Influence of a resorcin[4]arene core structure on the spatial directionality of multi-arm poly(ε-caprolactone)s

• Published in: RSC advances 2014-01, Vol.4 (32), p.16864-16870
• Main Authors: Wu, Ruizhi, Al-Azemi, Talal F., Bisht, Kirpal S.
• Format: Article
• Language: English
• Subjects: Controllers; Crystallinity; Differential scanning calorimetry; Initiators; Nuclear magnetic resonance; Polymers; Programmable logic devices; Thermal properties
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C3RA47678B

Highly crystalline directional polycaprolactones (PCLs) based on two tetrahydroxy methyl resorcin[4]arene initiators were synthesized by a “core first” method via ring-opening polymerization of ε-caprolactone catalyzed by Sn(Oct) 2 in bulk at 120 °C. The synthesized polymers were characterized by nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and wide angle X-ray scattering (WAXS). The structures of tetra-arm PCLs based on resorcinarenes were confirmed by 1 H NMR analysis. The thermal properties were evaluated using DSC and TGA. The spatial directionality, a consequence of the rigid bowl shaped resorcinarene cavitand core, of the PCL chains influenced the thermal properties and crystallinity of the polymers. The melting temperature ( T m ), decomposition temperature ( T d ) and % crystallinity (% X c ) of the directional PCL from the rigid core cavitand 2c were significantly higher than those of the linear counterpart and the PCL from the somewhat flexible cavitand core 3c . The data implies that the spatial directionality of the polymer chains in multi-arm polymers can be used to manipulate their thermal and physical properties. Detailed analysis of the two tetra-hydroxy resorcinarene initiators and a comparison with linear PCLs is discussed.