Formaldehyde Content Research Articles

Study on the Determination of Free Formaldehyde in Carbon-Coated Air Purifying Material by Water Extraction Method

The free formaldehyde in carbon-coated air purifying material was determined by water extraction method. The effects of solid-liquid ratio, extraction time and extraction temperature on the content of free formaldehyde in carbon-coated air purifying material were studied. In this paper, orthogonal tests and single factor tests were designed, and the optimal extraction conditions were 1:40 solid-liquid ratio, 90 min extraction time and 40 °C extraction temperature. Under this extraction condition, the relative standard deviation (n = 8) of the repeated test is 0.80%, and the recovery rate is 90%-100%, which indicates that the analytical method for determining the free formaldehyde in carbon-coated air purifying material by water extraction method is feasible.

Characterization of storage stability of resol resin solutions via gel time measurement and high-performance liquid chromatography

The influence of the temperature of storage on the proceeding polycondensationof commercial resol resin solutions was analyzed and it was found that results derived from a simple gel time measurements can provide the necessary information. It could be shown that resol resin solutions can be fitted into Arrhenius like models, which allow an extrapolation of the temperature-dependent changes of the material over arbitrary temperature ranges and hence estimation of the prolongation or reduction of declared shelf-life. High-performance liquid chromatographic analyses of the content of free phenol and free formaldehyde during storage could confirm and widely explain the observations from gel time measurements.

New insight into the use of latent catalysts for the synthesis of urea formaldehyde adhesives and the mechanical properties of medium density fiberboards bonded with them

Recently, there has been a rapid growth in research and innovation in the synthesis of UF resins in the wood-based composites area. Much effort has gone into increasing their mechanical performance to extend the capabilities and application of this group of materials. This paper, for the first time, defines the research on the use of ammonium salts not as hardeners but in the synthesis of UF resins. The objective of this study was to investigated the effects of various types of catalysts (ammonium sulfate, ammonium chloride, sulfuric acid and hydrochloric acid) during UF resins synthesis on formaldehyde emission and characteristics of urea–formaldehyde (UF) adhesives for the manufacture of medium density fiberboard. These were investigated by 13C Nuclear Magnetic Resonance (13C NMR) and differential scanning calorimetry (DSC), and as a result some of the physical and mechanical properties of medium density fiberboard (MDF) panels bonded with different UF resins were evaluated. The resins structure examined by 13C NMR spectroscopy showed that a resin catalyzed by (NH4)2SO4 had a higher proportion of hydroxymethyl groups (mostly HNCH2OH) resulting in a higher level of formaldehyde emission. A resin catalyzed by NH4Cl gave the highest proportion of methylene groups. A resin catalyzed by H2SO4 yielded the highest proportion of methylene groups in di- or tri-substituted ureas but the lowest proportion of mono-substituted urea. It was of interest that (NH4)2SO4 catalyzed UF adhesive yielded the best overall mechanical properties for the medium density fiber board (MDF) bonded with it. Conversely, it also presented the shortest shelf life and gelled in about 15 days, which could be related to its high reactivity and shortest gel time. Medium Density Fiberboard (MDF) panels bonded with UF adhesives without any ammonium salt (thus with either H2SO4 or HCl) had lower IB strength, MOR and MOE. The HCl catalyst was considered to be chemically least active, yielding the lowest cohesive energy, and resulted in panels presenting a poor performance as shown by their lowest IB (internal bond) strength, modulus of elasticity (MOE), and modulus of rupture (MOR) and highest thickness swelling, with the exception of the free formaldehyde content.

Hydrophilic Extracts of the Bark from Six Pinus Species

Pine barks are important biomass resources because they are utilised in the production of pine wood and rosins. However, no chemical study has been conducted on the hydrophilic status of pine barks in Indonesia. This aim of this study is to explore the hydrophilic extracts of the barks from six Pinus species (P. elliotii, P. caribeae, P. oocarpa, P. merkusii P. montezumae, and P. insularis). The hydrophilics of pine barks were analysed using gas chromatography-mass spectrometry. The presence of polyphenol contents in the ethanol extracts obtained from the barks of six Pinus species was determined using the tannin-formaldehyde method, Folin-Cioucalteu assay, and vanillin-HCl assay. The ethanol and hot water soluble extractives derived from inner barks were higher in quantity when compared to those derived from the outer bark samples. The polyphenol measurement showed that the highest value of total phenol content was derived from the outer bark of P. montezumae whereas those of the total phenol and tannin- formaldehyde contents were derived from the inner and outer barks of P. oocarpa. GC-MS analysis revealed that nitrogenous compounds are dominant constituents in the inner and outer barks of the six species, followed by sugars and monophenolics, respectively.

Effect of resin content and pressing temperature on banana pseudo-stem particle boards properties using full factorial design.

The volume of global gross banana exports reached a record of 117.9 million tonnes in 2015 (FAO 2017), which agro-industrial wastes derived as the pseudo-stem, rachis and leaves do not have an industrial application instead they are discarded. This research study applies full factorial design and response surface methodology to determine the effect of pressing temperature and resin content on density (D), moisture (M), water absorption (WA), water swelling (WS), module of rupture (MOR), module of elasticity (MOE) and formaldehyde content (FC) of particle board made of banana pseudo-stem. A 22 factorial design was performed, factors considered were resin and temperature. The low level of resin was 15% in the coarse fiber (CF) and 35% in fine fiber (FF); high level as 25% CF and 45% FF. Temperature levels were 150ºC and 170ºC respectively. The boards met all quality parameters except ones with low resin content that didn't meet WS parameter. Furthermore, resin affected positively on WA, FC and MOE, and decreased D, WS and MOR values. Meanwhile, temperature affected negatively on D, WS, and increased FC, WA, MOE, MOR properties; none of the factors affected M response. Process conditions were optimized to 162.61°C and 43.15% FF, 23.97% CF.

Evaluation of the Cytotoxicity of Commercially Available Nail Adhesives

Nail tips are nail art materials that can be attached to the nail with adhesives. Recently, nail/finger injuries related to nail tips have been reported and one of the causes is considered to be the adhesives used for attaching nail tips. The components of nail adhesives are mostly cyanoacrylate, which is also used as an industrial instant adhesive. During curing, cyanoacrylate adhesives release formaldehyde through hydrolysis. When it is marketed as a nail adhesive, there is no regulation regarding its formaldehyde amount nor obligation to indicate its ingredients in Japan. Additionally, a biological safety test is not required for nail adhesives. Thus, because the safety of nail adhesives is inadequately confirmed, it is necessary to investigate their biological safety. Therefore, we purchased 5 commercially available nail adhesives and 1 medical adhesive and examined their formaldehyde content and cytotoxicity. We examined the cytotoxicity of the adhesives in V79 cells by a colony forming assay. In this test, 5 nail adhesives showed higher toxicity than 1 medical adhesive. Formaldehyde concentrations in the extract of adhesives were as follows: 17.5 to 24.2 μg/mL for nail adhesives and 7.4 μg/mL for medical adhesives. Cyanoacetate did not elicit cytotoxicity at the final concentration up to 1000 μM. However, formaldehyde showed cytotoxicity, with an IC50 of 79 μM (2.4 μg/mL). Taken together, the cytotoxicity of nail adhesives could be due to the formaldehyde generated by the hydrolysis of cyanoacrylate. It seems important that nail adhesives will be regulated by obligation and enhanced safety in the future.

Effective Recovery of Pulp Waste in the Innovative Production of Environmentally Acceptable Wood Composites

However, as a result of efforts to improve the environment, while maintaining the required qualitative characteristics, global developments in the field of wood materials (as raw materials of the 21st century) have led to the development of new or effective modifications of existing technologies, focusing on reducing the emission of formaldehyde and other toxic components in polycondensation adhesives applied to the preparation of composite wood materials. The suggested problem means reciprocal replacement of the toxic components of currently produced polycondensation adhesives (especially phenol-formaldehyde), e.g. kraft black liquors, which can be isolated as a secondary raw material from the pulp and paper industry in the production of sulphate pulp. Sulphate liquros are characterized by a relatively low reactivity to formaldehyde, thus are requiring their incorporation into the polymeric matrix of mixed lignin-phenol-formaldehyde polycondensate. For this reason, it is necessary to modify the reactivity of the original kraft black liquors by the modification reactions. New methods of processing sulphate liquors are focused only on the use of some components of black liquors or on the production of high-price products, which can be applied economically but especially “eco-friendly” in the preparation of wood composite materials as adhesives. The article deals with the problem of effective utilization waste of kraft black liquor from pulp and paper industry, which are possible apply in various modification treatment as reciprocal replacement of polycondensative adhesives for preparation of wood based composite materials. In our research, we focused on proposal of innovative adhesives mixtures which were applied for production of eco-progressive wood based composite materials with better hygienical properties and significantly reducing the content of toxic formaldehyde in adhesive mixtures.

新建本科院校室内空气中甲醛含量的现状及影响因素与治理措施

新建本科院校室内空气中甲醛含量的现状及影响因素与治理措施

Effect of different acids during the synthesis of urea‐formaldehyde adhesives and the mechanical properties of medium‐density fiberboards bonded with them

ABSTRACTThe characteristics of urea‐formaldehyde (UF) adhesives condensed by catalysis with four different acids, namely formic (HCOOH), hydrochloric (HCl), phosphoric (H3PO4), and sulfuric (H2SO4) acids, under alkaline–acidic–alkaline conditions at a molar ratio F/U = 1.12 were studied. The thermal curing properties of UF adhesives catalyzed with acid were characterized by differential scanning calorimetry at 10 °C/min heating rate. The resin structure examined by 13C‐NMR spectroscopy showed that the resin catalyzed with HCl had a lower proportion of methylol groups, resulting in a lower level of formaldehyde emission. It was interesting to note that HCOOH resulted in the best overall mechanical properties of the medium‐density fiberboard (MDF) panels. The HCl catalyst resulted in the poorest performance, providing the lowest internal bond strength, modulus of elasticity, and thickness swelling, with the exception of the free formaldehyde content. The resin catalyzed with H2SO4 had the highest free formaldehyde and the highest formaldehyde emission. H2SO4 and H3PO4 resulted in MDF mechanical properties relatively lower than for HCOOH. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47256.

A novel method for rapid quantitative evaluating formaldehyde in squid based on electronic nose

The aim was to establish a rapid and quantitative detection method of formaldehyde in squid based on electronic nose for screening massive samples. Identification of volatile compounds in squid with different formaldehyde content by electronic nose were mainly depended on eight sensors. Besides, the diversities of volatile constituents in squid with increasing contents of aldehydes and aromatic compounds were validated by GC-MS results. Moreover, to build a qualitative discrimination model for estimating whether formaldehyde in squid over standard limit or not, DFA and SIMCA based on PCA were used to analyze electronic nose data for semi-quantitative determination of formaldehyde content in squid. Finally, a rapid quantitative prediction model based on electronic nose and PLS was established (R2 = 0.9266).To verify the accuracy of quantitative model, t-test was employed and no significant difference between predicted values and true values was found. This approach showed well potentiality to provide a rapid, nondestructive and quantitative method for detecting formaldehyde residue in food.

Development and performance study of a new shrink-proof and non-iron cotton blended fabric

The approaches for cotton shrink-resistant finishing can be categorized into chemical finishing and physical finishing. In this research, a new approach to prevent cotton fabric from shrinkage and wrinkling without resin finishing was studied to reach an easy care effect of “wash-and-wear” for related end products. It was achieved by adding a certain proportion of fine denier polyester and memory polyester fibers. Unlike the previous chemical finishing methods, this physical finishing method does not cause yellowing, formaldehyde content increase or strong damage of tensile strength. It can reduce the shrinkage rate and increases the wrinkle recovery angle (WRA) through the shape memory formed by the memory polyester fiber in the heat setting stage. Our results were of better condition with significant improvements in WRA, anti-pilling effect, shrink-proofing and strength of the fabrics. The fabrics can be widely used in bedding textiles and shirting fabrics.

Risk Assessment of Kumasi Metropolis Population in Ghana through Consumption of Fish Contaminated with Formaldehyde.

This study evaluates the exposure of the Ghanaian population of the Kumasi Metropolis of Ghana to formaldehyde through the consumption of fish using 3-Methyl-2-Benzothiazoline Hydrazone method, with trichloroacetic acid as an extracting agent. A total of sixty (60) fish species comprising both local and imported fish were bought from cold stores and fish ponds were analysed. Formaldehyde was found in all the species analysed with concentration ranging from 0.174 to 3.710 μgg−1. However, the levels were still lower than 5 mg/kg, which is the maximum limit established by the Malaysian Food Act and Regulation for formaldehyde in fish. The estimated daily intake values for formaldehyde in the fish species analysed ranged between 4.233 × 10−4 and 3.661 × 10−3 mg/kg BW/day and this was less than the acceptable daily intake of 0.15 and 0.2 mg/kg BW/day suggested by World Health Organization and the United States Environmental Protection Agency for formaldehyde intake, respectively. The results for the hazard quotient calculated for all the species were less than one suggesting that the amount of formaldehyde in the fish is not likely to pose any potential adverse health effects to consumers. Thus, wet fish from Kumasi may be considered safe for consumption because of low formaldehyde content.

Human Endogenous Formaldehyde as an Anticancer Metabolite: Its Oxidation Downregulation May Be a Means of Improving Therapy.

Malignant cells are characterized by an increased content of endogenous formaldehyde formed as a by-product of biosynthetic processes. Accumulation of formaldehyde in cancer cells is combined with activation of the processes of cellular formaldehyde clearance. These mechanisms include increased ALDH and suppressed ADH5/FDH activity, which oncologists consider poor and favorable prognostic markers, respectively. Here, the sources and regulation of formaldehyde metabolism in cancer cells are reviewed. The authors also analyze the participation of oncoproteins such as fibulins, FGFR1, HER2/neu, FBI-1, and MUC1-C in the control of genes related to formaldehyde metabolism, suggesting the existence of two mutually exclusive processes in cancer cells: 1) production and 2) oxidation and elimination of formaldehyde from the cell. The authors hypothesize that the study of the anticancer properties of disulfiram and alpha lipoic acid - which affect the balance of formaldehyde in the body - may serve as the basis of future anticancer therapy.

An environmental polyurethane retanning agent with the function of reducing free formaldehyde in leather

Chromotropic Acid Grafted Amphoteric Polyurethane (CAGAPU) was synthesized with Chromotropic Acid (CA) as a modifier for Polyurethane (PU). The structure of CAGAPU was confirmed by FT-IR, 1H-NMR. The retanning process and the experiments of CAGAPU with formaldehyde indicate the following: (1) The leather retanned by CAGAPU can be comparable or surpassed to the market PU-based retanning system in terms of shrinkage temperature and sensory performance. (2) The leather collagen fibers are smoother and orderly which provides a potential value for the appearance of the leather and fur industry. (3) The CAGAPU retanned system can bring down the free formaldehyde content in aldehyde tanned leather significantly. (4) The optimum dosage of CAGAPU is 20 g and the best retanning time is 6 h (5) The CAGAPU retanned system can reduce the free formaldehyde, Biochemical Oxygen Demand (BOD), Total Dissolved Solids (TDS) and Total Suspended Solid (TSS) from the source which retard pound on the economy and environment greatly compare to the traditional governance. Therefore, this paper provides the possibility for the sustainable development of leather. The work has changed the traditional way of “terminal treatment” and realized the “initial treatment” and may also offer a new idea of solving the problem of formaldehyde in the newly decorated houses or in the air.

Partial replacement of melamine by benzoguanamine in MUF resins towards improved flexibility of agglomerated cork panels

Melamine-urea-formaldehyde (MUF) resins are highly effective adhesives for lignocellulosic materials. However, their high stiffness hinders applications where flexibility is desired. In this work, MUF resins were modified with benzoguanamine by partially replacing melamine in two different steps of the synthesis. The purpose was to obtain a less densely crosslinked, and hence more flexible, structure after cure. All modified MUF resins were characterized using gel permeation chromatography (GPC). Results suggest that benzoguanamine and its derivatives were integrated into the polymer structure. FTIR and 13C-NMR analysis confirmed the presence of benzoguanamine in the modified resins. The addition of benzoguanamine to the MUF resin synthesis significantly improved the flexibility of agglomerated cork panels bound with modified resins. The minimum mandrel diameter on which the panels could be bent by 180° without failure decreased from 18 mm to 12 mm diameter, while the remaining key properties of the panels were maintained (tensile strength and boiling water resistance). The formaldehyde content of the panels (determined according to EN120) corresponds to E1 class.

Feasibility of Biological Monitoring of Anatomy Laboratory Staff Exposed to Formaldehyde

Background: Formaldehyde (FA) is a reactive carcinogenic compound and is used routinely in anatomy theatres. Recently, biological monitoring is introduced as a method of choice for monitoring of exposed workers to hazardous chemicals with systemic absorption. Objectives: Considering the toxicity of formaldehyde and lack of a comprehensive method for its biological monitoring, the aim of this study was to explore a new and non-invasive method for biological monitoring of formaldehyde exposure in the staffs of anatomy theatre. Methods: This study was a cross-sectional investigation and the population of this study was comprised of 20 exposed staffs in an anatomy theatre in Tehran, Iran. The personal monitoring of 20 staff was carried out during the early winter, according to a method from the National Institute of Occupational Safety and Health No. 2016. Biological monitoring was conducted by measuring FA in staff’s exhaled breath after termination of the work shift. The data obtained were statistically analyzed using correlation analysis. Results: The mean FA personal exposure and its concentration in the exhaled breath of anatomy’s staffs were 698 ± 34 and 195 ± 17 as ppb, respectively. Correlation of staff’s personal exposures to formaldehyde with the excreted formaldehyde in their exhaled breath was statistically significant (P < 0.001). Conclusions: The present study showed that the personal exposure of staffs to the FA was higher than the permissible exposure limit. Statistically significant positive correlation of staff exposure with the content of FA in their exhaled breath indicated the potential of biological monitoring of exposed group to FA through exhaled breath.

Volatile organic compounds (VOCs) from lauan ( Shorea ssp.) plyboard prepared with kraft lignin, soy flour, gluten meal and tannin: emissions during hot pressing and from panels as a function of time

Abstract Soy and corn gluten proteins are common ingredients in adhesives and resins together with kraft lignin and condensed tannin. The relative contribution of these additives to volatile organic compound (VOC) emissions in the course of processing hardwood veneer products was evaluated. Press emissions were captured and separated into condensate and gaseous fractions. High-performance liquid chromatography (HPLC) was employed to characterize aldehydes in condensate and gaseous fractions, while GCMS served for identification and quantitative determination of the compounds in the gas phase. Aldehydes dominate the press emissions with both proteinaceous binders producing significantly higher formaldehyde (FA), acetaldehyde (AcA) and hexaldehyde (hexA) emissions compared to pressed veneer without additives. Other aldehydes, including valeraldehyde and propionaldehyde were also captured, but in relatively lower amounts. In contrast, lignin as a binder led to lower FA content in press emissions, whereas tannin significantly reduced contributions of FA, AcA and other aldehydes. VOC emissions from plywood panels during chamber testing were similar to compounds evolved on hot-pressing.

COMPARATIVE INVESTIGATION OF GENOTOXIC ACTIVITY OF GLYPHOSATE TECHNICAL PRODUCTS IN THE MICRONUCLEUS TEST IN VIVO

Glyphosate is one of the most widely used herbicides in the world. In recent years, there have been concerns about the possible mutagenicity and carcinogenicity of this pesticide. In this connection, the study of genotoxic and carcinogenic properties of glyphosate and glyphosate-containing preparations has been resumed in a number of countries. In this study, the induction of micronucleation formation in vivo in polychromatophilic erythrocytes of bone marrow of CD-1 mice was assessed by the action of three different technical glyphosate products entering the Russian Federation. It was found that the tested samples of technical products showed different cytogenetic activity, while only one of them caused a statistically significant, dose-dependent increase in the frequency of induction of micronuclei compared to the negative control. The analysis of the composition of the studied product samples showed that the cytogenetic activity may depend on the content of potentially mutagenic impurities, in particular formaldehyde. The obtained data are additional grounds for lowering the upper limit of formaldehyde content in technical products of glyphosate and also indicate the need to assess the genotoxic activity of analog pesticides entering the market of plant protection products.

Introducing flexibility in urea–formaldehyde resins: Copolymerization with polyetheramines

ABSTRACTAdhesives obtained by copolymerizing urea, formaldehyde, and difunctional polyetheramine with different molecular weights (230, 600, 900, and 2000 g mol−1) are presented as a more resilient alternative to conventional urea–formaldehyde resins. Urea and polyetheramine contents were varied and the resulting resins characterized by FTIR, 13C‐NMR, and TGA. These resins were used for production of agglomerated cork panels, an application that demands that the binder system is flexible. Polyetheramine with molecular weight 900 g mol−1 yielded the most promising agglomerated cork panel, with remarkable flexibility, good tensile strength, and with the E1 formaldehyde content specification for wood‐based panels used in construction, according to European Standard EN 12460‐5. These new thermoset adhesives have demonstrated to be capable of being used in systems where conventional formaldehyde‐based resins do not perform well due to inherent high rigidity. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1834–1843

The effects of huntite–hydromagnesite inclusion in acrylate-based polymer paste coating process on some textile functional performance properties of cotton fabric

In this study, cotton fiber fabrics were coated with polyacrylate-based polymer paste containing huntite–hydromagnesite by knife over roll process. The flame retardancy properties of the cotton fabrics were tested according to vertical flame test, limit oxygen index (LOI) test, smoldering cigarette and match flame tests. Thermal behavior of cotton fabrics was investigated by DTA–TG analysis. The antibacterial activities of coated cotton fabrics were qualitatively determined according to AATCC Method 147. Mechanical properties of cotton fabrics were evaluated with the help of tear strength, abrasion strength, thickness and stiffness measurements. Air permeability, UV protection and color properties were also investigated. Free formaldehyde content of the coatings on cotton fabrics were determined according to Japanese Law 112. The microstructural properties of cotton fabrics were characterized using SEM and FTIR (ATR) analysis. Furthermore, the mineral content and mean particle size value of huntite–hydromagnesite were also determined with X-ray fluorescence spectrometer and particle size analyzer. The flame retardancy and antibacterial properties of the cotton fabrics were improved after coating with acrylate-based polymer paste containing huntite–hydromagnesite. Mechanical properties such as tear strength of the cotton fabric decreased after coating process however huntite–hydromagnesite addition into coating paste did not lead to further increase on the tear strength loss of cotton fabric. Despite this, the resultant maximum abrasion cycles significantly increased following coating process application. Furthermore, colorimetric properties such as whiteness and lightness of cotton fabric did not significantly change after applied coating processes. SEM and FTIR analyses confirmed the constancy of microstructure of cotton fibers after coating process.