Formaldehyde Release Research Articles

Cosmetic Preservatives as Therapeutic Corneal and Scleral Tissue Cross-Linking Agents

Previously, aliphatic β-nitroalcohols (BNAs) have been studied as a means to chemically induce tissue cross-linking (TXL) of cornea and sclera. There are a number of related and possibly more potent agents, known as formaldehyde releasers (FARs), that are in commercial use as preservatives in cosmetics and other personal care products. The present study was undertaken in order to screen such compounds for potential clinical utility as therapeutic TXL agents. A chemical registry of 62 FARs was created from a literature review and included characteristics relevant to TXL such as molecular weight, carcinogenicity/mutagenicity, toxicity, hydrophobicity, and commercial availability. From this registry, five compounds [diazolidinyl urea (DAU), imidazolidinyl urea (IMU), sodium hydroxymethylglycinate (SMG), DMDM hydantoin (DMDM), 5-Ethyl-3,7-dioxa-1-azabicyclo [3.3.0] octane (OCT)] were selected for efficacy screening using two independent systems, an ex vivo rabbit corneal cross-linking simulation setup and incubation of cut scleral tissue pieces. Treatments were conducted at pH 7.4 or 8.5 for 30 minutes. Efficacy was evaluated using thermal denaturation temperature (Tm), and cell toxicity was studied using the trypan blue exclusion method. Cross-linking effects in the five selected FARs were pH and concentration dependent. Overall, the Tm shifts were in agreement with both cornea and sclera. By comparison with BNAs previously reported upon, the FARs identified in this study were significantly more potent but with similar or better cytotoxicity. The FARs, a class of compounds well known to the cosmetic industry, may have utility as therapeutic TXL agents. The compounds studied thus far show promise and will be further tested.

Formaldehyde may be found in cosmetic products even when unlabelled.

Concomitant contact allergy to formaldehyde and formaldehyde-releasers remains common among patients with allergic contact dermatitis. Concentration of free formaldehyde in cosmetic products within allowed limits have been shown to induce dermatitis from short-term use on normal skin.The aim of this study was to investigate the formaldehyde content of cosmetic products made in Lithuania. 42 samples were analysed with the chromotropic acid (CA) method for semi-quantitative formaldehyde determination. These included 24 leave-on (e.g., creams, lotions) and 18 rinse-off (e.g., shampoos, soaps) products. Formaldehyde releasers were declared on the labels of 10 products. No formaldehyde releaser was declared on the label of the only face cream investigated, but levels of free formaldehyde with the CA method was >40 mg/ml and when analysed with a high-performance liquid chromatographic method – 532 ppm. According to the EU Cosmetic directive, if the concentration of formaldehyde is above 0.05% a cosmetic product must be labelled “contains formaldehyde“. It could be difficult for patients allergic to formaldehyde to avoid contact with products containing it as its presence cannot be determined from the ingredient labelling with certainty. The CA method is a simple and reliable method for detecting formaldehyde presence in cosmetic products.

Impacts of Limestone Particle Size on the Performance of Flexible Wood Fiber Composite Floor

Sustainable wood floor (WFF), produced from natural plants, is a sort of novel green and ecofriendly composite floor, which has been attracting more and more attention in the world. WFF also gives a solution of utilizations of agricultural wastes, such as bamboo mats and hemp hurd. The additive limestone powder plays key role in the performance of flexible bamboo composite floor, so, in this paper, the effects of limestone size and size distributions were investigated. The best particle size distributions of limestone are 25 wt% of 48 μm, 25 wt% of 106 μm, and 50 wt% of 160 μm. The as-obtained WFF has good elasticity, good affinity, and strong comfortableness as well as free formaldehyde release.

A review of the effects of formaldehyde release from endodontic materials.

Formaldehyde is present in most living cells and the environment. In dentistry, patients may be exposed to formaldehyde through the use of several endodontic materials (e.g. AH 26) and during formocresol pulpotomies. This review outlines how the human body reacts to formaldehyde exposure, how recent data has relooked at the issue of carcinogenicity and leukaemia associated with formaldehyde, and whether it is possible to quantify the amount of formaldehyde produced by endodontic cements. The review analyses the way formaldehyde is produced from epoxy resins and addresses the question of whether the amount of formaldehyde from endodontic cements is large enough to override the body's ability to deal with its own endogenous levels of formaldehyde and should the amount of formaldehyde produced be a concern.

Study on properties of cotton fabric incorporated with diammonium phosphate flame retardant through cyclodextrin and 1,2,3,4-butane tetracarboxylic acid binding system

The chemical and physical structure of cyclodextrin makes it attractive for use in flame retardant finishing for improving the functional properties and durability of the finished fabric. The suitability of cyclodextrins for grafting using viable techniques that could be reproduced was studied. The flame retardant diammonium phosphate was applied on cyclodextrin-grafted cotton fabric and grafted cum bonded with 1,2,3,4-butane tetracarboxylic acid fabric. The modified monochlorotriazinyl-β-cyclodextrin gives more percentage of grafting (2.7%) under normal processing conditions used for cotton fabric. The effect of treatments like cyclodextrin grafting and 1,2,3,4-butane tetracarboxylic acid treatment on grafted fabric were analysed for diammonium phosphate flame retardant finishing. The whiteness and loss of strength caused by the cyclodextrin grafting was within acceptable limits and the hand value alteration was very less. The flammability behaviour and durability after 1, 5, 10, 20 and 40 washing cycles were determined. The results reveal that the flame retardant property of cyclodextrin treatment enhances the durability of the fabric from non-durable to semi-durable, whereas the diammonium phosphate treatment on 1,2,3,4-butane tetracarboxylic acid/cyclodextrin-grafted fabric changes the flame retardant from non-durable to durable. The evolution of gases during the burning of untreated and treated samples was analysed and the results show that the cyclodextrin-grafted fabric masks the evolving gases to some extent during burning and also that there was less release of formaldehyde in grafted samples compared with ungrafted diammonium phosphate finished sample.

Improving urea formaldehyde resin properties by glyoxalated soda bagasse lignin

The aim of this research was a reduction of formaldehyde emission and the improvement of the water resistance of urea formaldehyde (UF) resins by incorporating glyoxalated soda bagasse lignin. For this purpose, various contents of unmodified and glyoxalated lignins (10, 15 and 20 %) were added at pH = 7 instead of second urea during the UF resin synthesis. The properties of the resins as well as water absorption, shear strength, and formaldehyde emission of plywood panels made with these adhesives were measured. Among all the resins synthesized, the resin yielding the best results (based on formaldehyde emission and gelation time as well as water absorption, mechanical strength, and formaldehyde content of the associated panels) was selected, and its properties were further analyzed by Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectrometry (FTIR), and X-ray Diffractometry (XRD). The lignin based resins yielded good shear strength of the plywood panels, passing comfortably relevant international standard specifications; the panels also showed lower formaldehyde emission and water absorption when compared to commercial UF adhesives. Based on these findings, it was attempted to improve the performance of soda bagasse lignin in UF resins by glyoxalation. The UF resin containing 15 % glyoxalated lignin (GLUF15) still exhibited less water absorption and formaldehyde release without significant differences in shear strength and physicochemical properties compared to the UF resin control. DSC analysis indicated that in comparison to UF resin the curing process of GLUF resin shifted to lower temperatures. According to the FTIR spectra, by addition of lignin the proportion of C–N bond in methylene linkages decreases when urea is partly replaced by lignin or glyoxalated lignin. XRD analysis indicated that the crystallinity of the UF resins decreased with addition of glyoxalated lignin.

Formaldehyde Release from Medium Density Fiberboard in Simulated Landfills for Recycling

Formaldehyde Release from Medium Density Fiberboard in Simulated Landfills for Recycling

Preservatives in cosmetics in the Israeli market conform well to the EU legislation.

Preservatives are important and frequent skin sensitizers, found in a wide range of products for personal and occupational use. According to the European legislation, some cosmetic ingredients are restricted in terms of quantity and a detailed list of ingredients must be present on the product or packaging. To examine the use of preservatives in common cosmetics on the Israeli market. Sixty different Israeli brand cosmetics, including shampoos, liquid soaps, body creams and hand creams were randomly selected. Ingredient labels were examined. The products were investigated by the chromotropic acid method for release of formaldehyde and by high performance liquid chromatography for the presence of formaldehyde, DMDM hydantoin and methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) and MI content. All products but one contained a detailed list of ingredients printed on the package. According to labelling, the most prevalent preservatives in Israeli shampoos and liquid soaps were DMDM hydantoin and MCI/MI. Hand creams and body creams contained mainly parabens but also iodopropynyl butylcarbamate, phenoxyethanol and DMDM hydantoin. Formaldehyde in doses from 4 to 429 ppm, and DMDM hydantoin were detected in 38 and 16 (63% and 27%) of the products, respectively. MCI/MI was detected in 11 (18%) of the products, with highest prevalence in rinse- off products (55%). Excluding one hand cream which measured 106 ppm MI, the amount of formaldehyde, DMDM hydantoin, MCI/MI and MI was within the allowed concentrations by the European directive in all cases. In Israel, adaptation of the European directive prevails, as shown by the measurements we performed on randomly selected products.

Formaldehyde emission in wood based panels: effect of curing reactions

The influence of hexamine formed as byproduct during the UF cure was ignored in the past. However, with the increasing interest on low formaldehyde emission boards, this issue has become more pertinent. Formaldehyde release from hexamine degradation is extensive and could limit the success of the development of low formaldehyde emission adhesives if the conventional latent catalysts remain in use.In this study, formaldehyde released from recycled wood, hexamine and cured UF resin was assessed. Citric and oxalic acid, in solid form, were used as catalysts for UF resin in the production of particleboard. Mats with solid acids are less susceptible to resin pre-cure than with a latent catalyst. However, they can have higher formaldehyde emissions than latent catalyst. When both catalysts were used, combined with an ultra-low formaldehyde to urea molar ratio resin the internal bond was improved and formaldehyde content was below 4 mg per 100 g of oven dry board.

Developing a new method of measuring formaldehyde emissions from wood based panels

A new and fast system for determining formaldehyde (HCHO) release of wood based panels (WBPs) for use in manufacturer’s labs was developed. For sample preparation, solid phase microextraction (SPME) with a derivatisation step was used. The analytical system consists of a gas chromatographic column (GC) coupled to a high field asymmetric waveform ion mobility spectrometer (FAIMS). The emitted HCHO is determined in gaseous form, i.e. without trapping it in water. The system runs quasi-continuously with a cycle time of 20 min. This paper explains the basic functioning, and presents first results from a field trial.

키토산 겔을 이용한 포름알데하이드 차폐 시트 개발

Sick-building syndrome occurs when indoor air is polluted with harmful volatile organic compounds such as formaldehyde which are contained in furniture or new building materials. In this study, formaldehyde-shielding chitosangel sheet was developed and its performance was evaluated. Chitosan and agar were dissolved in acetic acid solution. The optimal concentrations of chitosan, acetic acid and agar were 3, 3, and 2.5 %(w/w). Formaldehyde was spreaded on gypsum board and then wall paper was attached on it by using glue. When chitosan-gel sheet was attached on this control board, the amount of formaldehyde released from the board was decreased by 63% than in control board. On the other hand, decrease in formaldehyde releasing was only 32% when liquid solution of chitosan was spreaded on the control board. This result clearly indicates that chitosan-gel sheet removes formaldehyde more effectively than liqud solution of chitosan. Furthermore, this type of sheet is more applicable to new building than spraying type.

Manufacture and Properties of Environmental-Friendly Bagasse Particleboard with Low Resin Content

Environmental-friendly wood-based panels with low resin content were developed by adding a small amount of phenol formaldehyde (PF) resin and water-repellent paraffin to effectively control the release of free formaldehyde and thickness swelling of the boards. This research was designed to investigate the relations between the various manufacturing conditions and product properties, the effects of board desity, resin content and paraffin content on modulus of elasticity, modulus of rupture, internal bond strength and thickness swelling of the boards were demonstrated. Finally we reach a conclusion: under the pressing pressure of 5MPa, pressing temperature 180°C, pressing time 7min, resin content 3% and paraffin content 1.5%, the panel with a density of 0.7 g/cm3 can meet the national standard GB/T 4897.2-2003—for general purpose particleboards used in dry conditions. So it is possible to develop the environmental-friendly wood-based panel with low formaldehyde emission.

Determination of formaldehyde release from wood-based panels using SPME-GC-FAIMS

Several standardized methods exist to determine formaldehyde (HCHO) release from wood-based panels (WBPs). These methods were developed decades ago to be used in manufacturers laboratories to provide a mean of production control. They are robust and take several hours to yield results. Modern WBP panel production, however, is a continuous process. Therefore the established methods are too time-consuming for process control and process optimization with respect to HCHO release. Moreover, there is a strong trend of lowering the regulatory HCHO emission limits. Thus, there is a need for a comparatively fast and precise method which is suitable for the use on-site in a WBP manufacturers laboratory. In this work, an optimization of the solid phase micro extraction gas chromatography high field asymmetric waveform ion mobility spectrometry (SPME-GC-FAIMS) method is presented with respect to GC-FAIMS settings and the calibration procedure. It is also shown that, in addition to WBP block samples, also particles can be used for the measurement. The industrial applicability of SPME-GC-FAIMS system was demonstrated by testing the HCHO release of freshly produced WBPs on-site in the manufacturers laboratory.

Методы испытаний на токсичность древесно-стружечных плит и эффективные акцепторы формальдегида

There are many methods for the determination of formaldehyde from particleboard, but the main ones are two of them - the chamber and perforating ones. Chamber method allows simulating the conditions of use of plates, but it is longer than the express method or perforating method. The paper further elaborates chamber method. To effectively reduce the release of formaldehyde from particleboard chemicals (formaldehyde scaven-gers) are most useful, which interact with formaldehyde during hot pressing of boards. Such materials are sodium pentachloro-phenolate, complexes sodium pentachloro-phenolate, complex chrome-cupric-boric com-pound, fluorosilicate ammonium.

Synthesis and application of a formaldehyde-free flame retardant for bamboo viscose fabric

A formaldehyde-free flame retardant (EFFR) for bamboo viscose fabric was synthesized by raw materials of silanol, phosphorus pentoxide, and diethanolamine. The flame retardant had the dual function of imparting fire resistance and softness to bamboo viscose fabric; moreover, it had no halogen and free formaldehyde, and wouldn’t release formaldehyde during processing and end-use. The experimental results about choice of cross-linker stated that the cross-linker played a significant role in decreasing the flammability of bamboo viscose fabrics and improving durability of flame retardance. Cross-linkers of hexamethylol melamine (HMM) or dimethylol dihydroxy ethylene urea (DMDHEU) or water-soluble isocyanate-terminated (WIT) not only cross-linked with flame retardant and bamboo viscose cellulose to enhance durability of inflaming retarding, but also had nitrogen to improve nitrogen–phosphorus synergism. However, HMM and DMDHEU can release free formaldehyde. WIT is a kind of cross-linker which has no formaldehyde. The experimental results showed that the Limiting Oxygen Index (LOI) value of Vis-EFFR–WIT treated fabric was basically above 30%, and the handle of the finished fabric was ameliorated greatly because of its organosilyl constituent part, even after 30 laundry cycles, the fabric still had some flame retardancy and soft feeling.

Structural and biochemical study of Bacillus subtilis HmoB in complex with heme

Most bacteria have developed a hemoprotein degradation system to acquire iron from their hosts. Bacillus subtilis HmoB, a heme monooxygenase, is involved in the degradation of heme and subsequent release of iron. HmoB contains a C-terminal ABM domain, which is similar in sequence and structure to other heme monooxygenases. Heme degradation assay showed that highly conserved residues (N70, W128, and H138) near the heme-binding site were critical for activity of HmoB. However, HmoB was shown to be different from other bacterial heme oxygenases due to its longer N-terminal region and formation of a biological monomer instead of a dimer. The degradation product of B. subtilis HmoB was identified as staphylobilin from mass spectrometric analysis of the product and release of formaldehyde during degradation reaction.

Effects of recovered wood on the formaldehyde release of particleboards

Abstract Three-layer polymeric diphenyl-methane-diisocyanate (pMDI)-bonded particleboards (PBs) were produced with different proportions of simulated recovered wood (rW) in the core layers (cLs) to assess the effect of rW on the formaldehyde (FA) release of PB. A pre-test was conducted on furniture and particle mixtures of rW to determine the range of expectable FA emission of rW. The FA content of the raw particle mixtures could be predicted from the contents of the individual raw material and did not change compared to the PB. FA content correlated strongly with PB-FA emission. It was possible to predict the maximum PB-FA contents, which should not be exceeded according to F**** and CARB 2 by linear regression models. At moderate and high total FA emission levels, the FA emission of the particle mixtures was approximately 60% higher than the emission of PB blocks. At low total FA level, the flask method and the gas analysis method exhibited different results with regard to the emissions from particles and their respective PBs.

Coupled exposure to ingredients of cosmetic products: II. Preservatives

The use of cosmetics exposes consumers to mixtures of ingredients, many of which are potential allergens. Many cosmetics contain one or several preservatives, some being important contact allergens. To examine the pattern of co-exposure to preservatives in different categories of cosmetics. A survey of products marketed in Germany, conducted in 2006-2009 by the Chemical and Veterinary Investigation Office in Karlsruhe, identified 4680 products categorizable according to Annex I to the Cosmetics Directive with information on the presence of preservatives. The occurrence and co-occurrence of preservatives were analysed and presented in tabular and graphical format. Thirty per cent of all products were not declared to contain any preservatives; for 8%, no INCI labelling was present. For the remainder, the number of preservatives used tended to be higher in leave-on than in rinse-off products. Most often, combinations of (up to all five) parabens were used (39% of all products). Combinations with phenoxyethanol were also frequent. Formaldehyde releasers were found in 8% of products overall. The pattern of co-exposure to preservatives in important categories of cosmetic products illustrates the 'cocktail' of allergens that may facilitate sensitization, although, conversely, the combination of preservatives allows individual use levels to be kept lower, thereby possibly reducing sensitization risk.

Assessment of lowering formaldehyde release of particleboards using urea as a scavenger by chamber, perforator and flask method

Addition of urea to a melamine modified urea formaldehyde resin in the surface and core layer reduces significantly the formaldehyde release of the particleboards bonded therewith. Under the used boundary conditions (long press time) urea addition seems to have no noticeable negative impact on the physical–mechanical properties of the boards. The reduction of formaldehyde release due to urea addition as a scavenger can be followed by measuring the emission in the chamber according to EN 717-1, the perforator method according to EN 120 and the flask method as described in EN 717-3. The results reveal that under the used conditions a good correlation exists between the emission in the chamber and the corrected perforator values (R2 = 0·865), as well as between the chamber value and the formaldehyde emission measured by the 3h-flask method (R2 = 0·792) according to EN 717-3, a slightly better correlation was found between the measured flask values after 24 h and the emission in the chamber (R2 = 0·869). The correlations seem to hold in the emission range between 0·06 and 0·016 ppm.

Cutaneous delayed-type hypersensitivity in patients with atopic dermatitis: Reactivity to topical preservatives

Patients with atopic dermatitis (AD) have chronic dry skin to which they frequently apply skin care products containing preservatives, and they are predisposed to developing cutaneous delayed-type hypersensitivity. We sought to compare the rates of positive patch test reactions to allergens on the North American Contact Dermatitis Group (NACDG) standard tray among patients with and without AD and to assess whether atopic patients in our database were more likely to patch test positive to preservatives. A total of 2453 patients underwent patch testing to the NACDG standard screening series. The incidence of positive patch test reaction among patients with AD (n = 342) and without AD (n = 2111) was assessed. Statistical analysis was done using a χ(2) test. Compared with nonatopic patients, patients with AD were statistically more likely to have positive patch tests. AD was associated with contact hypersensitivity to quaternium-15, imidazolidinyl urea, DMDM hydantoin, and 2-bromo-2-nitropropane-1,3-diol but not to parabens, formaldehyde, or diazolidinyl urea. Only patients suspected of having allergic contact dermatitis were tested. Our population was geographically limited to metropolitan Kansas City, MO, and metropolitan New York City, NY. Patients with AD should avoid the use of skin care products preserved with formaldehyde releasers.