Simultaneous characterization of poly(acrylic acid) and polysaccharide polymers and copolymers

Abstract

Copolymer products that result from grafting acrylic acid and other hydrophilic monomers onto polysaccharides have recently gained significant interest in research and industry. Originating from renewable sources, these biodegradable, low toxicity, and polar copolymer products exhibit potential to replace polymers from fossil sources in several applications and industries. The methods usually employed to characterize these copolymers are, however, quite limited, especially for the measurement of bulk properties. With more sophisticated applications, for example, in pharmaceutics requiring a more detailed analysis of the chemical structure, we describe a new approach for this kind of complex polymers. Our approach utilizes chromatography in combination with several detection methods to separate and characterize reaction products of the copolymerization of acrylic acid and chemically hydrolyzed starch.These samples consisted of a mixture of homopolymer poly (acrylic acid), homopolymer hydrolyzed starch, and -in a lower amount -the formed copolymers. Several chromatographic methods exist that are capable of characterizing either poly (acrylic acid) or hydrolyzed starch. In contrast, our approach offers simultaneous characterization of both polymers. The combination of LC and UV/RI offered insight into the composition and copolymer content of the samples. Size exclusion chromatography experiments revealed the molar mass distribution of homopolymers and copolymers. FTIR investigations confirmed the formation of copolymers while ESI-MS gave more details on the end groups of hydrolyzed starches and poly (acrylic acids). Evidence of copolymer structures was obtained through NMR measurements. Finally, two-dimensional chromatography led to the separation of the copolymers from both homopolymers as well as the additional separation of sodium clusters. The methods described in this work are a powerful toolset to characterize copolymerization products of hydrolyzed starch and poly(acrylic acid). Together, our approach successfully correlates the physicochemical properties of such complex mixtures with their actual composition.

Chitosan-Grafted Polyacrylic Acid-Doped Copper Oxide Nanoflakes Used as a Potential Dye Degrader and Antibacterial Agent: In Silico Molecular Docking Analysis

“…65 CuO surface plasmon vibration excitation generated an absorption peak at 294 nm. 66 PAA strong absorption below 235 nm 67 and the CS absorption peak at 208 nm 68 shifted to 340 nm in the grafted structure. The Tauc plot was constructed to estimate the optical band gap (Eg) through straight-line part extrapolation toward the x axis presented in Figure 3b.…”

Mapping of the Hydrophobic Composition of Lignosulfonates

“…Since changes in the inherent amphiphilic character of lignosulfonates have an immediate impact on their performance as surface-active agents, having a clear picture of the hydrophobic composition of lignosulfonates is critically important for the efficient and effective use of these valuable natural products. A comprehensive characterization of complex polymers like lignosulfonates requires multidimensional approaches to unravel the actual structural composition, which is typically accomplished by coupling of liquid chromatography (LC) methods or hyphenation with specific detection systems. − For lignosulfonates, determination of the MMD has been routinely implemented by size-exclusion chromatography (SEC), while the FTD is still limited to average values obtained by spectroscopic or wet chemical methods. ,, So far, more detailed information on the FTD has only been gathered through preparative sample fractionation using solvents or ultrafiltration and subsequent characterization of the fractions. − LC methods that aim to resolve analytically the FTD of lignosulfonates or lignins in general have only recently been pioneered, with hydrophobic interaction chromatography (HIC) being among the most promising approaches. − In HIC, the adsorption of solutes to a weakly hydrophobic stationary phase is favored by a high salt concentration in an aqueous mobile phase. Afterward, the elution of solutes is facilitated by a decrease in the salt concentration and/or the addition of modifiers (e.g., alcohols, detergents, and chaotropic salts).…”