1996 Fiscal Year Final Research Report Summary
COCONDENSATION OF MELAMINE AND UREA THROUGH FORMALDEHYDE
| Project/Area Number |
07456077
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
林産学
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| Research Institution | University of Tsukuba |
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Principal Investigator |
TOMITA Bunichiro University of Tsukuba, Institute of Agricultural and Forest Engineering, Professor, 農林工学系, 教授 (40012075)
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| Project Period (FY) |
1995 – 1996
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| Keywords | urea / melamine / formaldehyde / cocondensation / C-13 NMR / methylene linkage / dimethylene ether linkage / C-13 enriched formaldehyde |
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| Research Abstract |
The C-13 NMR spectra of urea-formaldehyde (UF) resins, melamine-formaldehyde (MF) resins and melamine-urea (MUF) cocondensed resins synthesized with various conditions were measured with a frequency of 75 MHz. It was investigated whether the occurrences of cocondensation between melamine and urea through the formation of methylene or dimethylene ether linkages can be identified or not. Several reactions using labeling method with C-13 enriched formaldehyde under neutral conditions were also analyzed to determine the driving force to introduce the cocondensation through the formation methylene or dimethylene ether linkage into melamine-urea resin system.
The signals due to carbons of methylene linkages of UF resins were clearly identified from those of MF resins. the signals due to carbons of cocondensed methylene linkage could be recognized separately from those due to UF and MF resins. The formation of cocondesed methylene linkages was mainly induced by the reaction of methylol groups of melamine and primary amino groups of urea residue, and that of cocondensed dimethylene ether linkages was apt to take place in the case of shortage primary amino groups urea residue. It was concluded that the effective introduction of cocondesed methylene linkages can be done either by reacting methylolmelamine with urea or methylolureas abundant in the primary amino groups, or by reacting methylol groups of urea with amino groups of melamine.
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