Xylan-Derived Light Conversion Nanocomposite Film

A new type of sustainable light conversion nanocomposite film was fabricated by using carboxymethyl xylan as matrix and xylan-derived carbon dots (CDs) as both light conversion regents and nano reinforcements. The results demonstrate that CDs can not only significantly enhance the mechanical strength of the nanocomposite film because of chemical reaction between CDs and carboxymethyl xylan, but also impart the film with excellent optical properties. With 1.92 wt% CDs, the tensile strength and elastic modulus of the film are increased by 114.3% and 90.7%, respectively. Moreover, the film has typical excitation and emission spectra, enabling the efficient absorption of UV and the conversion of UV to blue light. This xylan-derived light conversion nanocomposite film is expected to be used in agricultural planting and food packaging.

Fast-responsive temperature-sensitive hydrogels

Temperature fast-responsive and magnetic poly(N-isopropylacrylamide-co-acrylamide) (CMX-MNP-PNIPAm/Fe3O4) hydrogels were developed using carboxymethyl xylan (CMX) as a pore-forming agent and a NaCl solution as the reaction medium, followed by fabricating Fe3O4 nanoparticles in situ within the hydrogel matrix. It was found that NaCl played a role in the phase separation and was used as the electrolyte to shield CMX molecular chains. The obtained hydrogels exhibited a fast, temperature-responsive behavior, and the water retention was less than 15% for 1 min under 60 °C. The prepared hydrogels showed enhanced mechanical properties and magnetic properties due to the presence of Fe3O4 particles. The lower critical solution temperature of the hydrogels was in the range of 35 to 39 °C, which was acquired through adjusting the amount of hydrophilic monomer (AM). The magnetic and thermosensitive hydrogel had the attractive photothermal conversion ability and could be heated to 40 °C within 2 min, and to 69 °C within 7 min under near infrared irradiation.

Xylan-Based Hydrogels as a Potential Carrier for Drug Delivery: Effect of Pore-Forming Agents

Pore-forming agents have a significant influence on the pore structure of hydrogels. In this study, a porogenic technique was employed to investigate the preparation of macroporous hydrogels which were synthesized by radical copolymerization of carboxymethyl xylan with acrylamide and N-isopropylacrylamide under the function of a cross-linking agent. Six kinds of pore-forming agents were used: polyvinylpyrrolidone K30, polyethylene glycol 2000, carbamide, NaCl, CaCO3, and NaHCO3. The application of these hydrogels is also discussed. The results show that pore-forming agents had an important impact on the pore structure of the hydrogels and consequently affected properties of the hydrogels such as swelling ratio and mechanical strength, while little effect was noted on the thermal property of the hydrogels. 5-Fluorouracil was used as a model drug to study the drug release of the as-prepared hydrogels, and it was found that the drug release was substantially improved after using the NaHCO3 pore-forming agent: a cumulative release rate of up to 71.05% was achieved.