## 3 Experimental Results
According to the results reported in Figure 6 and Table 4, the higher specific stiffness is attributed to the more homogeneous porous structure, which characterized the OF_P100N_C_3 sb system. Finally, a rough cost estimation of the developed procedure is presented. Such cost estimation must account for the fact that, compared to the standard processing of the UF resin, an additional cost is given by the sterilization carried out at 120 \({}^{\circ}\)C, but the production of the blend, allows to reduce the cost due to the reduced UF consumption. \begin{table}
\begin{tabular}{c c} \hline \hline
**Sample** & **Average Pores Diameter (\(\mu\)m)** \\ \hline OF_P100N & 68.94 \(\pm\) 34.83 \\ OF_P100N_C\_3 sb & 348.62 \(\pm\) 27.59 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Average pore diameter of the P100N based samples with and without sodium bicarbonate (3% wt). Figure 6: (**A**) Optical microscopy image of OF_P100N_one step [1]; (**B**) optical microscopy image of OF_P100N_C_3 sb. Figure 7: Comparison of specific modulus for the uncatalyzed and catalysed OF_P100N systems with OF_P100N_3 sb. In the energy estimation, the following formula was used:  
\[E=\Big{(}w_{water}c_{p,water}+w_{solid}c_{p,solid}\Big{)}\Delta T+w_{water}\Delta H _{ev,water} \tag{2}\]  
where \(w\) is the weight fraction, \(c_{p}\) is the specific heat, \(\Delta T\) is the heating required to attain the OFMSW sterilization, and \(\Delta H_{ev}\) is the latent heat of vaporization. In the following analysis, it is considered that, according to the previous work [1], \(w_{water}=0.7\) and \(w_{solid}=0.3\). In addition, considering heating of the OFMSW at 120 \({}^{\circ}\)C, with a room temperature of 30 \({}^{\circ}\)C, the specific heat of the solid fraction of OFMSW [27] and the specific heat and latent heat of the vaporization of water, the total energy required for sterilization can be estimated to be 1850 K] [27], as reported in Table 5.  
With an energy cost of about \(3.9\times 10^{-5}\)\(\upxi\)/KJ [28], the unitary cost of the sterilization process can be estimated to be \(C_{ULOFMSWst}=0.07\)\(\upxi\) for each Kg of treated OFMSW. On the other hand, when adding the OFMSW in the blend with UF, the cost of the material can be estimated as:  
\[C=C_{u,OFMSWst}w_{OFMSW}+C_{u,UIF}w_{UIF}+C_{u,additive}w_{additive} \tag{3}\]  
where \(w\) indicates the weight fraction of each component, and \(C_{u}\) is the unitary cost of each of the materials present in the blend. The value of \(w_{OFMSW}\) is evaluated on the blends after curing and water evaporation, and therefore can be obtained from the data reported in Table 1 by neglecting the water content as:  
\[w_{OFMSW}=\frac{M_{OFMSW}}{M_{UIF}+M_{OFMSW}+M_{additive}} \tag{4}\]  
It should be emphasized that, in Table 1, the addition of coffee or sawdust was done at the expense of the UF, and therefore, for each of the blends of Table 1, \(w_{OFMSW}=0.144\). the value of \(w_{additive}\) was estimated by the formula equivalent to Equation (4) as:  
\[w_{additive}=\frac{M_{additive}}{M_{UIF}+M_{OFMSW}+M_{additive}} \tag{5}\]  
The unitary cost of each component was taken as: \(C_{ULIF}=1.1\)\(\upxi\)/Kg (data provided by the resin supplier) and \(C_{u,OFMSWst}=0.07\)\(\upxi\)/Kg. The unitary cost of the additives like coffee or sawdust was taken equal to zero. The estimated values for C are reported in Table 6; in any case, for the developed blends, the cost is lower than that of the neat matrix. In addition, the cost decreases with the increasing amount of coffee or sawdust. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Formulation** & \(w_{OFMSW}\) & \(w_{additive}\) & \(C\) **(\(\upxi\)/Kg)** \\ \hline \hline Neat matrix & 0 & 0 & 1.1 \\ OFMSW/UF blend & 0.144 & 0 & 0.95 \\ OFMSW/UF blend and 5\% other additive & 0.144 & 0.067 & 0.88 \\ OFMSW/UF blend and 10\% other additive & 0.144 & 0.13 & 0.80 \\ OFMSW/UF blend and 15\% other additive & 0.144 & 0.2 & 0.73 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Total cost balance for the production of the OFMSW/UF blends.