Effect of poly(n-isopropyl acrylamide-co-itaconic acid) on the chemical polymerization of pyrrole with (NH4)2[Ce(NO3)6]

Macromolecular Symposia

2006

Copolymers and terpolymers of N‐t‐butylacrylamide (TBA) with 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS) and N‐hydroxy methyl acrylamide (NHMAAM) were prepared by solution polymerization in a 1:1 (v/v) mixture of methanol and water at 50 °C keeping the TBA content in the feed constant at 60% based on mole ratio. The contents of AMPS or NHMAAM used for the preparation of TBA‐AMPS and TBA‐NHMAAM copolymers were 40 mole %. Molar percentages of AMPS and NHMAAM monomers in the feed for the preparation of TBA‐AMPS‐NHMAAM terpolymers were varied as 10:30, 20:20, and 30:10, respectively. The effects of temperature, AMPS and crosslinker contents, and the drying of swollen gels on the swelling behavior of ionic and non‐ionic TBA gels were investigated in distilled water between 10–50 °C and in buffer solutions having various pHs (1.9, 3.1, 5.6, 7.1, and 9.8) with constant ionic strength of 0.08 M at 20 °C using both the dry and the swollen forms of gels. The chemical structures and microscopic morphologies of the polymers were investigated by FTIR and SEM, respectively.

Swelling Behavior of N‐t‐butylacrylamide Copolymer and Terpolymers

Kaçmaz

Macromolecular Symposia

2006

A novel poly(N‐isopropylacrylamide‐co‐N‐hydroxymethyl acrylamide) gel: preparation in the absence/presence of a pore‐forming agent and characterization

Polymers for Advanced Techs

Öz²

2008

Poly(N‐isopropylacrylamide) (PNIPAM) homopolymer gel and copolymer gels of N‐isopropylacrylamide (NIPAM) and N‐hydroxymethyl acrylamide (NHMAAM) were prepared in the absence/presence of a pore‐forming agents, poly(ethylene glycol) (PEG) (PEG 400 or PEG 2000) using N,N′‐methylenebisacrylamide (NMBA) as a crosslinker in aqueous solution at 4°C. The chemical structures and microscopic morphologies of PNIPAM and P(NIPAM‐co‐NHMAAM) copolymer gels were investigated by FT‐IR and SEM (scanning electron microscopy), respectively. The effects of initial monomer concentration (0.5 and 1 M), the contents of crosslinker (0.25 and 1%) and comonomer (1–3 mol%), the absence/presence of pore‐forming agent in the feed, and the molecular weight of pore‐forming agent on the compressive elastic moduli and equilibrium swelling values (ESVs) of both polymers were investigated. While the use of a pore‐forming agent during the polymer synthesis favored the formation of porous gels and increased the swelling values, it led to decrease in the compressive elastic moduli of PNIPAM and P(NIPAM‐co‐NHMAAM) gels. The swelling values of gels, which were prepared at high monomer (1 M) and crosslinker (1%) contents, were not dependent on the comonomer NHMAAM incorporation to PNIPAM, the use of pore‐forming agents, and the use of former and latter parameters together. The twice increase in initial monomer concentration at low NMBA (0.25%) content highly enhanced the elastic moduli of PNIPAM. One mol% NHMAAM incorporation into PNIPAM especially at low monomer (0.5 M) and crosslinker (0.25%) contents made the highest increase (4.7 times) in the elastic moduli of gel, and further increase in the NHMAAM content of gel decreased the moduli of gels at all crosslinker and monomer concentrations. It was concluded that the increase in the elastic moduli of copolymer gels with 1 mol% NHMAAM, which were prepared at low crosslinker and monomer concentrations, can be attributed to the increase in crosslinking through the condensation reaction between N‐methylol groups or N‐methylol and NH groups in NHMAAM and NIPAM. Copyright © 2008 John Wiley & Sons, Ltd.

Synthesis and swelling behavior of poly(2‐dimethylaminoethyl methacrylate‐co‐N‐hydroxymethyl acrylamide) hydrogels

Polymers for Advanced Techs

Çavuş

2006

Crosslinked poly(2‐(N,N‐dimethylamino)ethyl methacrylate‐co‐N‐hydroxymethyl acrylamide) poly(DMAEMA‐co‐NHMAAM) copolymers were synthesized using ammonium persulfate (APS)/N,N,N′,N′‐tetramethyl ethylenediamine (TEMED) as initiator/accelerator system in the presence of tetraethyleneglycol diacrylate (TEGDA) as crosslinker in water at 60°C. The effects of comonomer composition in the feed, pH of the swelling medium, and the temperature on the equilibrium swelling (ES) values of hydrogels were investigated. While the initial total monomer concentration was kept constant at 0.5 or 1 mol/l, the contents of APS and TEGDA in the feed were 1 mol% of the total monomers. ES values of DMAEMA‐NHMAAM gels increased with the increase in DMAEMA content in the feed. Although DMAEMA‐NHMAAM hydrogels containing up to 30 mol% were transparent in appearance, the presence of 40% DMAEMA in the copolymer worsened its transparency. ES values of the copolymer gels with high DMAEMA contents increased with both temperature and the pH of swelling medium. Copyright © 2006 John Wiley & Sons, Ltd.