Synthesis and Characterization of Novel Poly(N-vinylcaprolactam-co-itaconic Acid) Gels and Analysis of pH and Temperature Sensitivity

Abstract

Poly(N-vinylcaprolactam-co-itaconic acid), P(VC-co-IA), gels were synthesized in ethanol by using the free radical cross-linking polymerization method at 60 °C for 24 h in the presence of azobis(isobutyronitrile) (AIBN) and allyl methacrylate (AMA) as the initiator and the cross-linking agent, respectively. In order to determine the effect of the synthesis medium on the percentage of gelation (PG) and equilibrium swelling value (ESV), an ethanol/distilled water mixture (80:20, v/v) was also used as the synthesis medium for poly(N-vinylcaprolactam) (PVC) and P(VC-co-IA) gels. The swelling behaviors of the gels were investigated in distilled water at various temperatures and in different pH buffer solutions. Structural, morphologic, and thermal characterization studies of the gels were carried out using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA), respectively. The lowest PG and highest ESV were obtained for the gel including 5 mol % IA, which was the gel synthesized in the ethanol/distilled water mixture. PVC synthesized in ethanol/water mixture had the highest percentage of gelation. All the gels displayed pH- and temperature-sensitive swelling behavior. The swelling kinetics of the copolymer gels synthesized in ethanol was investigated at pH 10.0, and it was determined that gels containing 5 and 10 mol % of IA indicated non-Fickian and case II swelling behavior, respectively.

Silicone Rubber Modified with Methacrylic Acid to Host Antiseptic Drugs

“…TGA analyses were carried out in the temperature range of 25–800 °C under inert nitrogen atmosphere. SR‐g‐MAA copolymer showed three steps of weight loss: the first step that occurred in the 200–280 °C range corresponds to the anhydrization of PMAA; the second one from 370 to 470 °C can be attributed to the scission of the main chain of PMAA, while the third one starting at 470 °C is due to thermal decomposition of SR.…”

Grafting of N‐vinyl caprolactam and methacrylic acid onto silicone rubber films for drug‐eluting products

“…The maximum weight loss (52%) occurred in the second stage. The thermal degradation of the SR‐ g ‐(VCL/MAA) 68% graft was shown by the two weight losses occurring in the 200–300°C region (due to the decarboxylation of PMAA) and 350–450°C region (due to the scission of the main chain of PMAA and PVCL) …”

Amylose‐Coated Biohybrid Microgels by Phosphorylase‐Catalyzed Grafting‐From Polymerization

“…[1][2][3] Special attention has been paid to microgels based on N-vinylcaprolactam (VCL) during the last years, since these exhibit outstanding properties like a high biocompatibility and temperatureresponsive behavior. [4][5][6] PVCL microgels show a volume phase transition at a temperature of 32 °C, [7,8] being swollen at temperatures below while losing water and thus collapsing at temperatures above. Due to the unique properties of PVCL microgels, numerous applications in the biomedical field were developed in the last years, for example, the use of PVCL-based microgels for drug release [6,9,10] or as contrast agent in tumor magnetic resonance (MR) imaging after gadolinium loading.…”