## 3 Result
### One-Step Process
The water imbibed by fillers, in fact, could cause an increase of total water content leading to the formation of higher voids volume during curing process. For this reason, the addition of sawdust strongly increases the average pores size. \begin{table}
\begin{tabular}{c c} \hline \hline
**Sample** & **Average Pores Diameter (\(\upmu\)m)** \\ \hline
**P100N** & 691.39 \(\pm\) 205.01 \\
**OFMSW\_P100N\({}_{\text{dual step}}\)** & 50.48 \(\pm\) 24.65 \\
**OFMSW\_P100N\({}_{\text{one step}}\)** & 68.94 \(\pm\) 34.83 \\
**OFMSW\_P100N\({}_{\text{10s one step}}\)** & 260.35 \(\pm\) 32.77 \\
**OFMSW\_P100N\({}_{\text{10c one step}}\)** & 151.48 \(\pm\) 14.68 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Average dimension of the pores of one step and dual step process cured samples. Figure 7: Optical microscope analysis of P100N (**A**), OFMSW_P100N\({}_{\text{dual step}}\) (**B**), OFMSW_P100N\({}_{\text{one step}}\) (**C**), with sawdust as additive - OFMSW_P100N\({}_{\text{10s}}\)_one_step (**D**) and with coffee powder added - OFMSW_P100N\({}_{\text{10c}}\)_one_step. (**E**) samples (magnification 50X). The effect of the porosity on the mechanical properties of the sample were evaluated by compression tests. Typical flexural properties on P100N samples produced by dual-step and one-step processes are reported in Table 4.  
Compared to the UF P100N system, addition of OFMSW in the dual step process allows a significant increase of strength and modulus. The increase of the strain at break, however, is much more limited. In this case, in facts, the difference between the blend UF/OFMSW and neat UF is comparable to the standard deviation associated to the measurements, also reported in Table 4.  
One way analysis of variance (ANOVA) [19] was performed on the strain at break. With one factor levels (UF P100N and OFMSW/UF blend) and five degrees of freedom for each level (six tests at each level) it is possible to estimate \(p=0.29\), which is much higher than the significance level \(\alpha=0.05\), indicating that the strain at break of the two averages are statistically equivalent, and the differences can be explained by considering the error associated to the measurement. The production of UF/OFMSW blends by the one step process, though allows the reduction of the time and the costs associated to the treatment, involves a significant decrease of the flexural modulus. Even in this case, ANOVA was performed on the flexural strength and strain at break, also in view of the fact that the difference between the averages is comparable to the standard deviation of the measurements. For the strain at break, \(p=0.77\) again indicates the statistical equivalence between the averages, whereas for the flexural strength, \(p=0.01\) indicates that the one step process involves a statistically significant reduction compared to the dual-step process. This can be ascribed to a different evaporation rate for the two processes. In particular, the dual step process involves a further addition of water, which was lost during the sterilization step. On the other hand, the one-step process is characterized by the simultaneous cure and sterilization, further addition of water is not required. In the first process, the evaporation of water occurs at lower temperature reducing the release during the cure and, consequently, the porosity of the final component; in the latter one, water is entrapped in the OFMSW, the evaporation starts at higher temperatures, during the cure, causing a higher average pores diameter (Table 4). However, it is also worth observing that in any case the flexural modulus and strength of UF/OFMSW produced by one step process are higher than the corresponding properties of UF P100N. In this case, direct comparison between the averages by ANOVA provided \(p=1.3\times 10^{-5}\) for the flexural strength and \(p=1.3\times 10^{-3}\) for the modulus. In contrast, for the strain at break, \(p=0.14\) again indicates the statistical equivalence for UF P100N and UF/OFMSW produced by one step process.