Polyacrylamide cryogels by photoinitiated free radical polymerization

Abstract

A novel method for the preparation of poly(acrylamide) cryogels by photoinitiated polymerization of monomeric precursors was described. A series of poly(acrylamide) cryogels were easily prepared by irradiating aqueous solutions containing acrylamide and N,N′‐methylene(bis)acrylamide as monomer and cross‐linker, respectively, in the presence of 1‐[4‐(2‐hydroxyethoxy)phenyl]‐2‐hydroxy‐2‐methyl‐1‐propane‐1‐one (Irgacure 2959) as water‐soluble photoinitiator with the help of freezing–thawing procedures. Photolysis was conducted at −13 °C isothermally through specially designed cryostat‐integrated Rayonet merry‐go‐round photoreactor. On comparing the described photochemical method with the conventional redox counter part, the polymerization is initiated, and gelation proceeds only on external stimulation by light. This way, concomitant hydrogel formation usually observed with the redox process as a result of premature polymerization during the cooling process was prevented. The obtained cryogels exhibited superfast swelling behavior. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

Hydrophilicity Tunable Hyperbranched Polymers by Visible Light Induced Self‐Condensing Vinyl Polymerization

“…Photoinduced approaches, commonly utilized for various polymerizations, possess several advantages consisting of low temperature conditions, requirement of little energy and minimized side reaction . Based on mentioned advantages, such light‐triggered systems have successfully been employed for the preparation of different macromolecular architectures such as block, graft copolymers, hydrogels, cryogels, and nanocomposites …”

Photo‐mediated metal free atom transfer radical polymerization of acrylamide in water

“…Polyacrylamide (PAM) is one of the most widely used water‐soluble polymers in the field of soil conditioner, wastewater treatment, the cosmetic, paper, biomedical applications, and textile industries, etc. In industry, PAM and its derivatives are obtained by the free radical polymerization . To a certain extent, the application of PAM is limited because of the large residue of acrylamide monomer in PAM.…”

Hyperbranced Polymers by Photoinduced Self‐Condensing Vinyl Polymerization Using Bisbenzodioxinone

“…Photoinitiated polymerizations have many advantages over the other polymerization processes including rapid polymerization rates at room temperature, availability of a wide range of photoinitiators, environmental issues, spatial and sequential control of the polymerization, and minimized side reactions . These advantages also lead to successful preparation of both block and graft copolymers, hydrogels, cryogels, as well as metal and clay nanocomposites by photoinitiated techniques.…”