Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Fracture cleavage analysis of PVAc latex adhesives: Influence of phenolic additives

Fracture cleavage analysis of PVAc latex adhesives: Influence of phenolic additives Mode I fracture cleavage testing was conducted on wood bonded with poly(vinyl acetate-co-NMA) latex adhesive containing two types/degrees of cross-linking: (1) cross-linking through AlCl 3 catalysis of N -methylolacrylamide (NMA) comonomer; and (2) additional cross-linking using a phenol-formaldehyde resol additive, in addition to AlCl 3 catalysis. The formulation lacking the phenolic additive performed well under dry conditions; but it completely failed during testing as a result of accelerated weathering. In contrast, fortification with the phenolic additive provided durability against accelerated weathering. In an effort to understand the effects of accelerated weathering, parallel-plate dynamic mechanical analysis was applied to freestanding neat adhesive films and to wood-bonded films (composites). Accelerated weathering dramatically altered the viscoelastic response of films and composites that lacked the phenolic additive; weathering caused a second, broad and reversible relaxation near 100°C, which might be because of softening of the poly(vinyl alcohol) interfacial agent used during emulsion polymerization. In contrast, samples formulated with the phenolic additive only displayed the typical base-polymer glass transition. Correlation of the fracture testing and the rheological analysis suggests that the phenolic additive promotes adhesive durability by cross-linking the interparticle boundaries, where poly(vinyl alcohol) is believed to reside. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Holzforschung - International Journal of the Biology, Chemistry, Physics and Technology of Wood de Gruyter

Loading next page...
 
/lp/de-gruyter/fracture-cleavage-analysis-of-pvac-latex-adhesives-influence-of-SU8g6kgvng

References (9)

Publisher
de Gruyter
Copyright
©2006 by Walter de Gruyter Berlin New York
ISSN
0018-3830
eISSN
1437-434X
DOI
10.1515/HF.2006.050
Publisher site
See Article on Publisher Site

Abstract

Mode I fracture cleavage testing was conducted on wood bonded with poly(vinyl acetate-co-NMA) latex adhesive containing two types/degrees of cross-linking: (1) cross-linking through AlCl 3 catalysis of N -methylolacrylamide (NMA) comonomer; and (2) additional cross-linking using a phenol-formaldehyde resol additive, in addition to AlCl 3 catalysis. The formulation lacking the phenolic additive performed well under dry conditions; but it completely failed during testing as a result of accelerated weathering. In contrast, fortification with the phenolic additive provided durability against accelerated weathering. In an effort to understand the effects of accelerated weathering, parallel-plate dynamic mechanical analysis was applied to freestanding neat adhesive films and to wood-bonded films (composites). Accelerated weathering dramatically altered the viscoelastic response of films and composites that lacked the phenolic additive; weathering caused a second, broad and reversible relaxation near 100°C, which might be because of softening of the poly(vinyl alcohol) interfacial agent used during emulsion polymerization. In contrast, samples formulated with the phenolic additive only displayed the typical base-polymer glass transition. Correlation of the fracture testing and the rheological analysis suggests that the phenolic additive promotes adhesive durability by cross-linking the interparticle boundaries, where poly(vinyl alcohol) is believed to reside.

Journal

Holzforschung - International Journal of the Biology, Chemistry, Physics and Technology of Woodde Gruyter

Published: May 1, 2006

Keywords: DMA; dynamic mechanical analysis; fracture test; latex adhesives; parallel-plate rheology; wood/adhesive interactions

There are no references for this article.