Effects of resin impregnation and process parameters on some properties of poplar LVL
1994
Chui, Y.H. | Schneider, M.H. | Zhang, H.J.
This paper describes a study to produce qualitative information on the effects of resin impregnation of veneer and process parameters on properties of poplar (Populus spp.) laminated veneer lumber (LVL). In the study, two types of LVL boards (nominally 255 by 175 by 25 mm) were made; one had all veneers impregnated and the other had only the outer veneers impregnated with a water-soluble, phenol-formaldehyde resin. Specimens were cut from these boards and tested for mechanical properties, including modulus of elasticity and modulus of rupture in bending and horizontal shear strength. Cut specimens were also evaluated for compression (densification), density, and thickness swelling after a 24-hour water-soak. Untreated LVL specimens were made and tested for reference purposes. Compared with untreated LVL, both types of treated LVL had improved mechanical properties and dimensional stability. The effects of process parameters on properties of LVL were also studied and are discussed in this paper. It was found that increasing press pressure, reducing time to maximum pressure, and increasing initial veneer moisture content produced greater densification of boards. In comparison with thickness swelling results, it is noted that densification directly influenced thickness swelling of LVL. This preliminary study has provided qualitative information based on testing of specimens from small boards. Future research should study the interaction of process parameters using larger board sizes.
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