Formaldehyde Release Research Articles

THE SOY FLOUR AS AN EXTENDER FOR UF AND MUF ADHESIVES IN BIRCH PLYWOOD PRODUCTION

Formaldehyde emission still remains a major disadvantage of widely applied formaldehyde-containing amino resins such as UF (urea-formaldehyde) resin and MUF (melamine-urea-formaldehyde) resin. The compositions of adhesives for plywood manufacturing have to contain a proper extenders in order to adjust their viscosity. Thus, the aim of the study was to investigate the effect of protein-rich soy flour (SF) as the extender for adhesives. The composition of flours and their ability to absorb the formaldehyde were determined. Properties of liquid resins such as gel time, viscosity, pH and solid content were investigated. The possible chemical interaction between the extenders and resins were assessed with the use of FTIR spectroscopy. Plywood panels manufactured using UF and MUF adhesives with the soy flour introduced as the extender in various concentrations were tested in terms of shear strength and formaldehyde release. Studies have shown that soy flour has a favorable composition and formaldehyde-scavenging ability. The addition of SF affected resins properties such as viscosity and gel time but showed no influence on their pH and solid content. FTIR analysis has not explained the chemical interaction between resin and extender. The application of soy flour in the concentration of 15% for UF resin and 10% for MUF resin allowed to produce plywood characterized by improved bonding quality and decreased formaldehyde emission.

Utilization of activated carbon as an additive for urea-formaldehyde resin in medium density fiberboard (MDF) manufacturing

In this study, the MDF sanding dust was examined as a precursor for synthesizing activated carbon (AC). For this purpose, MDF sanding dust was impregnated with KOH at two different weight ratios 1:0.50 and 1:1 (sanding dust/KOH). The process was done in one step at a temperature of 750 °C and a heating rate of 8 °C/min. The synthesized ACs at different content were added into urea-formaldehyde (UF) resin for medium density fiberboard (MDF) production. The laboratory MDF boards were produced using a hot press at a temperature of 190 °C and pressure of 40 MPa. The ACs content in UF resin was set at 0.25%, 0.50% and 1% based on the dry weight of the resin. The ACs were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The BET equation was used to determine the specific surface area of the AC samples. Water absorption, thickness swelling, internal bonding, flexural modulus and strength, and the formaldehyde emission from MDF boards were determined. The curing behavior of UF resins were evaluated using Differential Scanning Calorimetry (DSC). The results revealed that surface area and micropore volume of ACs increase with increasing KOH ratio; and the ACs exhibited three-dimensional porous network structures. The DSC results also showed that the ACs significantly increase the reaction enthalpy of UF resins. The addition of AC as an additive to UF resin significantly reduces formaldehyde release from MDF boards and improves their physical and mechanical properties.

Polyphenol-Metal Ion Redox-Induced Gelation System for Constructing Plant Protein Adhesives with Excellent Fluidity and Cold-Pressing Adhesion.

Soy protein (SP) adhesives can resolve several problems with aldehyde-based adhesives, including formaldehyde release and excessive dependence on petroleum-based materials. Nevertheless, their development is hindered by the lack of balance between fluidity and high cold-pressing adhesive strength. A dynamically cross-linked SP adhesive with excellent fluidity and cold-pressing adhesion was developed in this study based on the polyphenol-metal ion redox-induced gelation system. SP was blended with acrylamide (AM), ammonium persulfate (APS), and the tannic acid (TA)-Fe3+ complex to prepare an adhesive gel precursor with good fluidity. In situ gelation of SP adhesive was then achieved via AM polymerization, as initiated by redox between TA and Fe3+. As expected, the prepared adhesive gel exhibited outstanding cold-pressing bonding strength (650 kPa) to the veneers compared to the neat SP adhesive, which has almost no cold-pressing bonding strength to the veneers. The TA-Fe3+ complex induced an in situ gelation system, which endowed the SP adhesive with strong cohesion; the topological entanglement of the adhesive gel in the veneers contributed to tight interfacial combinations. The TA-Fe3+ complex served not only as an accelerator of SP adhesive gelation but also as a "cross-linking core" for the cross-link SP adhesive system. The prepared SP-based adhesive also exhibited outstanding hot-pressing bonding strength and mildew resistance. The proposed polyphenol-metal ion-induced in situ gelation strategy may provide a new approach for developing advanced vegetable protein adhesives to replace aldehyde adhesives.

Scleral growth stunting via sub-Tenon injection of cross-linking solutions in live rabbits

BackgroundScleral cross-linking is a potential method to inhibit axial elongation of the eye, preventing the progression of pathological myopia. Formaldehyde releasers, which are common preservatives found in cosmetics and ophthalmic...

Analytical Method Development for Determining Formaldehyde in Cream Cosmetics Using Hyphenated Gas Chromatography.

Formaldehyde has been reported to be a potential human carcinogen due to its toxicity. However, formaldehyde releaser substances are still widely used as a preservative in cosmetics. Researchers have developed various methods for determining formaldehyde. One of the problems involved in the standard method is that of obtaining a derivatization agent, especially for routine analysis in the National Agency of Drug and Food, Indonesia. Therefore, this study aimed to develop a new method using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID). The significant modifications involved optimizations of five series of concentrations of p-toluenesulfonic (PTS) acid in ethanol (acidified ethanol), used as the derivatization agent, and the conditions of time and temperature of the reaction to yield the highest peak area. In addition, sample analysis was also carried out using the 2,4-dinitrophenylhydrazine (DNPH) method with high-performance liquid chromatography (HPLC) to compare the quantification results. The validated method showed intraday and interday precision, an accuracy (% RSD) of less than 3.7%, confidence interval 95.0–105.0%, a limit of detection and quantitation of 0.0099 and 0.0329 μg/mL (for DNPH by HPLC-DAD), 0.0158 and 0.0528 μg/mL (for PTS by SHS-GC-MS), and 1.1287 and 3.7625 μg/mL (for PTS liquid by GC-FID), respectively. These results have met the requirements for a validated analytical method and could be applied for routine analysis.

Bio-based composites fabricated from wood fibers through self-bonding technology

Green composite processing technology of wood fibers is an inevitable choice for global sustainable development. In this research, waste poplar powder with different particle sizes was used to prepare glue-free biocomposites with good mechanical and waterproof properties by hot-molding. The biocomposites made of larger size wood powder had better tensile strength (40.3 MPa) and the biocomposites made of smaller size wood powder had the greater bending strength (50.5 MPa). The thickness swelling rate of the biocomposites was only 4.26% after soaking in water for 24 h. The cross-section morphology of the biocomposites showed that the cell wall collapses enhanced the interfacial bonding. Chemical analysis showed that lignin repolymerized with cellulose and hemicellulose for the vitrification transition. In addition, the biocomposites with excellent mechanical properties had no formaldehyde release, which can replace the traditional density boards made of adhesives and applied as furniture materials and in line with the concept of cleaner production.

Mechanical Properties and Formaldehyde Release of Particleboard Made with Lignin-Based Adhesives

The aim of this research was to evaluate the potential of magnesium lignosulfonate as adhesive in particleboard manufacturing. Diphenylmethane diisocyanate (PMDI) between 1% and 3% and glucose (1% of the lignosulfonate content) were added as potential cross-linkers in the adhesive formulations. Mixed beech and spruce wood, 30% beech wood and 70% spruce wood, were employed for the configuration of the panel structure. The density, mechanical properties and formaldehyde emission of single-layer particleboard were investigated. Spectroscopic analysis (FTIR) revealed structural changes brought by oxidation that may indicate depolymerization by the splitting of C-O-C bonds and formation of carbonyl groups. Mechanical properties were improved, and the highest average values were recorded for panels having as adhesives oxidized lignin with cross-linkers as follow: 15 N/mm2 (MOR), 3320 N/mm2 (MOE) and 0.48 N/mm2 (IB). The density profile presented higher values for faces in case of oxidized lignin panels. Changes were observed for oxidized lignin with cross-linker panels wherein the core had higher values. The results showed that the panels manufactured with adhesives composed of oxidized lignosulfonate (20% of the dried wood particles weight) and the addition of PMDI and glucose in various percentages have a positive influence on their formaldehyde release and mechanical properties requested by EN 312 (2004) standard.

Strategic hazard mitigation of waste furniture boards via pyrolysis: Pyrolysis behavior, mechanisms, and value-added products

Waste furniture boards (WFBs) contain hazardous formaldehyde and volatile organic compounds when left unmanaged or improperly disposed through landfilling and open burning. In this study, pyrolysis was examined as a disposal and recovery approach to convert three types of WFBs (i.e., particleboard, plywood, and fiberboard) into value-added chemicals using thermogravimetric analysis coupled with Fourier-transform infrared spectrometry (TG-FTIR) and pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS). TG-FTIR analysis shows that pyrolysis performed at an optimum temperature of 250–550 °C produced volatile products mainly consisting of carbon dioxide, carbon monoxide, and light hydrocarbons, such as methane. Py-GC/MS shows that pyrolysis at different final temperatures and heating rates recovered mainly phenols (25.9–54.7%) for potential use as additives in gasoline, colorants, and food. The calorific value of WFBs ranged from 16 to 18 MJ/kg but the WFBs showed high H/C (1.7–1.8) and O/C (0.8–1.0) ratios that provide low chemical energy during combustion. This result indicates that WFBs are not recommended to be burned directly as fuel, however, they can be pyrolyzed and converted into solid pyrolytic products such as biochar with improved properties for fuel application. Hazardous components, such as cyclopropylmethanol, were removed and converted into value-added compounds, such as 1,4:3,6-dianhydro-d-glucopyranose, for use in pharmaceuticals. These results show that the pyrolysis of WFBs at high temperature and low heating rate is a promising feature to produce value-added chemicals and reduce the formation of harmful chemical species. Thus, the release of hazardous formaldehyde and greenhouse gases into the environment is redirected.

The development of dual-function solid-phase method as extraction and a decomposition reaction media for the determination of a formaldehyde releaser, imidazolidinyl urea, in cosmetics

In this study, we present a simple method to determine imidazolidinyl urea (IU) in cosmetics using a solid phase as both a decomposition field and an extraction phase. IU is difficult to quantify because it is a mixture of allantoin–formaldehyde condensation products that are easily decomposed to release formaldehyde. In our method, IU is decomposed to allantoin and 1-[4-(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl]urea (4-HU) on an aminopropyl-bonded silica solid phase. Subsequent high-performance liquid chromatography enables quantification of the resulting allantoin and 4-HU. The quantified value was converted to the total allantoin amount on the basis of molecular weight, and the calculated value was compared with that of an IU reference standard to determine the contents. The calibration curves of the decomposed IU as allantoin and 4-HU were both linear over an IU solution concentration range from 0.05 to 0.65% (w/v). The recoveries from lotion, body soap, and conditioners, which contained 0.1%, 0.3%, and 0.6% (w/w) of IU, respectively, ranged from 88.2 to 107.5%. The relative standard deviation values for the recovery tests of six replicates ranged from 1.03 to 6.97%. The intra-laboratory precisions for the lotion and conditioner A containing 0.3% IU were 3.02 and 4.94%, respectively. This method was well validated and would be helpful in determining IU in cosmetic samples.

Effect of Using Urea Formaldehyde Modified with Extracts in Plywood on Formaldehyde Emission

Formaldehyde-based adhesives are used in the forestry industry. This is because formaldehyde is inexpensive, easy to use and resistant to moisture; it also has particular mechanical effects. Formaldehyde has both advantages and disadvantages. It is known that various diseases such as lung cancer occur in humans as a result of the release of formaldehyde into the air during and after board production. In this study, a urea formaldehyde glue mixture was prepared by using four different fillers (extract of maritime pine (Pinus pinaster) and elm (Ulmus glabra) bark, extract of hazelnut (Corylus avellana) husk and acorn tannins) at two different ratios. The bonding shear strength of pine (Pinus sylvestris) and spruce (Picea orientalis) plywood produced with urea formaldehyde adhesive was tested according to EN 314-1 standard. All plywood, except the plywood with acorn tannin, met the requirements of the standard. A formaldehyde emission test of the plywood was carried out in accordance with EN 713-3 standard. With this approach, it is possible to quickly determine formaldehyde emissions. Experimental results were obtained for subsequent measurements, including chamber tests. It was observed that the elm bark extract reduced the formaldehyde emission of pine plywood by 40 %, while other fillers reduced it by 3-37 %.

Adhesiveless bonding of wood – A review with a focus on wood welding

Most industrially used synthetic wood adhesives release formaldehyde, which is carcinogenic for humans. Adhesiveless bonding of wood can be achieved using heat treatment by either hot-pressing method, suitable mainly for wood particles and fibres or by wood welding. Welding of wood, which relies on the heat generated via friction, can be used for bonding two or more solid wood pieces together. The process can be carried out either by linear or rotational wood welding. This review first considers the manufacturing of binderless wood-based panels by hot-pressing. Then this is followed by an in-depth outlook of wood welding and its application in the wood industry. The effects of varying wood welding parameters, such as applied pressure, vibrational frequency and amplitude, holding pressure, holding time, welding time in linear wood welding, and relative diameter difference between the substrate and the dowel in rotational wood welding to obtain joints with optimal mechanical and physical properties is reviewed and discussed. Wood products made by heat treatment (hot-pressing and wood welding) are environmentally friendly, and the brief curing times needed for their manufacture represent a great advantage compared with the usage of wood adhesives to bind pieces of wood.

Review on natural and synthetic preservatives for herbal face wash formulations

The skin is the most exposed organ liable for providing a barrier to the external environment which will resist a good range of challenges of microbial agents and infectious agents (pathogens). Chemically synthesized drugs and additives were utilized to prepare the herbal formulation like acne face washes, antibiotic gel, and also masks are presently dominating in the market. Surprisingly these synthetic medications have several side effects and fail in treating the disease or compete with pathogenic agents. The microbiological safety has as main goal of consumer protection against potentially pathogenic microorganisms, this is ensured by chemical, physical, or physicochemical strategies. The most common strategy is based on the application of antimicrobial agents, either by using synthetic and natural compounds or multifunctional ingredients. Among the preservatives described in the positive list of regulations there are parabens, isothiasolinone, organic acids, formaldehyde releasers Triclosan and chlorhexidine chemical agents have different of antimicrobial action, this review also concentrate on natural preservatives like lemon, honey, neem, aloe vera, turmeric and sugar.

Optimizing content of Pyrovatex CP New and Knittex FFRC in flameretardant treatment for cotton fabric

In this study, the flame-retardant treatment for cotton fabric has been done by using the commercial organophosphoruscompounds labelled Pyrovatex CP New (PR). Knittex FFRC (K), a formaldehyde-free crosslinking agent, has been usedto enhance the link between Pyrovatex CP New and Cellulose molecules. The flame-retardant treatment process forcotton fabric has been done by the pad-dry-cure technique. The purpose of the study is to predict the optimal PyrovatexCP New and Knittex FFRC concentrations with the highest fire resistance efficiency, minimum loss for mechanicalproperties and minimum formaldehyde release for the treated fabric. To achieve this goal, the response surfacemethodology (RSM) was used to find the relationship between the controlled experimental factors and the observedresults. The central composite design type face centred (CCF) was applied as experimental design. According to thisexperimental design, 10 experiments were carried out. The chemical uptake rate, vertical flammability characteristics,LOI value, tensile strength and formaldehyde-free content of the untreated and treated samples were determined. Fourresponse models between the reagent concentrations and the add-on amount, LOI value, warp and weft tensile strengthof the treated fabric were obtained by the assistance of software Design-Expert V 10.0.8. The R-squared values of thesemodels were above 80% confirming their significances. The optimal conditions when combining three parameters (LOI,warp tensile strength and weft tensile strength) were selected as 450 g/l Pyrovatex CP New and 107,575 g/l KnittexFFRC with the assistance of Design-Expert software

Clinical manifestations and patch test results for facial dermatitis associated with disposable face mask use during the COVID-19 outbreak: A case-control study

Clinical manifestations and patch test results for facial dermatitis associated with disposable face mask use during the COVID-19 outbreak: A case-control study

Patterns of positive patch test reactions to formaldehyde and formaldehyde releasers at the Finnish Institute of Occupational Health from 2007 to 2020.

Formaldehyde is an important contact sensitizer. Formaldehyde releasing substances induce positive reactions in formaldehyde-allergic patients, but there are also reactions independent of formaldehyde allergy. In an earlier study, stronger formaldehyde reactions led to more positive reactions to quaternium-15. To analyze patterns of positive patch test reactions to formaldehyde and different formaldehyde releasers. Patch test files of 1497 patients investigated during the period November 2007-August 2020 were retrospectively reviewed for positive reactions to formaldehyde and its releasers. During the study period, almost all (≥99.3%) patients were tested with a formaldehyde dilution series and six formaldehyde releasers. Ninety-three patients tested positive to formaldehyde; 80% of these had positive reactions to at least one formaldehyde releaser, most often benzylhemiformal. There were only nine independent contact allergies to formaldehyde releasers. There were only two reactions to 2-bromo-2-nitropropane-1,3-diol and they occurred in formaldehyde-negative patients. In patients with extreme (+++) reactions to formaldehyde, concomitant positive reactions to any of the other 11 investigated formaldehyde releasers were more common than in patients with milder formaldehyde reactions. Strong formaldehyde reactions were associated with positive reactions to formaldehyde releasers.

Photochemical Reactivities and Photodynamic Effects of an Organorhodium Phthalocyanine

The light-triggered uncaging of bioactive molecules is attractive for a new type of photodynamic therapy (PDT) as it enables the tumor-selective cell attack in various mechanism of action. In particular, photochemical release of formaldehyde is promising as they exhibit cytotoxicity by the alkylation and crosslinking of biological tissues.[1] Meanwhile, methyl-cobalt porphyrinic compounds are known to give formaldehyde by the homolytic cleavage of a metal-carbon bond under visible light irradiation in the presence of molecular oxygen.[2] However, there has been no report on the photochemical formation of formaldehyde under irradiation of red light which shows high permeability toward biological tissues. In this study, the organometallic phthalocyanine complexes possessing a group 9 metal center were synthesized, and their photophysical properties, photochemical reactivities and photodynamic effects were investigated under red light irradiation.Through the screening of reaction conditions, the methyl-rhodium phthalocyanine complex (1) was found to give formaldehyde by irradiation of pulsed laser of red light in the presence of oxygen. The laser-power dependency on the conversion rate indicated that the metal-carbon bond of 1 is activated through the stepwise, two-photon excitation. In order to realize the photochemical formation of formaldehyde in biological environment, 1 was encapsulated into a liposome of 1,2-Dipalmitoyl-sn-glycero-3-phosphorylcholine (DPPC). By irradiation of red light, the liposomal 1 released formaldehyde in water under air. Finally, the phototoxicity and cytotoxicity of liposomal 1 toward HeLa cells were investigated. The HeLa cells treated by liposomal 1 were successfully killed by light irradiation, indicating that 1 exhibits the photodynamic effect.

A methodological approach for quantifying aerial formaldehyde released by some hair treatments-modeling a hair-salon environment

ABSTRACT Formaldehyde is a well-known toxic agent, therefore having a highly regulated status. Despite, some cosmetic firms recently introduced high and illegal concentrations of formaldehyde in hair treatments for increasing straightening and long-lasting performances. The objective of this study was to assess how and to which extent, these products may disperse formaldehyde in the environment of a hair salon, possibly exposing the consumer and the hair professional technician to hazardous airborne amounts of formaldehyde. A laboratory room was equipped with three air pumps located at three locations: close to the heads of a mannequin, nearby the hair technician and the whole volume of the room. Pumps were connected to cartridges apt at trapping airborne formaldehyde. The latter was further quantified through an HPLC procedure. As compared to hair treatments free from formaldehyde that do not modify the airborne formaldehyde levels, products with a high concentration of formaldehyde (1.7% and 9.3%) disperse this compound in the environment to a high and hazardous concentration, detrimental to both consumer and hair professional. The brushing procedure on the hair led to a much higher dispersion of airborne formaldehyde than the hair straightening/ironing technique. To conclude, the use of hair treatments that contain high and illegal amounts of formaldehyde creates a hazardous environment to all people present within a hair salon. Implications: This methodology adopted here might be used to evaluate during conception phase the level of Formaldehyde release and be used as part of safety data for the registration. However, the present work also strongly promotes the adoption of electronic detectors (commercially available) that continuously record the aerial concentration of Formaldehyde, when dealing with hair styling products that contain legal or illegal (> 0.2%w/w) content of Formaldehyde These detectors not only cover an adequate and realistic range of aerial Formaldehyde but can be used and transported at different locations of a given space. Such a cautious measure comes from common sense as it relates to the health status of consumers and operators present in a hair salon environment.

The European baseline series: Criteria for allergen inclusion (with reference to formaldehyde releasers).

Existing criteria for inclusion in the European baseline series are summarized. Additional criteria are developed to aid decision making where the current criteria do not yield an unequivocal result. These include a consideration of whether an allergen (hapten) is better placed in a special series and the frequency with which an allergen cross-reacts with existing markers in the baseline series.

Prevalence and trend of allergen sensitization in patients with nummular (discoid) eczema referred for patch testing: North American Contact Dermatitis Group data, 2001-2016.

Few studies have examined the relationship between nummular (discoid) eczema (NE) and allergic contact dermatitis (ACD). To examine trends, associations, and clinical relevance of ACD in patients with NE who were referred for patch testing. Retrospective analysis of 38 723 patients from the North American Contact Dermatitis Group. Overall, 748 patients (1.9%) were diagnosed with NE; 23.9% had a concomitant diagnosis of ACD. The prevalence of NE fluctuated over time between 2001 and 2016, with no overall change in prevalence in diagnosed NE. In multivariable logistic regression models, NE increased steadily with age and was associated with male sex and Asian and other race/ethnicity, and inversely associated with a history of atopic dermatitis (AD) and hay fever. Patients with NE had lower proportions of one or more positive allergic reactions and lower odds of a positive reaction in multiple individual allergens. The most commonly relevant allergens in patients with NE were formaldehyde 2.0% aq., methylisothiazolinone, quaternium 15, fragrance mix I, and propylene glycol. NE is a heterogeneous disorder with distinct subsets of lesional distributions and a profile of relevant allergens, especially formaldehyde and formaldehyde releasers. Nearly one in four patients with NE had ACD, supporting the role of patch testing in patients with NE.

Управление качеством, химической и радиационной безопасностью древесных плит, фанеры и мебели

The article analyzes the experience of development, implementation and certification of quality management systems at enterprises for the production of wood-based panels, plywood, furniture. The specifics of the implementation of the process approach in the QMS of enterprises, the experience of widespread use of methodological instructions (MI), standards of organizations (STO), guidelines (RD) are shown. Information is given on the demand for QMS certified by the Lessertika Center by foreign QMS certification bodies. A critical analysis of the state of chemical safety of wood-based panels and plywood, as well as the problems of implementation and implementation of TR CU 025/2012 «On the safety of furniture products» is given, directions for revising this TR CU are indicated. For the first time, special attention is paid to the analysis of the methods used by the RF for determining the release of formaldehyde from wood-based panels, plywood and furniture. The advantages and disadvantages of using three methods for assessing the emission of formaldehyde from wood materials and furniture are objectively considered, which will allow manufacturers, consumers of products and regulatory authorities to substantiate their requirements for the methods used to confirm the environmental friendliness of products. The experience of determining the content of radionuclides in wood materials and furniture is indicated.