Thermal stability of melamine formal‐dehyde resins

Manley, T.R.; Higgs, Denis

doi:10.1002/polc.5070420337

Cited by 20 publications

(15 citation statements)

References 5 publications

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“…The first stage associated with the moderate weight loss in the temperature range of 25−150 °C (region I) is attributed to the loss of water from the condensation reaction that increased the cross-linking extent of melamine-formaldehyde-resorcinol resin. 50 It was deduced that the first exothermic peak in the temperature range of 60−150 °C was ascribed to the formation of branched-type methylene bridges, which were cross-linked between the free polymer chains through polycondensation reaction. In the second stage, the precursor exhibited a rapid weight loss when the temperature increased from 150 to 300 °C (region II), due to the pyrolysis of methylene cross-links in resin and the organic species in EDTMPA-Co. 50,51 The third stage shows a gradual mass decrease in the temperature range of 300−875 °C (region III), along with a broad exothermic peak centered at 450 °C.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Molecular-Level Synthesis of Cobalt Phosphide Nanocrystals Confined in Highly Nitrogen-Doped Mesoporous Carbon Electrocatalyst for Highly Efficient Dye-Sensitized Solar Cells

Chen

Shao

Dong

et al. 2020

ACS Sustainable Chem. Eng.

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Developing an efficient synthetic approach for the accurate synthesis of nonprecious metal counter electrode (CE) electrocatalysts with superior catalytic activity and electrochemical stability is critically important for the commercial application of dye-sensitized solar cells (DSSCs). In this study, a new molecular-level synthetic strategy was innovatively developed by copolymerization of melamine and resorcinol with formaldehyde under specific pH conditions and their hydrothermal cooperative assembly with organic–inorganic cobalt phosphate and F127 to construct the high-molecular-weight EDTMPA-Co/melamine-formaldehyde-resorcinol resin/F127 copolymer with good thermal stability and compositional homogeneity. The subsequent carbothermal reduction of EDTMPA-Co using melamine-formaldehyde-resorcinol resin as carbon–nitrogen cosources and F127 as a soft template contributed to the accurate synthesis of uniformly dispersed cobalt phosphide nanoparticles incorporated in a highly nitrogen-doped mesoporous carbon (CoP/NMC) catalyst for the first time. It was found that the abundant mesopores, high-nitrogen-content conductive carbon walls (12.8 atom %), and numerous exposed CoP nanoparticles were creatively formed in the resultant CoP/NMC hybrid, which greatly accelerated the electrolyte/electron transportation and supplied sufficient ion-accessible electrocatalytic nanoactive sites for catalysis. When applied as a CE catalyst, the CoP/NMC hybrid revealed a strong synergistic effect in adsorption and catalytic reduction of triiodide ions, and the CoP/NMC reached a low charge transfer resistance (R ct) of 1.35 Ω. As a consequence, the CoP/NMC CE assembled DSSC delivered a high photo-to-electricity conversion efficiency (η) of 8.53% and exceptional long-term electrochemical stability with a remnant efficiency of 7.80% after 200 h of illumination, outperforming the state-of-the-art Pt. The catalytic mechanism of CoP/NMC CE toward triiodide reduction was studied by density functional theory calculations, which revealed that the relative energy for breaking the I–I bond was significantly improved by chemisorption-induced formation of Co–I covalent bonds between the triiodide intermediate and Coσ+ atoms in the exposed CoP nanoactive sites, and the electrocatalytic reduction of I2* to I–* was substantially facilitated.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Molecular-Level Synthesis of Cobalt Phosphide Nanocrystals Confined in Highly Nitrogen-Doped Mesoporous Carbon Electrocatalyst for Highly Efficient Dye-Sensitized Solar Cells

Chen

Shao

Dong

et al. 2020

ACS Sustainable Chem. Eng.

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“…The weight loss in this step is 14.3 %. The main weight loss of 29 % at the fourth step observed in the temperature range of 623-683 K is attributed to the breakdown of methylene bridges [25]. The last weight loss of 22.8 % occurring in the temperature range of 683-973 K is assigned to the thermal decomposition of triazine ring [26].…”

Section: Structure and Thermal Properties Of Mf Resinmentioning

confidence: 98%

“…The first step of weight loss (5.2 %) in the 303-423 K range is due to the evaporation of absorbed water. The second step occurring between 423 and 673 K can be attributed to the breakdown of methylene or ether bridges [25]. The third weight loss at the temperatures higher than 673 K is ascribed to the thermal degradation of the triazine ring [28].…”

Section: Structure and Thermal Properties Of Mf Resinmentioning

confidence: 99%

Development of Heterogeneous Alkali Methoxide Catalyst from Fly Ash and Limestone

Widayat¹,

Christwardana²,

Syaiful³

et al. 2020

ChChT

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This study is aimed to use fly ash and limestone as raw materials for preparing alkali methoxide heterogeneous catalysts for transesterification of palm oil into biodiesel. The heterogeneous catalyst was synthesized from fly ash and limestone through wet and dry methods and calcined within 1073–1273 K. X-ray diffraction and scanning electron microscopy analyses indicated the well-dispersed presence of the Ca(OCH3)2 crystal over the fly ash and limestone framework, which was mixed using wet method and calcined at 1073 K (W-800). Results showed that W-800 exhibited larger surface area and more uniform active sites than the other catalysts. About 88.6 % of biodiesel was produced from commercial palm oil with W-800 as the catalyst. The product possesses physicochemical characteristics, such as density, kinematic viscosity and free fatty acid content, which satisfy the international biodiesel standard. The catalyst was used for biodiesel production for four cycles, and the biodiesel yield was maintained up to 91.87 % from the initial value.

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“…10). Quite some early work has been performed and published on the thermal degradation [36][37][38][39] and hydrolysis [32] of melamin-formaldehyde resins, but rather little is published on the stability of this resin type when outdoor weathering conditions are applied [3,31]. The melamine units in a melamine-formaldehyde resin (MF resin) are connected via methylene-ether bridges (see structure (1) in Fig.…”

Section: Sem/edx Of the Surfacesmentioning

confidence: 99%

Visualisation and characterisation of ageing induced changes of polymeric surfaces by spectroscopic imaging methods

Eder¹,

Spoljaric-Lukacic²,

Chernev

2012

Anal Bioanal Chem

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A polymeric resin material was chosen as the model system to visualise the ageing-induced chemical surface changes with molecular spectroscopic imaging techniques and correlate these results to physical properties such as colour changes. The influence of light radiation, temperature and humidity on the polymeric surfaces was analysed by means of attenuated total reflection infrared imaging, Raman imaging spectroscopy and scanning electron microscopy. Samples were analysed before, during and after the weathering/ageing tests. From these combined data, the mechanisms for the damaging of the resin surface under the various environmental conditions (as applied in the accelerated ageing tests) were deduced. Photo-oxidative decay of the resin leading to a degradation of the uppermost surface layers as well as hydrolysis of the aged surface was identified. The combination of the spectral and spatial data as obtained from spectroscopic imaging with the morphological and elemental information of scanning electron microscopic mapping experiments turned out to be highly advantageous for the elucidation of ageing processes. A correlation between the molecular spectroscopic data and the results from the macroscopic colour difference measurements was found.

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Thermal stability of melamine formal‐dehyde resins

Cited by 20 publications

References 5 publications

Molecular-Level Synthesis of Cobalt Phosphide Nanocrystals Confined in Highly Nitrogen-Doped Mesoporous Carbon Electrocatalyst for Highly Efficient Dye-Sensitized Solar Cells

Molecular-Level Synthesis of Cobalt Phosphide Nanocrystals Confined in Highly Nitrogen-Doped Mesoporous Carbon Electrocatalyst for Highly Efficient Dye-Sensitized Solar Cells

Development of Heterogeneous Alkali Methoxide Catalyst from Fly Ash and Limestone

Visualisation and characterisation of ageing induced changes of polymeric surfaces by spectroscopic imaging methods

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