Thickness swell values

A comparison of the durability of the adhesive bonds formed by the two binders is provided by the wet internal bond and by the thickness swell values shown graphically in Figures 5 and 6, respectively. The former, measured after a 2 hour water boil, are strikingly superior for the Desmodur PU-1520A 20 vs. the phenolic binder at all press times. The same can be said for thickness swell after 2 and 2k hour water soaks. 

Results. Physical properties for the standard, or control, panels are given in Table VIII. Although the Mondur MR panels were cured two minutes less and at 50 F (28 C) lower press temperature, original strength properties and thickness swell values are clearly superior to those of the phenolic-bound panels. There did appear to be a slight lag in modulus of rupture retention after accelerated aging. 

As for water resistance, linear swelling was not greatly influenced by the wood content, showing values in the range of 0.06-0.28%. However, water absorption and thickness swelling showed a tendency to increase with an... 

The pattern used for cutting test specimens is shown in Figure 3. The property values given in this report are mean values of the number of specimens indicated times two since each board was duplicated. Densities were measured on all thickness swell, internal bond (IB) and bending modulus specimens before those respective tests were run. 

Values of N l2xyx and HplHp are calculated and listed in Table 3.4, but they are unreasonably low at high shear rates. This is due to the predictions of the PTT model at high shear rates when only a single relaxation time is used. Hence, the PTT model does not allow us to properly estimate thickness swell. 

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