Transforming tree topping waste into flooring: a study on the production and evaluation of oriented strand board finish using urban and garden residues

Oriented strand board (OSB) has become a popular building material for residential construction, but little research has been conducted on its use as a finish floor material. The study investigated the quality and performance of OSB as an alternative to traditional engineered wood products for finish floors. Four types of OSB finish floors using a mixture of garden and urban tree toppings were produced and evaluated, along with different types and levels of resin and mat moisture content. The finish floor panels were subjected to a battery of tests, including concentrated loading, indentation, falling ball impact resistance, abrasion resistance, and surface wettability. The findings showed that urea formaldehyde resin with garden tree toppings performed best in floor surface indentation, abrasion resistance, and falling ball indentation. The phenol formaldehyde resin with garden tree toppings, on the other hand, showed less moisture absorption and swelling during surface wetting tests and better resistance to force application in the concentrated loading test. Our qualitative comparison revealed that OSB finish floor production using 100% garden tree topping strands and 12% urea formaldehyde resin, along with 14% mat moisture content, produced the best results. The study provides valuable insights into the potential use of OSB as a sustainable and cost-effective finish floor material, using waste materials from urban and garden tree toppings.

Formaldehyde and VOC emissions from plywood panels bonded with bio-oil phenolic resins

Pyrolysis bio-oil was used to partially substitute for phenol in reacting with formaldehyde for the production of bio-oil phenol formaldehyde plywood (BPFP) panels, with the phenol substitution ratio being 20%, 40%, or 60%. Emissions of formaldehyde and volatile organic compounds (VOCs) from the BPFP panels were studied using solid-phase micro-extraction (SPME) followed by headspace gas chromatography/mass spectrometry (GC/MS), and were compared to those from the phenol formaldehyde plywood (PFP) panels. The sources for VOCs were analyzed, and the health risks associated with the BPFP were examined. Results showed that at 80 °C: (1) Formaldehyde emissions from the BPFP panels were increased to about 4 times that of PFP; (2) VOCs emissions were significantly reduced by up to 84.9% mainly due to the greatly reduced phenol emissions, although the total number of VOCs was increased from 20 to 35; (3) BPFP presents greatly increased carcinogenic and non-carcinogenic health risks because of its much stronger emissions of formaldehyde, N,N-dimethylformamide, benzofuran, furfural, and many chemicals from the bio-oil. It is highly advisable that the health risks are properly taken care of before the wide application of BPFP, or similar bio-oil based engineered wood products.

Turn-on fluorescent sensor for the detection of glucose using manganese dioxide-phenol formaldehyde resin nanocomposite

Monitoring blood glucose has attracted considerable attention because diabetes mellitus is a global public health problem. Herein, we reported a turn-on fluorescence detection strategy based on manganese dioxide (MnO₂)-phenol formaldehyde resin (PFR) nanocomposite for rapid, sensitive, and selective detection of glucose levels in human blood. In this biosensing system, MnO₂ nanoshell on the PFR nanoparticle surfaces serve as a quencher. PFR fluorescence can make a recovery in the presence of H₂O₂, reducing MnO₂ to Mn²⁺. The sensor shows a linear range from 50nM to 90μM with a low detection limit of 20nM for H₂O₂ detection. Thus, the glucose can be detected on the basis of the enzymatic conversion of glucose by glucose oxidase to produce H₂O₂. This method exhibits a wide linear range from 5μM to 1mM with a low detection limit of 1.5μM. Because of the excellent photostability offered by PFR, the developed strategy has been successfully applied for the diagnosis of diabetes mellitus in human blood samples. Compared with commercial glucometer, our method showed satisfactory results, indicating the significant reliability. The developed turn-on fluorescent sensor might hold great promise in nanomedicine and bioanalysis.

Exploring the potential of high resolution mass spectrometry for the investigation of lignin-derived phenol substitutes in phenolic resin syntheses

Chemical degradation is an efficient method to obtain bio-oils and other compounds from lignin. Lignin bio-oils are potential substitutes for the phenol component of phenol formaldehyde (PF) resins. Here, we developed an analytical method based on high resolution mass spectrometry that provided structural information for the synthesized lignin-derived resins and supported the prediction of their properties. Different model resins based on typical lignin degradation products were analyzed by electrospray ionization in negative ionization mode. Utilizing enhanced mass defect filter techniques provided detailed structural information of the lignin-based model resins and readily complemented the analytical data from differential scanning calorimetry and thermogravimetric analysis. Relative reactivity and chemical diversity of the phenol substitutes were significant determinants of the outcome of the PF resin synthesis and thus controlled the areas of application of the resulting polymers. Graphical abstract ᅟ.

Adsorption characteristics of polycyclic aromatic hydrocarbons from non-aqueous media using activated carbon derived from phenol formaldehyde resin: kinetics and thermodynamic study

Porous carbons were prepared by carbonization and activation of phenol formaldehyde resin by gasification with CO₂ at 900 °C. Prepared activated carbon from phenol formaldehyde was characterized by measuring thermogravimetry (TG), differential thermal analysis (DTA), pH, surface area, porosity, and pore size distribution. The specific surface area (SSA) of these carbons ranges from 562 to 1904 m²/g, while their point of zero charge (pHPZC) varies from 2.6 to 8.8. The ability of the prepared activated carbon by gasification with CO₂ at 900 °C from phenol formaldehyde resin (PFAC) to remove a series of polycyclic aromatic hydrocarbons (PAHs), e.g., naphthalene, fluorene, phenanthrene, pyrene, and fluoranthene, from mixtures of organic solvents with different polarities and chemical structures was tested. The adsorption capacity increases with the increasing the SSA and pHPZC of the carbons, confirming the roles of dispersive interactions. The kinetics and thermodynamics of the adsorption of phenanthrene as a model compound of PAH on PFAC in the organic solvent were studied. The adsorption capacity became notably greater with an increase in contact time and initial phenanthrene concentration.