Phenol Melamine Research Articles

Effect of Boron Compounds on Properties of Chinese Fir Wood Treated with PMUF Resin

Plantation Chinese fir wood was modified by low molecular weight phenol melamine urea formaldehyde (PMUF) resin and boron compounds (BB) through a progressive gradual infiltration process. The results showed that the limiting oxygen index (LOI) values, density, dimensional stability and static flexural properties of the PMUF resin treated wood gradually improved with the increase of resin solid content. When boron compounds were additionally introduced into the PMUF resin, the density and the LOI values of the samples of compound modification increased, whereas the anti-swelling efficiency, the modulus of rupture and impact toughness decreased by more than 17.6%, 10.1% and 42.9%, respectively. It was demonstrated by X-ray diffraction and Fourier transform infrared spectroscopy that boron compounds could improve the crystallinity of resin modified samples and did not have a chemical reaction with resin or wood. Scanning electron microscope analysis indicated boron compounds made the microstructure of the resin polymers loose, influencing the mechanical properties and dimensional stability of resin modified wood.

Thermal degradation and fire performance of wood treated with PMUF resin and boron compounds

SummaryPlantation Chinese fir wood was modified by low molecular weight phenol melamine urea formaldehyde (PMUF) resin, boron compounds (BB), and the mixture of PMUF/BB (PMUF‐BB), followed by a curing step. The fire performance and thermal degradation of wood was measured by limiting oxygen index instrument, cone calorimeter, and simultaneous thermal analysis. The results showed that the limiting oxygen index increased to 50.7%, 43.5%, and 55.0% for BB, PMUF, and PMUF‐BB samples, respectively. The PMUF resin decreased the heat release rate of wood but increased the total heat release compared with the control samples. The thermal analysis results demonstrated that PMUF resin enhanced the thermal stability of wood, however, had little impact on the residual chars. Combinative treatment with boron compounds could substantially reduce the fire risk for PMUF‐modified wood, making them especially useful for application in public settings.

A microporous carbon derived from phenol–melamine–formaldehyde resin by K2CO3 activation for lithium ion batteries

A microporous carbon material with large surface area was prepared by carbonizing and activating of phenol–melamine–formaldehyde resin, using K2CO3 as activation reagent. The textural characteristics of the carbon materials were characterized by scanning electron microscope, X-ray diffraction, Raman spectra, Brunauer–Emmett–Teller, elemental analyses, respectively. Results showed that the surface area and pore diameter of the activated carbon were 1,610 m2 g−1 and less than 2 nm. Electrochemical lithium insertion properties were also investigated. At a current density of 100 mA g−1, the activated carbon showed an enormous first-discharge capacity of 2,610 mAh g−1 and the first charge capacity of 992 mAh g−1. From the second cycle, the coulombic efficiency went up rapidly to above 95 %. The results indicated it may be a promising candidate as an anode material for lithium secondary batteries.

Highly stable performance of supercapacitors using microporous carbon derived from phenol–melamine–formaldehyde resin

A series of microporous carbons were prepared by simple carbonization and activation of phenol–melamine–formaldehyde resin. The morphology, surface area, and elemental composition of the samples were investigated by scanning electron microscope, Brunauer–Emmett–Teller measurement, Raman spectra, and elemental analysis, respectively. Electrochemical characteristics were evaluated by cyclic voltammograms, galvanostatic charge/discharge, and electrochemical impedance spectroscopy measurements in 6.0 mol L−1 KOH. The microporous carbon activated by KOH presented a high specific capacitance of 202 F g−1 at a scan rate of 2 mV s−1. Furthermore, the KOH-activated microporous carbon electrode exhibited durable operation, the total loss of capacitance after 20,000 cycles is 2% at a current density of 500 mA g−1. The good electrochemical performance of the activated carbon was ascribed to well-developed micropores, high surface area, larger pore volume as well as oxygen groups.

Nanoporous nitrogen doped carbon modified graphene as electrocatalyst for oxygen reduction reaction

Nanoporous nitrogen doped carbon was used to modify the surfaces of graphene sheets by carbonizing a mixture of graphene oxide and phenol–melamine–formaldehyde (PMF) pre-polymer in the presence of a soft template (F127). The resulting graphene based composite sheets (G-PMFs) have a sandwich structure with one graphene layer and two nanoporous nitrogen-doped carbon layers. G-PMFs have large specific surface areas of 190 to 630 m2 g−1 and exhibited high electrocatalytic activity, good durability and high selectivity for the oxygen reduction reaction. The performance of the Zn–air fuel cell with a G-PMF anode was tested and found to be comparable to that of the Zn–air cell with a commercial Pt/C anode. Thus, these metal-free catalysts are promising for applications in practical fuel cells.

A novel activated carbon for supercapacitors

A novel activated carbon has been prepared by simple carbonization and activation of phenol–melamine–formaldehyde resin which is synthesized by the condensation polymerization method. The morphology, thermal stability, surface area, elemental composition and surface chemical composition of samples have been investigated by scanning electron microscope, thermogravimetry and differential thermal analysis, Brunauer–Emmett–Teller measurement, elemental analysis and X-ray photoelectron spectroscopy, respectively. Electrochemical properties have been studied by cyclic voltammograms, galvanostatic charge/discharge, and electrochemical impedance spectroscopy measurements in 6molL−1 potassium hydroxide. The activated carbon shows good capacitive behavior and the specific capacitance is up to 210Fg−1, which indicates that it may be a promising candidate for supercapacitors.

Kinetics study of thermal decomposition of epoxy resins containing flame retardant components

Hyperbranched polyphosphate ester (HPPE) and phenolic melamine (PM) were blended in different ratios with a commercial epoxy resin to obtain a series of flame retardant resins. The thermal decomposition mechanism of their cured products in air was studied by thermogravimetric analysis and in situ Fourier-transform infrared spectroscopy. The degradation behaviours of epoxy resins containing various flame retardant components were found to be greatly changed. The incorporation of phosphorus and nitrogen compounds improved the thermal stability at elevated temperature. The kinetics of thermal decomposition was evaluated by Kissinger method, Flynn–Wall–Ozawa method and Horowitz–Metzger method. The results showed that the activation energy at lower degree of the degradation decreased by the incorporation of flame retardant components, while increased at higher degree of the degradation.

Expansion behaviour and thermal degradation of tri(acryloyloxyethyl) phosphate/methacrylated phenolic melamine intumescent flame retardant system

Tri(acryloyloxyethyl) phosphate (TAEP) was blended with methacrylated phenolic melamine (MAPM) in different ratios to obtain a series of UV curable intumescent flame retardant resins. The cured TAEP/MAPM samples greatly expanded when burning. Their expansion behaviour and flame retardance of the cured resins were characterized by the volume ratio after and before combustion, and by limiting oxygen index. A distinct synergistic effect was found between TAEP and MAPM. TAEP–0.30MAPM sample showed the highest expansion degree (104) and the highest LOI value (41) among all resins. The degradation was monitored by thermogravimetric analysis and in-situ Fourier-transform infrared spectroscopy. A degradation mechanism is suggested in which the phosphate group in TAEP first degraded to form poly(phosphoric acid)s, which further catalysed the degradation of the material to form char with emission of nitrogen volatiles from MAPM, leading to the formation of expanding char. The morphologic structures of crusts of the formed chars were observed by scanning electron microscopy, demonstrating the synergistic effect between TAEP and MAPM.

Thermal degradation and flame retardancy of a novel methacrylated phenolic melamine used for UV curable flame retardant coatings

Methacrylated phenolic melamine (MAPM) was synthesized as a flame retardant multifunctional oligomer for UV curable systems, and characterized by FTIR, 1H NMR and elemental analysis. A series of formulations was prepared based on MAPM and a commercial UV curable epoxy acrylate EB600. Their thermal behaviours were investigated by thermogravimetric analysis, indicating that MAPM had no effect on the char formation of EB600. The flammability was monitored by the limiting oxygen index (LOI); the LOI value of EB600 increased from 21.5 for pure EB600 to 26.5 for the blend containing 50% MAPM addition. The “composite bar test” result showed that the vapour phase action flame retardant mechanism was the dominant mode for MAPM. The thermal degradation mechanism of MAPM was investigated by in situ FTIR, DP–MS and elemental analysis. The results showed that MAPM first degraded to form melamine at around 300 °C, which would further undergo condensation on heating with elimination of ammonia. Nitrogen underwent about 19% conversion to the residue and 81% had vapourized below 500 °C.

A phosphate-based epoxy resin for flame retardance: synthesis, characterization, and cure properties

A phosphorus-containing oligomer, bis(3-hydroxyphenyl) phenyl phosphate (BHPP), was synthesized through the reaction of phenyl dichlorophosphate and 1,3-dihydroxybenzene, and characterized by elemental analysis, Fourier transform IR spectroscopy, and 1H NMR and 31P NMR spectroscopy. Consequently, the phosphate-based epoxy resins with a phosphorus content of 1 and 2 wt % were prepared via the reaction of diglycidyl ether of bisphenol-A with BHPP and bisphenol-A, and were confirmed with Fourier transform IR spectroscopy and gel permeation chromatography. Phenolic melamine, Novolak, and dicyanodiamide were used as curing agents to prepare the thermoset resins with the control and the phosphate-based epoxy resins. Thermal properties and thermal degradation behavior of these thermoset resins were investigated by using differential scanning calorimetry and thermogravimetric analysis. The thermoset resins cured with phenolic melamine exhibited higher glass-transition temperatures than the other cured resins owing to the high rigidity of their molecular chain. Thermogravimetric analysis studies demonstrated that the decomposition temperatures of the thermoset resins cured with Novolak were higher than those of the others. A synergistic effect from the combination of the phosphate-based epoxy resin and the nitrogen-containing curing agent can result in a great improvement of the flame retardance for their thermoset resins.

Synthesis, characterization, and cure properties of phosphorus-containing epoxy resins for flame retardance

An organophosphorus compound, 10-(2,5-dihydroxyl phenyl)-9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DHPDOPO), was synthesized through the reaction of 9,10-dihydro-9-oxa-10-phosphaphnanthrene-10-oxide (DOPO) and p-benzoquinone, and characterized by elemental analysis, Fourier transform infrared spectrum (FTIR), and 1H-NMR and 31P-NMR spectroscopes. Consequently, the phosphorus-containing epoxy resins with phosphorus content of 1 and 2 wt.% were prepared via the reaction of diglycidyl ether of bisphenol-A with DHPDOPO and bisphenol-A, and confirmed with FTIR and gel permeation chromatography (GPC). Phenolic melamine, novolak, and dicyanodiamide (DICY) were used as curing agents to prepare the thermosetted resins with the control and the phosphorus-containing epoxy resins. Thermal properties and thermal degradation behaviors of these the thermosetted resins were investigated by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Phenolic melamine-cured resins exhibited higher glass transition temperatures than the other cured resins due to the high rigidity of their molecular chain. TGA studies demonstrated that the decomposition temperatures of the novolak-cured resins were higher than those of the others. A synergistic effect from the combination of the phosphorus-containing epoxy resin and the nitrogen-containing curing agent can result in a great improvement of the flame retardance for their thermosetted resins.