Preparation of pH‐responsive crosslinked materials from natural rubber and poly(4‐vinylpyridine)

Abstract

Stimuli‐responsive elastomers are smart materials for sensing applications. Natural rubber (NR) is a renewable elastomer with excellent elasticity and fatigue resistance. In this work, a straightforward method for the preparation of pH‐responsive crosslinked materials from NR and poly(4‐vinylpyridine) (P4VP) via free radical crosslinking reaction using benzoyl peroxide (BPO) as an initiator is described. The effects of P4VP and BPO concentrations, reaction time and reaction temperature on immobilization percentage were investigated. It was found that the immobilization percentage reached 90% when using a P4VP concentration of 150 phr and a BPO concentration of 10 phr for 24 h at 90 °C. The pH responsiveness of the crosslinked materials was studied via water swelling, water contact angle and dye release measurements. Unlike unmodified rubber, the P4VP‐crosslinked NR was found to be pH‐responsive in acidic solution. Indigo carmine adsorption studies showed the Langmuir isotherm suggesting monolayer coverage of dye on the rubber surface. The dye could also be released upon increasing the pH of solution above 4. Based on these results, the introduction of pH responsiveness to NR will lead to novel responsive rubber‐based materials that can be used in biomedical and sensing applications. © 2016 Society of Chemical Industry

Novel hydrogels based on a high‐molar‐mass water‐soluble dimethacrylate monomer

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“…Polymers that respond to pH typically contain ionizable groups that can accept or donate protons in response to the www.soci.org SV Asmussen, ML Gomez, CI Vallo environmental pH. [33][34][35][36][37] In this study, hydrogels containing pendant amino groups were prepared from mixtures of EBisEMA and DMAEMA (Scheme 1) in various EBisEMA-to-DMAEMA molar ratios (Table 3). Figure 8 shows the C C conversion versus irradiation time in EBisEMA-DMAEMA mixtures.…”

Smart Adsorbents for Aquatic Environmental Remediation

“…[153] A pH-responsive P4VP-NR adsorbent was prepared by free radical crosslinking of poly (4-vinylpyridine) (P4VP) and natural rubber (NRb), in the presence of benzoyl peroxide for indigo carmine (IC) dye adsorption and release. [154] A highly swollen P4VP-NRb surface was observed at pH < 4. In this pH range, pyridine, which is a weak base, converted to positively charged pyridinium salt, consequently generating electrostatic repulsion, which resulted in swelling of P4VP-NRb.…”

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