No abstract

Acknowledged that polycaprolactone (PCL) is one of the prospective polymer category. This is due to PCL has a great mechanical properties, biodegradability, and excellent mixing ability with various other polymers. The effective technique to get PCL is through the ring opening polymerization (ROP) of caprolactone (ε-CL) using metal catalyst. The aims of this research was to determine a reasonable reaction mechanism of the ROP of ε-CL using bis(benzoylacetonato)zirconium(IV) chloride catalyst. In this investigation the PM3 semi-empirical method was assigned to calculate the monomer, intermediate structures, and polymer structure. Then, to compute and visualize geometry structure was employed by using the HyperChem 8.0 program. This software operates on the Windows 07 system. The calculation results imply that to get PCL using bis(benzoylacetonato)zirconium(IV) catalyst required a few steps i.e. coordination ε-CL in metal center, χ-CL deprotonation, the insertion of ε–CL, and propagation of the chain.

Poly(ε-caprolactone) (PCL) is one of the promising polymers because it can be utilized as a substitute for petroleum-based polymers that are diffi cult to biodegrade in nature. PCL has non-toxic properties, high crystallinity, and biodegradable. Therefore, this polymer is widely used for medical purposes and environmentally friendly packaging. The purpose of this study was to compare the degree of polymerization, catalytic activity and thermal properties between PCL produced using bis(benzoylacetonato)zirconium(IV) catalyst (2a) with the PCL produced using other bis(β-diketonato)zirconium(IV) chloride catalyst (2b, 2c). In this research, ring opening polymerization (ROP) of ε-caprolactone (ε-CL) was performed by using complex 2a as a catalyst. The polymerization reaction lasts for 4 h at 100°C. The results of the research showed that ε-CL was successfully polymerized as proven in the results of its characterization. The molecular structure of the obtained PCL was analyzed by using FTIR, 1 H NMR, 13 C NMR, XRD, DSC, and TGA. The PCL produced in this study was a semicrystalline polymer. Meanwhile, a Mulliken charge of zirconium central atom in complex 2a-2c was also measured. In Mulliken charge analysis, the Mulliken charge of complex 2c has the highest Lewis acidity in comparison with complex 2a and 2b.

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