A systematic study of macrodiols and poly(ester-urethanes) derived from α,ω-hydroxy telechelic poly(ε-caprolactone) (HOPCLOH) with different ether [CH2CH2O]m groups. Synthesis and characterization
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α,ω-Hydroxy telechelic poly(ε-caprolactone) (HOPCLOH) was synthesized by ring-opening polymerization (ROP) of ε-caprolactone (ε-CL).The ROP was catalyzed by ammonium decamolybdate in the presence of ether diols [HO-(CH2-CH2-O)m-H] (where m = 2, 3, 4, 5, 6, and 8) as initiators. The homopolymer HOPCLOH was obtained with the ether group (EG) [HO-PCL-(CH2-CH2-O)m-PCL-OH (HOPCLOH)] as part of the backbone of the polyester with a systematic increase in the segment of the EG. The number average molecular weight (Mn) for all samples were similar in the range of oligomers (Mn = 1240–1510 Da) to have a significant effect of the EG. The effect of the EG on the physical properties was evaluated by differential scanning calorimetry (DSC) where the crystallinity of HOPCLOH and the size of the EG showed a relationship inversely proportional. Poly(ester-urethanes) (PEUs) derived from HOPCLOH exhibited an elastomeric behavior, where long chains of EG induced poor mechanical properties. The use and selection of the ether diols as initiators in the ROP of CL to synthesize HOPCLOH was not trivial because these EG substituents affected the crystallinity, and the mechanical properties of their PEUs.
KeywordsPoly(ε-caprolactone) Hydroxy telechelic polyester Ether group Poly(ester-urethane) Crystallinity
José E. Báez thanks the “Consejo Nacional de Ciencia y Tecnología” (CONACYT) (Proyecto CONACYT Ciencia Básica 284893), Dirección de Apoyo a la Investigación y al Posgrado (DAIP) at University of Guanajuato (UG), and “Sistema Nacional de Investigadores (SNI)” in México for financial support of the work. José E. Báez also thanks to Ángel Marcos-Fernández for believing in these ideas and providing financial support for the reagents through the project MAT2017-87204-R from the Ministry of Economy and Competitiveness (MINECO) of Spain. José E. Báez also thanks to the UG for the recent opportunity to work as an Assistant Professor. Marvin was used for drawing, displaying, and characterizing chemical structures, substructures, and reactions (Marvin Sketch 6.1.3, 2013, ChemAxon; http://www.chemaxon.com); a free software program with an academic license was provided by ChemAxon. Finally, José E. Báez thanks to Gema Reina Mendieta for the acquisition of the NMR spectra.
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