Ageing periods, polyurethane

The second method for the addition of BHMBE in polyurethane consisted of a simple mixing of the stabilizer with the solution of polymer following the classic route. From these solutions test-pieces were prepared and subjected to the sun light in the condition of atmospheric ageing process for 120 days and were tested periodically from the view-point of the mechanical properties (Tables 4.24 and 4.25) [64]. 

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