Catalytic Synthesis and Characterization of Biodegradable ...
Catalytic Synthesis and Characterization of Biodegradable ...
Catalytic Synthesis and Characterization of Biodegradable ...
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Chapter 4<br />
attributed to the amide group. The GPC elution curve for PTAm-g-PLA gave a unimodal peak,<br />
which indicated that there was no undesired homopolymer residue in the final product. Based<br />
on these results, it was concluded that the PTAm-g-PLA copolymers were successfully<br />
prepared by this method.<br />
Figure 4.3 FTIR spectra <strong>of</strong> PTAP-g-PLA2 (A) <strong>and</strong> PTAm-g-PLA2 (B).<br />
4.3 Electrochemical Properties<br />
Based on the presence <strong>of</strong> the nitroxide radicals, the copolymers exhibited<br />
electrochemically reversible properties similar to that <strong>of</strong> TEMPO. The cyclic voltammogram<br />
(CV) <strong>of</strong> the copolymer at different scan rates were shown in Figure 4.4. The CV curves for<br />
the copolymer were recorded in the potential range <strong>of</strong> 0.00 to 1.30 V. The response revealed a<br />
highly reversible redox property at around 0.63 V vs. Ag/AgCl, which was assigned to the<br />
oxidation <strong>of</strong> the nitroxide to the corresponding oxoammonium cation. The redox potential<br />
(0.63 V vs. Ag/AgCl) was in good agreement with that <strong>of</strong> the PTAm homopolymer (0.68 V vs.<br />
Ag/AgCl). Moreover, the peak current is proportional to the sweep rate, suggesting a fast<br />
electron transfer process in the copolymer film.<br />
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