Abstract
Superabsorbent polymers (SAPs) are crosslinked hydrophilic polymers that are capable of absorbing large amounts of water. Commercial SAPs are mostly produced with acrylic acid that cannot be easily biodegraded. Therefore, in this study, polysaccharide-based SAPs using carboxymethyl cellulose as a major component were prepared. Starch aldehydes and citric acid were selected due to their environment-friendly, non-toxic, and biodegradable properties compared to conventional crosslinking agents. Starch aldehydes were prepared by periodate oxidation, which forms aldehyde groups by taking the places of C–OH groups at C-2 and C-3. Furthermore, starch aldehydes were analyzed through the change in FT-IR spectra, the aldehyde quantitation, and the morphology in FE-SEM images. In the crosslinking of polysaccharide-based SAPs, the acetal bridges from starch aldehydes led to a large amount of water entering the network structure of the SAPs. However, the ester bridges from citric acid interfered with the water penetration. In addition, the swelling behavior of the SAPs was analyzed by the Fickian diffusion model and the Schott’s pseudo second order kinetics model. The relationship between swelling behavior and morphology of the SAPs was analyzed by FE-SEM images. In conclusion, polysaccharide-based SAPs were well prepared and the highest equilibrium swelling ratio was 87.0 g/g.
Highlights
Superabsorbent polymers (SAPs) are crosslinked hydrophilic polymers that are capable of absorbing large amounts of water [1]
Methanol used for washing as well as hydroxylamine hydrochloride, methyl orange, and sodium hydroxide used for degree of substitution (DS) calculation were purchased from Samchun Pure Chemical, Co., Ltd.(Pyeongtaek, Korea) Citric acid was purchased from Showa Chemical Industry Co., Ltd. (Tokyo, Japan) while sulfuric acid was used as the catalyst and purchased from Junsei Chemical Co., Ltd., Tokyo, Japan
In the spectra of native starch, strong and broad peaks were detected at 3600–3200 cm−1, which are due to hydrogen bonded hydroxyl groups [35]
Summary
Superabsorbent polymers (SAPs) are crosslinked hydrophilic polymers that are capable of absorbing large amounts of water [1]. It has been reported that the presence of hydrophilic groups, the flexibility of high polymer chain, and the availability of large free volumes among polymeric chains enhance the swelling capacity of SAPs [2]. Because of their excellent characteristics, SAPs are Polymers 2018, 10, 605; doi:10.3390/polym10060605 www.mdpi.com/journal/polymers. Polysaccharides are major sources of bio-based SAPs. There have been many studies using starch [4], carboxymethyl cellulose (CMC) [6], alginate [7], chitosan [8], and carrageenan [9]. Starch and its derivatives have been utilized in many industrial applications such as food, medicine, and cosmetic fields [12]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
