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Madison, WI 53726-2398
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Title: Mechanical Characterization of Wood-Adhesive Interphase with an Improved Nanoindentation Technique

Source: In: Proceedings of the 55th International convention of Society of Wood Science Technology, August 27-31, 2012 - Beijing, China. p. 6.

Author(s)Yu, Yan; Frihart, C.R.; Jakes, J.E.; Jiang, Z.H.

Publication Year: 2012  View PDF »

Category: Conference Proceedings
Associated Research Project(s):   FPL-4707-2B

Abstract: An improved nanoindentation method was used to assess the hardness and elastic modulus of the bulk adhesive and wood cell walls within wood-adhesive bondlines. Improvements include a specimen preparation technique that does not require any embedment. Also, a structural compliance method was used to remove from the nanoindentation measurements artifacts arising from edges near to the nanoindents and specimen-scale flexing. Interphases between southern pine and the four adhesives phenol formaldehyde (PF), urea formaldehyde (UF), epoxy, and emulsion polymer isocyanate (EPI) were characterized. The hardness of PF was measured to be 0.87 GPa, nearly 2-3 times larger than UF, epoxy and EPI. The elastic modulus of PF was 8.8 GPa, comparable to that of UF but nearly 2-3 times larger than that of epoxy and EPI. Furthermore, we observed that the hardness of wood cell walls increased near the adhesive line for PF and UF bondlines, which strongly supports the idea that some low-molecular components of PF and UF infiltrate into the wood cell wall and improve its mechanical performances after curing. Similar increases were not found for epoxy and EPI bondines. Our results support that the widely known durable and strong bonding of wood with PF is related to the excellent mechanical performances of PF resin itself and its ability of infiltrate into and reinforce wood cell walls.

Keywords: wood bonding; interphase; nanoindentation; adhesive

Publication Review Process: Non-Refereed (Other)

File size: 218 kb(s)

Date posted: 08/26/2013
RITS Product ID: 64947
Current FPL Scientists associated with this product (listed alphabetically)
Frihart, Charles R.
Research Chemist
Jakes, Joseph
Research Materials Engineer

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