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Development of high efficiency nanofibrous air filter membrane by electrospinning process, to address the air pollution (both the particulate matter and the gaseous components) problem, which has become a major environmental concern.

By exploiting the advantage of active sites on soy protein isolate (SPI), the very high surface area of micro-pore rich activated carbon (AC) and the biocompatibility and biodegradable nature of polyvinyl alcohol (PVA). The authors have developed a SPI/AC/PVA hybrid membrane. Spun-bond nonwoven substrate was used as the support material to enhance the mechanical properties and also the filter handling properties. The properties of nanofibrous membrane including morphology, air permeability, filtration efficiency and formaldehyde absorption test were carried out as per standard test methods.

SPI-based membrane offers a great potential in air filtration/purification applications. Its potential to capture glancing pollutants at the molecular level is because of the presence of numerous functional groups on the soy protein surface, which enhances the adsorption of particulate matter and toxic gases, even bacteria and viruses to its surface.

The results are anticipated to provide a potential method to promote the development of a nanofibrous membrane, which can act as a high performance, dual function and eco-friendly air filter/purifier.

The purpose of the study was to prepare melamine-urea-formaldehyde (MUF) resin that would be resistant to boiling water and high temperature and exhibit low formaldehyde emission.

The authors prepared MUF resin with different F/(M + U) and changed the amount of melamine added, through the analysis of MUF resin properties to get the best reaction parameters, and used different amino acid cure systems including NH₄Cl cured the resin.

Resin’s heat resistance and water resistance are mainly determined by the amount of melamine added, and formaldehyde emission of the plywood can be changed by adjusting F/(M + U). The peak temperature of the curing agent-cured resin increases as compared with the self-curing resin. Stronger the acidity of curing agent, faster the viscosity increased in probation period and lower the bonding strength and heat resistance of the resin.

Melamine improves the heat resistance and water resistance of the resin. When the amount of melamine is more than a certain value, water resistance of the resin decreased.

MUF resin that is resistant to boiling water and exhibits low formaldehyde emission can be used in high temperature, high humidity and strict formaldehyde emission environment and can also be combined with other materials.

It was helpful to reduce the effect of formaldehyde emission on people’s health and environmental pollution and is also beneficial for the expansion of the application range of aldehyde resin.

The originality is twofold: the influence of the acid strength of curing agent on the bonding strength of the resin adhesive and the method for preparing high performance MUF resin by following the traditional process.

The paper deals with the mode of film formation from urea–formaldehyde and melamine–formaldehyde resins combined with alkyd resin based on castor oil‐modified alkyd. The properties of hardened coatings (such as hardness, chemical stability, and adhesion to substrate) were followed in dependence on the ratios of reaction components. An apparatus was built for measuring the formaldehyde emissions escaping from the solid coating films. The determination was performed by the pararosaniline method. The addition of imidazolidine in a concentration up to 10 per cent can reduce the emissions of formaldehyde escaping from the solid films to a considerable amount.

The purpose of this paper is to examine the effects of denaturised rice bran (RB) and route of its incorporation during synthesis of urea-formaldehyde adhesive, on the performance of the resulting adhesive, especially viscosity, free-formaldehyde (HCHO) and quality of the produced bagasse-based composites, in comparison with those produced from commercial urea formaldehyde (UF) and RB-added UF.

The experiments were carried out using different denaturised RB at different percentages (1-5 per cent) and pH’s (9-11 per cent). These denaturised RB were incorporated at the last synthesis stage of UF synthesis process. The assessment was carried out on both the viscosity and environmental safety of the adhesive system, as well as the quality of the manufactured bagasse-based composites, of the particleboards (static bending, internal bond (IB) strength and water resistance properties), in comparison to commercial UF and RB added to UF. The performance of the adhesive system was evidenced by the thermogravimetric analysis and differential scanning calorimetry analyses.

The results showed that maximum static bending [modulus of rupture (MOR) and modulus of elasticity (MOE)], IB strength and water resistance properties of the resulted wood product accompanied the incorporating 5 per cent of the denaturised RB (pH = 9.0), at the last synthesised stage of UF synthesis process. Where, this synthesis process provided adhesive with viscosity nearly approaching to commercial UF adhesive, and reduced the free-HCHO of adhesive and board by approximately 56 and 49 per cent, respectively. For mechanical and water resistance properties, it provided board with 24.5 MPa MOR, 3,029 MPa MOE, 0.64 MPa IB, 11 per cent swelling (SW) and 20.5 per cent absorption. These properties fulfil the requirements of high grade particleboards American National Standard Institute (ANSI) A208.1, especially with respect to static bending values and water swelling property.

Incorporating 5 per cent of pre-denaturised RB, at pH 9.0, in wet form, and in the last stage of synthesis UF, provided adhesive system with convenient viscosity together with lower free-HCHO and acceptable board properties, compared with that produced from commercial UF, or adding denaturised RB to already synthesised UF. For the mechanical (MOR, MOE and IB) and water resistance properties (SW per cent and absorption per cent) of the produced composite are complied the standard values of H-3 grade of particleboard.

Promising adhesive system is resulted from incorporating 5 per cent of pre-denaturised RB at pH 9.0, in wet form, during last stage of UF synthesis process.

Incorporating the RB by-product of oil production to commercial UF or during synthesis of UF will be benefit for saving the healthy of wood co-workers, and motivating the wood mill to export its wood products.

The article provides a potential simple way to solve the drawback of increasing the viscosity of UF, as a result of adding RB, via incorporating the RB during synthesis process. The viscosity of the synthesised RB-modified UF approaches RB-free UF, and consequently the adhesive system easily penetrates through agro-fibres, and provides good bonding behaviour and high performance wood product (both quality and environmental by minimising formaldehyde emission or toxic gasses during board formation).

The purpose of this paper is to describe the development of an eco‐friendly tannin‐phenol formaldehyde resin (PFT) applicable in the wood composite industry.

The bark of oak (Quercus castaneifolia) contains a large amount of condensed tannin. Condensed tannin, with a large amount of Catechol groups was considered for reducing the formaldehyde emission level on the adhesive system. Physical characteristics of synthesized PFT resin were evaluated.

For optimal extraction, three solvents were used in the extraction process. The results showed that a mixture of water‐methanol (1:1 v/v) as extracting solvent is the best solvent and yields about 14 per cent tannin based on dry weight of bark. For producing tannin phenol formaldehyde adhesive, 10 per cent, 20 per cent and 30 per cent (based on PF dry weight) of PF, substituted with natural extracted tannin. For evaluating PFT performance effects of percentage amount of substitution tannin content on the gel time, viscosity, pH, and density of adhesives were evaluated. Based on emission test (JIS A 1460‐2001) formaldehyde emission of PFT 10 per cent, 20 per cent and 30 per cent were 1.13, 1.12 and 0.4 mg/100 g, which is very low compared with tannin‐free PF.

Tannin‐PF adhesive compared to PF adhesive had lower PH, higher viscosity and shorter gel time.

The method developed provides a simple and excellent renewable resource “tannin” which can be used or partially substituted in phenol formaldehyde adhesive.

Results showed that replacing PF for tannin reduces modulus of rupture (MOR) and modulus of elasticity (MOE) slightly but has significant effects on IB, water absorption and thickness swelling.

In this paper sisal fibre (SF) was pretreated by alkali, KH-550, and steam explosion. Then sisal fibre/phenol formaldehyde (SF/PF) composites were prepared through compression molding. The effects of the sisal fibre addition mode and sisal/glass (SF/GF) hybrid phenol formaldehyde composites with glass/sisal weight ratio on mechanical properties, thermal properties, water absorption properties and electrically insulating properties were studied. Meanwhile, the effects of sisal treatments were also examined. Results indicate that polymerization-filling is a novel synthesizing method and KH-550 treatment is an ideal method for the modification of SF. The SF/PF composites made by the polymerization-filling method increased by 17.61%, 7.16% and 12.25% in impact strength, bending strength and bending modulus respectively compared with using the conventional physical blending method. SF/GF/PF composites showed higher mechanical properties when SF/GF was 1/1, and thermal properties improved with the addition of GF; sisal fibre and glass fibre exhibited positive hybrid effect in water absorption properties while negative hybrid effect in insulating properties. A study of fibre-matrix interaction and fracture behavior of the fractured surfaces of the composites was also made by scanning electron micrographs.

This study aims to prepare a low-formaldehyde and environmentally friendly glucose-lignin-based phenolic resin.

The authors directly used lignin to substitute formaldehyde to prepare lignin-based phenolic resin (LPF) with urea as formaldehyde absorbent. To improve the performance of the adhesive, the biobased glucose was introduced and the modified glucose-LPF (GLPF) was obtained.

The results showed that when the replacing amount of lignin to formaldehyde reached 15 Wt.%, the physical properties of the prepared LPF met the Chinese national standard, and the bonding strength increased by 21.9%, from 0.75 to 0.96 MPa, compared with PF. The addition of glucose boost the performance of wood adhesive, for example, the free phenol content of the obtained GLPF was significantly reduced by 79.11%, from 5.60% to 1.17%, the bonding strength (1.19 MPa) of GLPF increased by 19.3% in comparison to LPF and the curing temperature of GLPF decreased by 13.08%.

The low-formaldehyde and environmentally friendly GLPF has higher bonding strength and lower curing temperature, which is profitable to industrial application.

The prepared GLPF has lower free formaldehyde and formaldehyde emission, which is cost-effective and beneficial to human health.

The joint work of lignin and glucose provides the wood adhesive with increased bonding strength, decreased free phenol content and reduced curing temperature.

Cyclohexanone-formaldehyde resin (CFR) was in situ modified with olive pomace (OP) in the presence of sodium hydroxide. The purpose of this study is to produce eco-friendly OP modified cyclohexanone composite resins (OPCFCR) with a one-step method that has higher condensation reaction temperature than CFR. The water absorption properties, gloss value and cross-cut adhesion properties of the product were investigated.

Cyclohexanone, formalin (37% aqueous solution) and tannin were mixed and 20% aqueous NaOH solution was added to produce the resin. OP has environmentally friendly bio-based lignin, cellulose and phenolic compounds and the OP structure has been incorporated into the structure of the CFR resin during the in situ modification, such as resole resin and polysaccharide. The weights of pomace were used as 5% and 10% of the weight of cyclohexanone in cyclohexanone-formaldehyde composite resins, respectively.

There is an improvement in the properties of the OPCFCR produced from an agricultural waste that is very abundant in Gulf of Edremit region of Balikesir. The OPCFCRs were soluble in common organic solvents. The product OPCFCR has a dark red-brown color.

The reaction mixture must be stirred continuously. Subsequently, 37% formalin was added dropwise in total while refluxing. The amount of aqueous NaOH solution is limited as the formed resin may become insoluble in common organic solvents. At the end of the reaction, a water-insoluble resin is obtained.

This study provides the application of ketonic resins. The OPCFCR containing phenolic groups may also promote the adhesive strength of a coating.

These resins may be used for the preparation of adhesive. OP, with a large amount of catechol groups, was considered for reducing the formaldehyde emission level on the adhesive system.

OPCFCR has been synthesized in the presence of a base catalyst. Environmental and ecological concerns have increased the attention paid by chemical industry to renewable raw materials.

The purpose of this paper is to study the corrosion protective properties of modified urea and/or thiourea formaldehyde resins for steel surface.

Three butyl alcohol modified amino resins were laboratory prepared. The three modified resins were characterized using thermal gravimetric analysis and infrared; the solid content and refractive index of each were also measured.

The resins that contain both nitrogen and sulphur have excellent corrosion inhibitive activity compared with that containing nitrogen only.

The modified resins were based on urea formaldehyde resin, mixed urea and thiourea formaldehyde resin and thiourea formaldehyde resin, respectively.

The prepared resins were introduced in different coating formulations based on short‐oil alkyd resin, medium‐oil alkyd resin and plasticized chlorinated rubber. They were then tested and evaluated for corrosion protection of steel surfaces.

All the prepared resins show promising results for corrosion protection of steel surfaces.

Perfluoroheptyl methacrylate was copolymerized with acrylamide using different ratios of these monomers. The copolymers so obtained were methylolated with formaldehyde. The methylolated copolymers were used as multi‐purpose finishing agents for cotton. They impart oil and water repellence. Attachment of the methylolated copolymer to cotton is presumed to involve chemical bonds via reaction of the methylol groups of the copolymer and the hydroxy groups of cotton cellulose. This was evidenced by the wash‐fastness properties; no significant differences were noted in the oil/water repellence of cotton fabric treated with the copolymers in question.