Synthesis, characterization, and swelling studies of pH‐ and thermosensitive hydrogels for specialty applications

Abstract

In this article, we describe a novel pH-and temperature-sensitive and moderately salt tolerant hydrogels based on acrylic acid (AAc) and methacrylic acid (MAAc) by employing a novel research plan. AAc and MAAc have been converted to N-isopropylacrylamide (Ni-PAAm) and N-isopropyl methacrylamide (N-i-PMAAm), respectively, via amidation with isopropyl amine, followed by polymerization to respective polymers. These polymers were further converted into networks in the presence of AAc and MAAc and N,N-methylene bisacrylamide (N,NMBAAm). The networks thus formed consist of both amides and carboxylic acid groups. Characterization of these networks has been carried out by nitrogen analysis, FTIR, NMR, and scanning electron microscopy for the investigation of different structural aspects of the synthesized polymers. Swelling studies of these networks have been carried out as a function of time, temperature, pH, and in the presence of additives, sodium dodecyl sulfate, cetyl trimethyl ammonium bromide, and 5% NaCl solution.

Synthesis of acryloyl guar gum and its hydrogel materials for use in the slow release of l-DOPA and l-tyrosine

“…3.1). Such behavior of AGG-g-poly(AAc) and AGG-g-poly(MAAc) is explained by the formation of a transient network in the stronger acidic medium, and the result is shrinking and consequent poor swelling (Chauhan & Chauhan, 2008). The same is also true in the case of AGG-g-poly-(HEMA) where its primary hydroxyl group interacts to form interpolymeric associations.…”

“…In view of the above, and in continuation to our earlier work on the preparation of stimuli responsive biopolymers based hydrogels (Chauhan & Chauhan, 2008;Chauhan, Chauhan, Chauhan, Kumar, & Kumari, 2007;Chauhan, Guleria, & Sharma, 2005;Chauhan & Mahajan, 2002), in this article we report synthesis of acryloyl guar gum (AGG) and its hydrogel materials for use in the drug delivery applications. We have not come across any report on the derivatization of guar gum to its acryloyl form.…”

“…On the other hand, AGG-g-poly(AAc) and AGG-g-poly(MAAc) exhibited good salt tolerance as these retained high amount of water even after 120 min. In the pre-swollen hydrogels the polymer matrix is opened-up by the absorbed water, and when in contact with the saline solution, it looses the water due to ex-osmosis (Chauhan & Chauhan, 2008). This is more vividly expressed in the case of AGG-g-poly(HEMA) and AGG-g-poly(HPMA) which by their low hydrophilic nature cannot hold much water in the saline solution, hence rapid deswell was observed in these two cases as compared to the other two hydrogels.…”

“…FTIR spectrum was recorded on Nicollette 5700 in transmittance mode in KBr. Swelling studies were carried as a function of time (30-480 min), pH (2.0 and 7.4 pH), and in 0.9% NaCl solution at 37°C following an earlier reported method (Chauhan & Chauhan, 2008). Percent swelling (P s ) of the hydrogel materials was evaluated as follows: Loading and release of L-DOPA and L-tyrosine was carried at 37°C.…”

Glow discharge electrolysis plasma initiated preparation of temperature/pH dual sensitivity reed hemicellulose-based hydrogels

“…Intelligent hydrogels, which exhibit sensitive responses to environment, such as temperature, pH, salt, electric field, and chemical environment, are widely applied in sensors, drug release, tissue engineering and other fields (Gupta, Vermani, & Garg, 2002;Juntanon, Niamlana, Rujiravanit, & Sirivat, 2008;Wu et al, 2008;Hua, Chen, Li, & Zhao, 2008;Chauhan & Chauhan, 2008;Wang, Gao, & Wang, 2012). Temperature and pH sensitive hydrogels, the most important kind of intelligent hydrogels, have been paid special attention.…”