Preparation and Swelling Properties of Temperature‐Sensitive Semi‐Interpenetrating Polymer Networks Composed of Poly[(N‐tert‐butylacrylamide)‐co‐acrylamide] and Hydroxypropyl Cellulose

Abstract

Summary: Temperature‐responsive hydrogels based on linear HPC and crosslinked P(NTBA‐co‐AAm) were prepared by the semi‐IPN technique. The structure of these semi‐IPN hydrogels was investigated by FT‐IR spectroscopy. An increase in normalized band ratios (A2980/A1665) was observed with increasing HPC content in the initial mixture. The swelling kinetics and water transport mechanism of these semi‐IPN hydrogels were examined and their temperature responsive behaviors were also investigated by measuring equilibrium swelling ratios and pulsatile swelling experiments. The results showed that these semi‐IPN hydrogels underwent a volume phase transition between 18 and 22 °C irrespective of the amounts of MBAAm and HPC. However, below the volume phase transition temperature, their equilibrium swelling ratios were affected by the amount of MBAAm and HPC. The pulsatile swelling experiments indicated that the lower the MBAAm and the higher HPC contents in semi‐IPN hydrogels the faster the response rate temperature change.Equilibrium swelling ratios of the semi‐IPN P(NTBA‐co‐AAm)/HPC hydrogels in water shown as a function of temperature.magnified imageEquilibrium swelling ratios of the semi‐IPN P(NTBA‐co‐AAm)/HPC hydrogels in water shown as a function of temperature.

Formulation and characterization of tramadol-loaded IPN microgels of alginate and gelatin: Optimization using response surface methodology

“…The swelling behaviour of MGs is linked to the diffusion process, which in turn depends on the nature of polymer network, cross-linking density and elasticity of the polymeric network (17). The negative influence of gelatin on the diffusion coefficient is clearly demonstrated by the response surface plots (Fig.…”

Enhanced Absorbent Products Incorporating Cellulose and Its Derivatives: A Review

“…In particular, to minimize the time and cost of drying, one would want any SAPs to be in a mostly non-swollen condition before the start of a conventional drying operation. As noted earlier in this article, various researchers have demonstrated thermally-sensitive hydrogels that incorporate a cellulosic component (Harsh and Gehrke 1991;Kuwabara and Kubota 1996;Çaykara et al 2006;Chang et al 2009b). Under laboratory conditions many such SAPs have been shown to release 80 to 90% of their water content upon heating to 40 o C (Kuwabara and Kubota 1996;Çaykara et al 2006;Ma et al 2007).…”

“…As noted earlier in this article, various researchers have demonstrated thermally-sensitive hydrogels that incorporate a cellulosic component (Harsh and Gehrke 1991;Kuwabara and Kubota 1996;Çaykara et al 2006;Chang et al 2009b). Under laboratory conditions many such SAPs have been shown to release 80 to 90% of their water content upon heating to 40 o C (Kuwabara and Kubota 1996;Çaykara et al 2006;Ma et al 2007). It would seem reasonable that such systems could be further developed, along with adjustments in the capabilities of washing machines, such that home laundering of "thermally smart" reusable superabsorbent products could become a practical reality.…”

“…It seems likely that some of the high levels of water uptake reported for SAPs based on interpenetrating networks (e.g. Çaykara et al 2006;Chang et al 2009b) may be due to one network interfering with the crosslinking of the other network during its preparation.…”

“…Some authors have called thermal changes in absorbency a "smart" feature, since they may allow specialized applications of a thermo-sensitive hydrogel (Pourjavadi et al 2007b;Yang et al 2011). Typical temperature-responsive hydrogels exhibit markedly decreased absorbency with increasing temperature (Harsh and Gehrke 1991;Kuwabara and Kubota 1996;Çaykara et al 2006;Chang et al 2009b). Decreases in absorbency as high as a factor of five (Kuwabara and Kubota 1996) or ten (Çaykara et al 2006) have been reported when comparing absorbency at about 20 o C to the correspondding value at about 40 o C. The strongest thermal effects are for SAPs incorporating relatively high proportions of poly(N-isopropylacrylamide); these generally exhibit a strong decrease in absorbency at temperatures near to physiological conditions (Kuwabara and Kubota 1996;Liu et al 2004;Chang et al 2009b;Yang et al 2011).…”