Functionalization of Microcrystalline Cellulose through Integrated Sodium Periodate and TEMPO/Ozone Oxidations

2024-09-12T12:36:53+07:00

Cellulose modification has been a primary focus in developing bio-based degradable functional materials. In this study, an integrated approach combining sodium periodate (NaIO₄) and TEMPO (2,2,6,6-tetramethylpiperidin-1-oxyl)-ozone oxidation process is employed to functionalize microcrystalline cellulose (MCC). The resulting materials in water-soluble and precipitate fractions were characterized to understand the influences of each oxidation method on the reaction mechanisms, structures, and physicochemical properties of the oxidized MCC samples. The results demonstrated that the combination of both methods resulted significantly in chemical structures, morphology, and surface reactivity of the samples. FTIR spectra showed an appearance of oxidized functional groups, i.e., carboxyl, ketone, and aldehydes, confirming a successful oxidation process. The use of ozone as a co-oxidant contributes positively to environmental aspects and process economics due to its availability and low cost. These findings illustrate the considerable potential of ozone utilization in improving cellulose properties for various applications. Consequently, the integrated approach offers an effective and sustainable solution for enhancing the quality and performance of cellulose, paving the way for further research and applications in the field of cellulose materials.

Keywords: Microcrystalline cellulose, TEMPO, Periodate, Ozone, Oxidation process

Network Dimension Theory and Its Application to Miniemulsion Vinyl/Divinyl Copolymerization

2024-09-21T16:34:55+07:00

Newly developed network dimension theory is used for rapid estimation of the root-mean-square radius of gyration of each polymer molecule formed during vinyl/divinyl copolymerization. The -value is used for describing the enhancement of intramolecular crosslinking or the cyclization reactions. The model is applied to the miniemulsion copolymerization, and both conventional free-radical polymerization and ideal living polymerization are considered. Some of important characteristics of network architecture formed in these two types of polymerization mechanisms that cannot be predicted based on the classical chemical kinetics can be reproduced by the model successfully. For example, such unique characteristics as the pendant double bonds are consumed from the start of polymerization in conventional free-radical polymerization but not so in living polymerization can be elucidated. The present kinetic model provides useful insights into the size- and structure-dependent network formation.

Keywords: Crosslinking, Emulsion polymerization, Gelation, Graph diameter, Radius of gyration

SIAM: Science and Innovation of Advanced Materials

Functionalization of Microcrystalline Cellulose through Integrated Sodium Periodate and TEMPO/Ozone Oxidations

Network Dimension Theory and Its Application to Miniemulsion Vinyl/Divinyl Copolymerization