Synthesis And Characterization Of Copolymeric Aliphatic-Aromatic Esters Derived From Terephthalic Acid, 1,4-Butanediol, And E-Caprolactone By Physical, Thermal, And Mechanical Properties And Nmr Measurements

In this study, a series of aliphaticaromatic poly(butylene terephthalate-co-e-caprolactone) (PBTCL) copolyesters were synthesized from various monomeric compositions of terephthalic acid (TPA), 1,4-butanediol (BDO), and e-caprolactone (CL) in the presence of tetrabutyl titanate (Ti(Obu)4) and stannous octoate (Sn(Oct)2) as catalysts through a combination of polycondensation and ring opening polymerization. A significant increase in the melting temperature (Tm) of copolyesters was observed by increasing the TPA/(CL+TPA) molar ratio, starting from the low end (Tm 66.2 degrees C) of pure poly-e-caprolactone PCL upward. We found that PBTCL-50, which has a TPA/(CL+TPA) 50% molar ratio and polycondensation at 260 degrees C for 1.5 h, resulted in a proper Tm of 139.2 degrees C that facilitates thermal extrusion from biomass or other biodegradable polymers of similar Tm. The numberaverage molecular weight (Mn) of 7.4 x 104 for PBTCL-50 was determined from the intrinsic viscosity [?] by using the Berkowitz model of Mn = 1.66 x 105[?]0.9. Good mechanical properties of PBTCL-50 have been shown by tensile stretching experiment that indicates tensile strength, elongation, and Young's modulus are 11.9 MPa, 132%, and 257 MPa, respectively. Polymers with aforementioned properties are suitable for manufacturing biodegradable plastic films for downstream agricultural applications or merely for trash bag. This article reveals that the PBTCL-50 contains all five monomers with different molar ratios and characteristical linkages between each other. The novel structure was furthermore analyzed by 1H- and 13C-NMR spectroscopy. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013