Vacuum-pressure soak test

Resin synthesis, adhesive formulation, and evaluation techniques are described by Clark et al. (3,4) Plywood shear specimens were prepared according to U.S. Product Standard PS 1-83 for exterior plywood (5). Glulam shear specimens were tested according to the American Institute of Timber Construction (AITC) standards AITC-T107 and AITC-T110 for dry shear and vacuum-pressure soak (3). Glulam test specimens were also subjected to a 2-hour boil treatment (not an AITC test) prior to shear (7,8). 13C-NMR spectra were recorded at 100.6 MHz on a Bruker AM-400 NMR spectrometer. Gel permeation chromatography... 

How to determine sufficient durability of wood bonds is still of great concern. ASTM D 2559 has been considered the ultimate test, but there has been little discussion of forces on the bondline during this test and how representative they are of those experienced in the actual application. The test involves cycles of rapid water soaking by vacuum-pressure soaks followed by rapid drying in a hot oven. Not surprisingly, this test causes considerable distortion and fracturing of the wood itself because the dimensional changes are so rapid that the wood does not... 

Evaluating the integrity of the container can be done in several ways. Two of the most common tests are dye penetration and microbial ingress. Container closure systems stored in a dye solution and exposed to pressure and vacuum cycles are examined for dye leakage into the container. The microbial ingress is similar in fashion but determines the microbial contamination of the contents when soaked in a media contaminated with bacteria. Other quantitative tests that can be run are vacuum/pressure decay, helium mass spectrometry, and gas detection. 

D-3110 (see wood adhesive specifications), tests for strength retained after exposure and sets forth minimum performance criteria. Exposures include atmospheric water soak, vacuum-pressure water soak, boiling, and exposure to elevated temperatures in an oven. Whenever dealing with adhesives falling in the categories covered by D-3110, durability should certainly be tested that way. However, these procedures almost certainly have other useful wood adhesive testing applications too. 

---