Surface Structure and Stereocomplex Formation of Enantiomeric Polylactide Blends Using Poly(dimethyl siloxane) as a Probe Polymer

• Published in: Macromolecular symposia Vol. 239; no. 1; pp. 91 - 96
• Main Authors: Lee, Jin-Kook, Kim, Mi-Ra, Lee, Hyun-Jeong, Chung, Ildoo, Lim, Kwon Taek, Jeon, Sangik, Lee, Won-Ki
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.06.2006; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Applied sciences; Blends; Crystallites; Exact sciences and technology; Inorganic and organomineral polymers; Physicochemistry of polymers; poly(d-lactide); poly(l-lactide); Polymer blends; Properties and characterization; Segregations; Silicone resins; Siloxanes; stereocomplex; Stereocomplexes; surface segregation; Surface structure; Triblock copolymer; Lactic acid polymer; Polymer blends; Optically active polymer; Surface segregation; Lactic acid copolymer; Composition effect; Stereocomplex; Experimental study; Dimethylsiloxane copolymer; Comparative study
• ISBN: 3527317457; 9783527317455
• ISSN: 1022-1360; 1521-3900
• DOI: 10.1002/masy.200690115

In the stereocomplex between enantiomeric poly(l‐lactide) (l‐PLA) and poly(d‐lactide), crystallites formed as a result of stereocomplexation, equimolar l‐ and d‐lactide unit sequences are packed side by side. The stereocomplex exhibits a melting temperature higher by about 50 °C than that of each homopolymer. In this study, we attempt to obtain further insight into the stereocomplex‐induced surface structure of enantiomeric PLA blend films. The design of the blend systems is based on principles of surface segregation of multicomponent polymeric systems with a low surface energy, triblock copolymer (l‐PLA‐b‐PDMS‐b‐l‐PLA) of l‐PLA and poly‐(dimethyl siloxane). (l‐PLA‐b‐PDMS‐b‐l‐PLA/l‐PLA) blend films showed the surface segregation of PDMS, regardless of blend composition while the surface composition of PDMS in the (l‐PLA‐b‐PDMS‐b‐l‐PLA/d‐PLA) blend films was strongly depended on blend composition or a degree of complexation. These results are likely due to strong interaction between d‐ and l‐lactide unit sequences, which prevents the surface segregation of PDMS.