## 3 Results and Discussion
### Effect of CNT Types and CNT Concentrations on Suspension Polymerization of Styrene and nBA
This explains why the best conversions were achieved with CNTs modified with boron, as shown in Table 7; in all cases, the conversions were 90% or above, and it is thus clear that there were no retarding/inhibiting effects. Other interesting results were found with particle sizes in the micron range; of all the concentrations tested, the one with 0.25 wt% proved the best for obtaining encapsulated CNTs by suspension-polymerizing styrene and nBA. Suspension Polymerization of Styrene and nBA in the Presence of CNT-D and CCA (MEC-88) in Different Concentrations  
[PERSON] et al. [36] reported that suspension polymerization is a widely used technique for producing latex particles, which have a broad range of applications in coatings, adhesives, and toners. nBA and styrene are two commonly used monomers in suspension polymerization, and their copolymers have been widely used in toner applications because of their high charging characteristics and excellent print quality [37]. Since the present work aims to develop new materials for toner applications, CNTs should be either encapsulated or attached to the polymerized particles. According to [PERSON] and [PERSON] [38], CNT encapsulation--being attached to the polymerized particles--is necessary to improve the particles' dispersion and enhance their electrical conductivity. A CCA must also be inserted in polymerized particles or stuck on the surface [39] to improve the charging characteristics of the resulting toners. In the present study, MEC-88, which is a negatively charged CCA type, was dissolved in styrene before polymerization took place to ensure its even distribution throughout the polymerization process. Table 8 presents the particle size, measured by DLS, for converting polymerized particles using MEC-88 concentrations ranging from 0.05 wt% to 0.42 wt%, and Figure 2 plots the conversions against the MEC-88 concentrations. It is evident that conversion decreased with greater MEC-88 concentrations, implying an inverse relationship between them. Figure 2 shows that the maximum conversion (75%) was achieved with the smallest concentration of MEC-88 (0.05 wt%), but the conversion surprisingly did not increase to more than 75% in any case, making the conversion undesirable for toner material production. It is well known that the presence of CB retards or inhibits most types of radical polymerization because it is a potent radical scavenger [40]. In addition, the functional groups on the surfaces of CB (mostly the carbonyl group) interact with primary or propagating radicals, resulting in reaction retardation/inhibition [31; 37]. More details on the retarding/inhibiting effects of the carbonyl group were reported by [PERSON] et al. [26], \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline
**Sample Code** & **CCA Con. (g)** & **CCA wt.\%** &
\begin{tabular}{c} **CNT-D Con.** \\ **(g)** \\ \end{tabular} & \multirow{2}{*}{**CNT-D wt.\%**} & \multirow{2}{*}{**Conversion**} & \multirow{2}{*}{**DLS Measurement**} \\ \cline{4-4} \cline{6-7}  & & & & & **Z-Average** & **PDI** \\ \hline SP-CNT-D-MEC-88-1 & 0.102 & 0.42 & 0.034 & 0.14 & 12 & 4032 & 1.00 \\ SP-CNT-D-MEC-88-2 & 0.068 & 0.28 & 0.034 & 0.14 & 58 & 5882 & 0.16 \\ SP-CNT-D-MEC-88-3 & 0.034 & 0.14 & 0.034 & 0.14 & 68 & 5077 & 0.50 \\ SP-CNT-D-MEC-88-4 & 0.017 & 0.07 & 0.034 & 0.14 & 70 & 4576 & 1.00 \\ SP-CNT-D-MEC-88-5 & 0.011 & 0.05 & 0.034 & 0.14 & 75 & 6910 & 0.57 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Suspension polymerization of St and nBA in the presence of CNT-D and five different concentrations of MEC-88. but to relate this observation to the phenomena discussed in the previous paragraph it would be fruitful to look at the chemical characteristics of MEC-88 (see Figure 3). From Figure 3, it can be seen that MEC-88 has a carbonyl group. [PERSON] et al. [41] described how carbonyl groups harbored in a chemical structure likely interact with radicals during the polymerization process, thereby retarding or inhibiting it.