New melamine resins. I. Synthesis of reactive solvents for melamine

Wirpsza, Zygmunt; Kucharski, Mieczysław; Lubczak, Jacek

doi:10.1002/(sici)1097-4628(19980207)67:6<1039::aid-app11>3.3.co;2-x

Cited by 13 publications

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“…Therefore the synthetic procedure leading to carbazole-incorporated novolac and resol was modified by addition of HMA as a source of formaldehyde and good solvent for otherwise insoluble carbazole. 20,28 .…”

Section: Resultsmentioning

confidence: 99%

“…Thus HMA was quantitatively characterized and used as such to obtain novolac and resol resins with slightly prolonged reaction time (100-105 ∘ C for 2.5 h for novolac and 75 ∘ C for 4 h for resol) in comparison with previously described protocol. 20,21 The starting amounts used to obtain novolac were 2.54 mol of phenol per 100 g of HMA, and 1.80 mol of phenol per 100 g of HMA to obtain resol. Further, the series of syntheses were performed by addition of carbazole into phenol and HMA.…”

Section: Resultsmentioning

confidence: 99%

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Thermally resistant carbazole-modified phenol-formaldehyde resins

Lubczak

2015

Polym. Int.

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Phenol–formaldehyde resins were modified with carbazole in order to improve their thermal resistance. Attempts to incorporate carbazole rings into novolac and resol resins were made using three methods: (1) the addition of N‐(hydroxymethyl)carbazole (HMC) into a phenol–formaldehyde mixture, (2) the addition of carbazole into a phenol–hydroxymethyl derivative of acetone mixture, where the hydroxymethyl derivative of acetone was used as formaldehyde donor, and (3) by prolonging the time of high‐temperature reaction between phenol, carbazole and formaldehyde. The temperature and time of reaction were critical for incorporation of carbazole, which successfully led to highly temperature‐resistant carbazole‐modified novolacs for the latter procedure. When carbazole was incorporated into novolac structure at a level of 8 mol%, the thermal resistance increased by 118 °C measured as 5% mass loss temperature. Other procedures led to solids containing carbazole or HMC as physical admixtures. The obtained composites revealed variable thermal resistance effects; the carbazole‐modified resol containing 9 mol% of carbazole showed 47 °C increase of thermal resistance in comparison with non‐modified resol, measured as 5% mass loss temperature. © 2015 Society of Chemical Industry

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Thermally resistant carbazole-modified phenol-formaldehyde resins

Lubczak

2015

Polym. Int.

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“…Equations (9)(10)(11)(12)(13)(14) are equivalent to eqs. (1)(2)(3)(4)(5)(6), except for the fact that any M-based molecule is characterized by P A 0 ;A 1 ;A 2 ;M 0 ;E 0 ; where A 0 , A 1 , and A 2 are the number of primary, secondary, and tertiary amines [ANH 2 , ANHCH 2 OH, and AN(CH 2 OH) 2 , respectively]; and M 0 and E 0 are the number of unsubstituted methylene and ether bridges (ANHCH 2 NHA and ANHCH 2 OCH 2 NHA, respectively). Figure 4 illustrates a hypothetical isomer of P 4,1,1,2,1 .…”

Section: Mathematical Modelmentioning

confidence: 99%

Methylolation of melamine with incipient condensation. II. Mathematical modeling

Nicolau

Estenoz

Meira

2009

J of Applied Polymer Sci

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A novel mathematical model is presented for the reaction between melamine (M) and formaldehyde (F) at pH ¼ 9.0 and at temperatures between 38 and 90 C. It is based on a kinetic scheme that includes reversible methylolations, irreversible formation of (unsubstituted) methylene bridges, reversible formation of (unsubstituted) ether bridges, instantaneous dissolution of M, and instantaneous equilibrium for the hydration/dehydration of F. The model predicts the distributions of molecular weights and functionalities of the evolving MF resin. Arrhenius expressions were adjusted for the seven kinetic constants on the basis of measurements reported in the first part of this series. Even though the final products contain thousands of different molecular species, 21 of them constitute more than 90% of the total weights. During the initial period with negligible condensation, the undissolved M distorts the distributions of molecular weights and functionalities; but the reversibility of methylolations corrects for such distortion prior to the effective start of condensation.

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“…The reactive solvents, for example, solvents based on formaldehyde and cyclohexanone, not only dissolve melamine physically but also react with melamine, building into its structure. [2][3][4][5][6] The resulting viscous resinlike solution can be used as a binder in melamine-formaldehyde-cyclohexanone (Mel-F-CH) molding compositions and filled compression-molding compounds.…”

Section: Introductionmentioning

confidence: 99%

New melamine–formaldehyde–ketone resins. VI. Preparation of filled molding compositions and compression‐molding materials from reactive solvents based on cyclohexanone

Głowacz-Czerwonka

Kucharski

2010

J of Applied Polymer Sci

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ABSTRACT:The conditions and a method of preparing new molding compositions and filled compression-molding materials from melamine-formaldehyde-cyclohexanone resins are described. The resins were obtained from melamine solutions in a reactive solvent prepared by the reaction of 1 mol of cyclohexanone with 7 mol of formaldehyde. The fillers were wood powder and sulfite cellulose. The thermal properties of the samples prepared from the compositions were studied with dynamic thermal analysis, thermogravimetry, and differential scanning calorimetry analysis. Selected mechanical properties [Brinell hardness, unnotched impact strength (Charpy method), and bending strength] of the cured resins were also measured.

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New melamine resins. I. Synthesis of reactive solvents for melamine

Cited by 13 publications

References 0 publications

Thermally resistant carbazole-modified phenol-formaldehyde resins

Thermally resistant carbazole-modified phenol-formaldehyde resins

Methylolation of melamine with incipient condensation. II. Mathematical modeling

New melamine–formaldehyde–ketone resins. VI. Preparation of filled molding compositions and compression‐molding materials from reactive solvents based on cyclohexanone

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