl methacrylate (HEMA) or anionic polymerization of silyl-protected HEMA (ii) ATRP of t-butyl acrylate (tB A) initiated by the pendant a-bromoester groups of PBIEM, yielding cylindrical brushes with PtBA homopolymer side chains (iii) sequential ATRP of n-butyl acrylate (nBA) forming the cylindrical bmshes with diblock copolymer [poly(t-butyl acrylate)-block-poly(n-butyl acrylate) (PtBA-b-PnBA)] side chains and (iv) hydrolysis of the PtBA block to produce the hydrophilic poly(acrylic acid) (PAA) block forming the core of an amphiphilic core-shell cylinder brash [106]. By using this technique, other well-defined core-shell cylindrical polymer brashes with polystyrene (PS), PS-b-PAA or PAA-b-PS, as side chains have been successfully synthesized. 

A number of methods such as ultrasonics (137), radiation (138), and chemical techniques (139—141), including the use of polymer radicals, polymer ions, and organometaUic initiators, have been used to prepare acrylonitrile block copolymers (142). Block comonomers include styrene, methyl acrylate, methyl methacrylate, vinyl chloride, vinyl acetate, 4-vinylpyridine, acryUc acid, and -butyl isocyanate. 

In nonrigid ionomers, such as elastomers in which the Tg is situated below ambient temperature, even greater changes can be produced in tensile properties by increase of ion content. As one example, it has been found that in K-salts of a block copolymer, based on butyl acrylate and sulfonated polystyrene, both the tensile strength and the toughness show a dramatic increase as the ion content is raised to about 6 mol% [10]. Also, in Zn-salts of a butyl acrylate/acrylic acid polymer, the tensile strength as a function of the acrylic acid content was observed to rise from a low value of about 3 MPa for the acid copolymer to a maximum value of about 15 MPa for the ionomer having acrylic acid content of 5 wt% [II]. Other examples of the influence of ion content on mechanical properties of ionomers are cited in a recent review article [7],... 

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