Variable temperature solid-state NMR spectral and relaxation analyses of the impregnation of polyethylene glycol (PEG) into coniferous wood

ACS Biomater. Sci. Eng.

Jiang

Sun

et al. 2022

Tetracyclines are well-known antibiotics and widely used against a variety of bacterial infections. Their monitoring and detection have been an important issue. To this end, a vast number of methods have been developed; fluorescence sensing is one of the most reported. However, most of the reported sensors are made from transition metals with sophisticated multiprocesses; polymers are hardly seen for this purpose, particularly biocompatible ones. Herein, an aqueous solution of poly(ethylene glycol) (PEG), well known for being biocompatible, is shown to emit under excitation of 280 nm, while the solutions of selected tetracyclines, namely, doxycycline (DOX) and tetracycline (TC), are non-emissive under the same conditions. In the binary solutions of PEG-DOX or PEG-TC, PEG emission is sharply quenched with high sensitivity and selectivity. PEG was then used as a sensor for DOX and TC detections in water with high performance compared to reported studies. The same tests were also done by DOX spiking in milk and tap water, demonstrating that DOX was practically fully recovered. The quenching mechanism was ascribed to the interaction between the O atoms of PEG in clusters and specific heteroatom groups on tetracycline molecules through hydrogen bonding, elucidated from FTIR and NMR analyses. Therefore, this work provides a novel, fully green, easy to operate, low cost, and reliable protocol for tetracycline monitoring and detection and opens new potential application for PEG.

Section: Resultsmentioning

confidence: 99%

Full Green Detection of Antibiotic Tetracyclines Using Fluorescent Poly(ethylene glycol) as the Sensor and the Mechanism Study

ACS Biomater. Sci. Eng.

Jiang

Sun

et al. 2022

“…Figure 5 shows that the intensity of the peaks at 83.78 and 88.77 ppm is relatively weak, which is also a manifestation of the decrease of hydroxyl. The NMR of carbon shows that the hemicellulose peaks are located at 23.36, 60.69, 74.83, 105.65 and 177 ppm, representing, respectively, C6 in methoxy, C2-C5 in polysaccharides, C4 in xylan, Cl in hemicellulose, and carbonyl carbon in the acetyl group [28]. According to Figure 5, except for the peak at 21 ppm, the peak intensity of other peaks decreased.…”

Section: Modification Reaction Mechanismmentioning

confidence: 93%

Modification Mechanisms and Properties of Poplar Wood via Grafting with 2-Hydroxyethyl Methacrylate/N,N′-methylenebis(acrylamide) onto Cell Walls

2023

Polymers

As the only renewable resource among the four basic materials (steel, cement, plastic, wood), wood itself and wood products have a “low carbon” value and play an important role in storing carbon. The moisture absorption and expansion properties of wood limit its application scope and shorten its service life. To enhance the mechanical and physical properties of fast-growing poplars, an eco-friendly modification procedure has been used. This was accomplished by the in situ modification of wood cell walls by vacuum pressure impregnation with a reaction of water-soluble 2-hydroxyethyl methacrylate (HEMA) and N,N’-methylenebis(acrylamide) (MBA). The anti-swelling efficiency of HEMA/MBA-treated wood was improved (up to 61.13%), whereas HEMA/MBA-treated wood presented a lower weight-gain rate (WG) and water-absorption rate (WAR). It was observed that the modulus of elasticity, hardness, density, and other properties of modified wood had improved significantly, as indicated by XRD analysis. Modifiers diffuse primarily within cell walls and cell interstices of wood, causing crosslinks between the modifiers and the cell walls, reducing its hydroxyl content and blocking the channels for water movement, thereby enhancing its physical properties. This result can be obtained by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX), Nitrogen adsorption test imaging ATR-FTIR (Attenuated total reflection-Fourier-Transform Infrared) Spectroscopy, and nuclear magnetic resonance (NMR) and Nitrogen adsorption test. Overall, this straightforward, high-performance modification method is crucial for maximizing wood’s efficiency and the sustainable development of human society.

“…In spite of the synthetic polymer, PEG can be fully biodegraded and is used in huge amounts . It was found that long chain PEG molecules were restricted to the cell lumen while the medium and shorter chain PEG molecules penetrated into the intercellular space of the cell wall in addition to the cell lumen . However, the water solubility of PEG would make it easier to leach and limited its utilization in outdoor conditions.…”

Section: Introductionmentioning

confidence: 99%

“…73 It was found that long chain PEG molecules were restricted to the cell lumen while the medium and shorter chain PEG molecules penetrated into the intercellular space of the cell wall in addition to the cell lumen. 74 However, the water solubility of PEG would make it easier to leach and limited its utilization in outdoor conditions. Trey et al improved the durability of PEG in the wood structure through electron-beam initiated polymerization of PEG-based monomers without a catalyst.…”

Section: ■ Introductionmentioning

confidence: 99%

Environmentally Benign Wood Modifications: A Review

Dong

ACS Sustainable Chem. Eng.

et al. 2020

Wood modification, an efficient approach to enhance the intrinsic properties of wood, has been extensively studied for decades. Due to growing environmental awareness, the sustainability of wood modification has received more attention. Generally, the sustainability in wood modification should consist of three aspects: an environmentally friendly processes, renewable modifying agents, and nontoxic and biodegradable resultant products. Recently, some biobased modifying agents obtained from renewable feedstocks were explored for substituting the petroleum-based ones. This review focuses on representative wood modification methods, including furfurylation, impregnation with natural products and biodegradable polymers, and chemical modification with sustainable reagents, since these methods have the potential to enhance wood properties. However, there are many challenges for using these agents, including effectiveness in penetration, evenness in distribution, and durability. The cost, process conditions, and equipment of these methods could also be challenges for scaling up. In addition, current studies mainly pay attention to the green reagent selection and property enhancement, rather than environment behavior evaluation of the resultant products. Effort should be made to evaluate the ecotoxicity and degradation behavior of the modified wood since it can help us determine whether the new formulations are sustainable. Much work needs to be done to overcome the obstacles above-mentioned and to develop efficient modification methods with a minimum environmental impact.