Water-swellable rubber blend from epoxidized natural rubber and superabsorbent polymer composite

Abstract

Epoxidized natural rubber (ENR) and a superabsorbent polymer composite (SAPC) along with other minor components were mechanically blended in an internal mixer (Brabender Plasticorder) at 40°C and 60 r/min rotor speed with 80% fill factor. The SAPC was synthesized by grafting polyacrylamide onto hydroxyethyl cellulose backbones and adding bentonite clay. The first water-swelling behavior was investigated with alternative epoxidation levels of the ENR. Water-swellable rubber (WSR) performed well in terms of water absorbency, and weight loss was achieved with 50 mole% epoxidation level, so this ENR was chosen for the rubber matrix from which WSR was prepared with various contents of SAPC (0, 5, 10, 15, and 20 phr). The results indicated that SAPC loading positively affected water absorbency, which was resulted by increasing weight loss and loss of mechanical properties, such as tensile strength and elongation at break. However, the modulus increased with SAPC content. WSR formulated from ENR-50, SAPC, and other ingredients resulting in good water-swelling behaviors and modulus, while the tensile strength and elongation at break had opposition. SAPC was an important factor to control the overall WSR properties.

Preparation and characterization of hydrophilic and water‐swellable elastomeric nanocomposites

“…This reducing trend in strength upon swelling may be due to breaking of total network density (both physical and chemical networks) as water leached into bulk matrices, similar to those earlier observed by Adair et al [ 51 ] The order of the effect of water swelling on the decreasing tensile strength of the samples (SR1‐SR3) is; SR1 > SR3 > SR2, this followed the decreasing order of network density ( N ); SR1 > SR3 > SR2. With reference to Table 3, SR1 is about 2402 and 1282.4% higher in crosslinking density than SR2 and SR3 respectively, hence SR1 is higher even in extreme swelling state.…”

“…However, as clearly seen, the swellability of the current composition was retained at levels which still qualified them as suitable WSE. Comparatively, the effect of PEO in the current composition (C) degree of swelling (%) versus time and (D) absorption rate of samples yielded higher water swelling performance than those reported by Adair et al [51] whose composition (ENR-SAP) swollen in water for 30 days recorded a swelling degree of $35%.…”

“…to the matrix into the water. A sharp drop in water swelling property was observed by Adair et al [51] for the case of ENR-SAP composite and this were linked to reduction of crosslinking density. However, as clearly seen, the swellability of the current composition was retained at levels which still qualified them as suitable WSE.…”

Preparation of water swellable rubber from epoxidized natural rubber and sodium acrylate by in‐situ polymerization: Effect of vulcanization system, epoxide, and dicumyl peroxide, and sodium acrylate content

“…Similar behavior was also observed in the preparation of WSR from ENR and superabsorbent polymer composite. 38 When comparing ENR 25 and ENR 50, it was observed that the tensile strength of WSR from ENR 50 was higher than that of WSR from ENR 25. However, there was no significant difference in elongation at break and hardness between the two.…”

Hotspots, Frontiers, and Emerging Trends of Superabsorbent Polymer Research: A Comprehensive Review

“…Owing to excellent water absorbency, retention, and hydrogel properties, SAPs have obtained extensive applications ( Wu et al, 2000 ; Zohuriaan-Mehr and Kabiri, 2008 ; Zohuriaan-Mehr et al, 2010 ; Ahmed, 2015 ), especially in fields such as hygienic products ( Shahi et al, 2017a ; Shahi et al, 2017b ), agriculture ( Zhang et al, 2014a ; Zhang et al, 2014b ; Guilherme et al, 2015 ; Fang et al, 2018 ), pharmacy and medicine ( Mastropietro et al, 2012 ), tissue engineering ( Stamatialis et al, 2008 ), wound dressings ( Wiegand et al, 2011 ; Capanema et al, 2018 ), soil-less cultivation ( Takeuchi, 2019 ), biosensors ( Qasemi and Ghaemy, 2020 ), smart materials ( Vosseler et al, 2012 ), electrical applications ( Boruah et al, 2015 ), construction ( Vieira et al, 2014 ), fibers and textiles ( Majchrzycka et al, 2017 ), separation/water treatment ( Zhou et al, 2016 ), sludge/coal dewatering ( Zhang et al, 2017 ), and water-absorbing rubber ( Adair et al, 2020 ). So far, the hygienic applications, particularly disposable diapers as described by Wu et al, 2000 , have occupied the largest market share of SAP products and the agricultural applications the second largest.…”