Next, WPC 1 and 2 were measured with method no. 2 to deter- mine the amounts of the polymer and wood flour fractions (Fig. 5). The two curves can each be divided into four steps of mass loss [15]. Within each step, a specific weight loss occurs (Table 3) so the sum of all weight losses should theoretically add up to 70% for the wood flour in WPC 1 and 2. However, this theoretical weight loss value is not reached because a 100% separation of individual components cannot be achieved due to the overlap of the curves (Fig. 4). Step separation between steps 2 and 3 is not possible because these steps overlap. Each peak of the DTG-curve should reach the baseline for a detailed analysis (Fig. 5). Using dynamic heating, at 400 ◦ C no exact step separation is possible. Therefore, an isothermal step between 300 and 500 ◦ C was introduced. This was done next in Section 3.3.
In Table 3, steps 1, 2 and 4 were assigned to the mass loss of wood flour while step 3 was assigned to the polymer fraction, based on the TGA-measurements of the single components (wood flour, PP- copolymer, MAPP and wax; Fig. 4). It can be seen that the results deviate from the expected amounts for the wood and polymer fractions strongly.