13C NMR investigation of the reaction in water of UF resins with blocked emulsifiable isocyanates

被引:27
作者
Despres, A
Pizzi, A
Delmotte, L
机构
[1] Univ Nancy 1, ENSTIB, LERMAB, F-88000 Epinal, France
[2] ENSCMu, Mineral Mat Lab, F-68093 Mulhouse, France
关键词
blocked isocyanates; NMR; reactions; resins; structure; urea-formaldehyde; urethanes;
D O I
10.1002/app.22498
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
A solid state C-13 NMR Study of hardened networks obtained by the reaction of blocked and non-blocked isocyanates (pMDI) With urea-formaldehyde (UF) resins in water showed different results according to the temperature of the reaction. At high temperature, in water, both a nonblocked or an emulsifiable, blocked isocyanate, appear to crosslink with UF resins through the formation both of traditional methylene bridges Connecting Urea to urea and of urethane bridges. The latter have been confirmed by C-13 NMR to form in water by reaction of the isocyanate -N=C=O group with them hydroxymethyl groups of the UF resin. At ambient temperature, UF/pMDI resins where the pMDI is a emulsifiable blocked isocyanate, do not appear to form urethanes to any great extent but rather to crosslink through the usual UF resin Urea to urea methylene bridges. Even in this case, When urethane bridges appear to be absent, evidence of crosslinking in water through reaction of the isocyanate with the -NH2 and -NH-amide of the UF resin has not been observed. (c) 2005 Wiley Perodicals, Inc.
引用
收藏
页码:589 / 596
页数:8
相关论文
共 17 条
[1]  
ADCOCK T, 1999, P 3 EUR PAN PROD S L, P67
[2]   ISOCYANATE PHENOLICS WOOD ADHESIVES BY CATALYTIC ACCELERATION OF COPOLYMERIZATION [J].
BATUBENGA, DB ;
PIZZI, A ;
STEPHANOU, A ;
KRAUSE, R ;
CHEESMAN, P .
HOLZFORSCHUNG, 1995, 49 (01) :84-86
[3]  
*BIOR LAB, 1999, CHEMWINDOWS 6 5
[4]   THE HOT-PRESSING OF DRY-FORMED WOOD-BASED COMPOSITES .4. PREDICTED VARIATION OF MATTRESS MOISTURE-CONTENT WITH TIME [J].
BOLTON, AJ ;
HUMPHREY, PE ;
KAVVOURAS, PK .
HOLZFORSCHUNG, 1989, 43 (05) :345-349
[5]  
CHEUNG IS, 1994, J APPL POLYM SCI, V52, P1637
[6]  
HAIDER KW, 2000, TRAIL ISOCYANATE PHE, P85
[7]  
MARCINKO JJ, 2000, WOOD ADHESIVES 2000, P23
[8]  
Miller T. R., 2002, US patent, Patent No. [6,416,696, 6416696]
[9]   NONEMULSIFIABLE, WATER-BASED, MIXED DIISOCYANATE ADHESIVE SYSTEMS FOR EXTERIOR PLYWOOD .1. NOVEL REACTION-MECHANISMS AND THEIR CHEMICAL EVIDENCE [J].
PIZZI, A ;
WALTON, T .
HOLZFORSCHUNG, 1992, 46 (06) :541-547
[10]  
PIZZI A, 1993, HOLZFORSCHUNG, V47, P69