Rate- and Duration-of-load Behavior of Lab-made Structural Flakeboards

Rate- and Duration-of-load Behavior of Lab-made Structural Flakeboards
Author: J. Dobbin McNatt
Publisher:
Total Pages: 8
Release: 1985
Genre: Particle board
ISBN:

Tests of structural use panels under different loading conditions provide basic information for establishing design stresses. This paper reports the effects of loading rate in tension and bending and of duration of load in tension on the properties of four lab-made structural flakeboards, (two of which had aligned flakes). The objective was to determine if these panels-made from larger, engineered flakes-behaved the same as commercial particleboards-made primarily from planer shavings and sawdust-that were evaluated in an earlier study. For specimens loaded to failure at different rates of deformation, strength decreased 12 pct in tension and 8 pct in bending with each tenfold increase in time to maximum load. Modulus of elasticity decreased 4 to 5 pct. For specimens loaded in tension at constant stress levels from 50 to 90 pct of static strength, time to failure increased tenfold with each 8 pct decrease in stress. These results for the lab-made structural flakeboards are essentially the same as those reported earlier for commercial particleboards.

Adhesion in Cellulosic and Wood-Based Composites

Adhesion in Cellulosic and Wood-Based Composites
Author: John F. Oliver
Publisher: Springer Science & Business Media
Total Pages: 255
Release: 2013-03-09
Genre: Science
ISBN: 1468489836

Cellulose is a versatile and renewable natural resource which has attracted increasing attention in the last decade, expecially after the energy crisis of 1973. Apart from its extensive use as asolid product, wood is the most important source of cellulose fibres for papermaking and is also widely used as a source of energy. The form and availability ot· the forest provides a great opportunity for technological improvement and innovation in the future to satisfy the foreseeable increasing demand for wood based products. For example, North American sawmills and plywood mills presently recover only about 45 to 55% of logged wood while the remainder is disposed as waste, if it is not used in pulp manufacturing. In addition, top and branch wood, and logs from non-commercial species which are presently not recovered from the logging sites could provide an abundant and relatively inexpensive resource for the manufacture of composite products. Other valuable potential sour ces of cellulosic materials are waste paper and agricultural waste. A composite is the consolidation of two polymerie materials such that one of the components acts as the adhesive binder while the other forms the substrate matrix. In some cases, the matrix and the adhesive may be the same materials. To maximize the adhesion potential of the composite, the properties of the substrate which can enhance, hinder or complicate the development of optimum adhesion should be thoroughly explored and identified.