Synthesis, rheological behavior and swelling properties of copolymer hydrogels based on poly(N-isopropylacrylamide) with hydrophilic monomers

Abstract

ABSTRACT. In this study, hydrogels of poly(N-isopropylacrylamide-co-acrylamide) and poly(Nisopropylacrylamide-co-acrylic acid) having a thermoresponsive character were prepared by aqueous free-radical co-polymerization using the ammonium persulfate/N,N,N', N'-tetramethylethylenediamine (APS/TEMED) redoxpair initiator system in the presence of N,N'-methylenebisacrylamide (MBAAm) crosslinker. (NIPAAm-co-AAm) and (NIPAAm-co-AAc) hydrogels with different thermoresponsive properties were obtained by fixing the initial NIPAAm/AAm mole ratio and and (NIPAAm-co-AAc) mole ratio to 80/20 and changing the crosslinker concentration. The copolymers were characterized with infrared spectroscopy (IR) and differential scanning calorimetry (DSC) techniques. The swelling response of the copolymers networks as a function of time, temperature and swelling environment has been observed to be dependent on both structural aspects of the polymers and swelling environment. The swelling has been observed to be decrease with increase in MBAAm in the copolypolymers networks. Rheological behavior was studies in oscillatory module. All copolymers have a viscoelastic behaviour. We note that the elastic modulus G' increases with increasing hydrophilic monomers.

Release behavior of a polyanion‐crosslinked chitosan‐poly(N‐isopropylacrylamide) gel thermoresponsive material

“…An endothermic peak and an exothermic peak were observed at about 100 °C and 300 °C, respectively. The endothermic peak at 100 °C corresponds to the glass‐transition temperature of PNIPAAm . The exothermic peak at 300 °C corresponds to the decomposition of chitosan .…”

“…The endothermic peak at 100 8C corresponds to the glass-transition temperature of PNIPAAm. 21 The exothermic peak at 300 8C corresponds to the decomposition of chitosan. 22 Therefore the hydrogel was composed of chitosan and PNIPAAm.…”

PENYEDIAAN DAN PENCIRIAN HIDROGEL BERASASKAN KANJI/AKRILAMIDA DARIPADA UBI Stemona curtisii

“…Hidrogel dengan kandungan kanji yang banyak akan meningkatkan sifat kebolehbasahan, sifat hidrofilik dan darjah pembengkakan [14]. Namun, darjah pembengkakan hidrogel bukan sahaja bergantung pada keadaan hidrogel dan media pembengkakan tetapi ia juga amat bergantung pada ketumpatan taut-silang hidrogel dan kepekatan bahan campur adun seperti kepekatan agen taut-silang dan kepekatan monomer [15].…”

“…Ini menghadkan ruang di dalam jaringan hidrogel untuk mengembang [13]. Ruang yang terhadap ini secara langsung telah menghalang monomer AAm ataupun kanji untuk mengikat molekul air melalui ikatan hidrogen [15].…”

Synthesis and Investigation of Double Stimuli-Responsive Behavior ofN-Isopropylacrylamide and Maleic Acid Copolymer in Solutions

“…The lower critical solution temperature (LCST) of the thermo-responsive polymers is strongly dependent on the chemical structure; thus it can be modulated by variation in the hydrophilic or hydrophobic groups in the polymer chain [3]. In particular, the phase transition temperature of poly(N-isopropylacrylamide) (poly(NIPAAm)) can be shifted closer to the human body temperature by copolymerization with hydrophilic comonomers [7]. Poly(NIPAAm) is one of the typical well studied thermoresponsive polymers with potential and already implemented applications in the medical field.…”