## Results and Discussion
\begin{table}
\begin{tabular}{l} \hline
**Wave number in cm -1** **Group and band** \\ \hline _Poly(\(\varepsilon\)-caprolactone)_ \\
2943 (\(\mathrm{u_{as}CH_{2}}\)), 2862 (\(\mathrm{u_{s}CH_{2}}\)), 1721 (\(\mathrm{vC}\)=O), 1291 (\(\mathrm{C}\)-O and \(\mathrm{C}\)-\(\mathrm{C}\)) 1240 (\(\mathrm{u_{as}COC}\)), 1190 (\(\mathrm{vOC}\)-O), 1170 (\(\mathrm{u_{s}COC}\)), 1157 (\(\mathrm{C}\)-O and \(\mathrm{C}\)-\(\mathrm{C}\)) \\ \hline _Polylactides_ \\
2997 (\(\mathrm{u_{as}CH_{3}}\)), 2947 (\(\mathrm{u_{s}CH_{3}}\)), 2882 (\(\mathrm{vCH}\)), 1760 (\(\mathrm{vC}\)=O), 1452 (\(\mathrm{\delta_{as}CH_{3}}\)), 1348-1388 (\(\mathrm{\delta_{s}CH_{3}}\)), 1368-1360 (\(\mathrm{\delta_{i}CH+\delta_{s}CH_{3}}\)), 1315-1300 (\(\mathrm{\delta_{2}CH}\)), 1270 (\(\mathrm{\delta CH+vCOC}\)), 1215-1185 (\(\mathrm{u_{as}COC+r_{as}CH_{3}}\)), 1130 (\(\mathrm{r_{as}CH_{3}}\)), 1100-1,090 (\(\mathrm{u_{s}COC}\)), 1045 (\(\mathrm{vC}\)-\(\mathrm{CH_{3}}\)), 960-950 (\(\mathrm{rCH_{3}+vCC}\)), 875-860 (\(\mathrm{vC}\)-COO), 760-740 (\(\mathrm{\delta C}\)=0), 715-695 (\(\mathrm{\gamma C}\)=O), 515 (\(\mathrm{\delta_{1}C}\)-\(\mathrm{CH_{3}+\deltaCCO}\)), 415 (\(\mathrm{\delta CCO}\)), 350 (\(\mathrm{\delta_{2}C}\)-\(\mathrm{CH_{3}+\delta COC}\)), 300-295 (\(\mathrm{\delta COC+\delta_{2}C}\)-\(\mathrm{CH_{3}}\)), 240 (\(\mathrm{\tau CC}\)) \\ \hline \end{tabular}
\end{table} 
Table 3: Main absorption bands of the synthesized polyestres (spectrum recorded from a KBr pellet). The molecular mass of PCL, PLA and PLLA is dependent on the monomer/carnitine molar ratio (Table 1). The influence of the monomer/carnitine feed ratio on the molecular weight of polyesters was studies at three levels (25:1, 50:1, 100:1). As shown in Table 1, the PCL products were obtained with M\({}_{\rm n}\) (from GPC) of 1800, 3800 and 6600 Da for PCL-2, PCL-3 and PCL-5, respectively. For PLA, M\({}_{\rm n}\) (from GPC) amounts to 1700, 3200 and 4600 Da for PLA-1, PLA-2 and PLA-5, respectively. It was found that the molar mass of the polyesters increased with the monomer/carnitine feed ratios. On the other hand, according to M\({}_{\rm n}\) of polyesters, the PCL and PLA conversion had tendency to decrease with the increasing monomer/carnitine feed ratio. For PCL-2, PCL-3, PCL-5, PLA-1, PLA-2 and PLA-5 the corresponding monomer conversion values were 85%, 71%, 67%, 62%, 53% and 36%, respectively. The reaction yield was determined by the weight method. The homo- and copolymerization reactions of CL, LA and LLA were repeated twice for each combination. The results were in good agreement with one another (reproducibility of them was about 5-10%). Both, the conversion and molecular mass of the polymers increased, when the reaction temperature was raised from 120 to 160\({}^{\circ}\)C.  
The average molecular mass values of PCL determined by the MALDI-TOF method are in the 1400-4800 Da range and according to the viscosity measurement are in the 1200-6500 Da range. For polylactides, the M\({}_{\rm n}\) values determined from MALDI-TOF and the viscosity measurements are 2100-3800 and 1000-5100 Da, respectively. M\({}_{\rm n}\) determined from GPC for CL oligomers is in the range of 1500-8800 Da (polydispersity indexes 1.1-1.3). For polylactides the M\({}_{\rm n}\) values are 1200-4600 Da and M\({}_{\rm w}\)/M\({}_{\rm n}\) = 1.1-1.3. Figure 3: MALDI TOF spectra of the product of CL polymerization in the presence carnitineine and SnOct\({}_{2}\). A10(B10) = -[C(O)CH(CH\({}_{3}\))O]\({}_{10}\)-, etc (PCL-2). The molecular mass values averaged over those of the obtained polymers were roughly in agreement with the theoretical molecular weights calculated from the feed ratio of the monomer to carnitineine as well as the number average molecular mass determined from MALDI-TOF and GPC. Finally, it should be mentioned, that the carnitineine/SnOct\({}_{2}\) system was quite effective in the polymerization of \(\varepsilon\)-caprolactone, L-lactide and _rac_-lactide. The yield of PCL was in the range of 62-93 %, and for PDLA in the range of 30-68 %.