Stereocomplex formation of poly(l-lactide)-poly(ε-caprolactone) multiblock copolymers with Poly(d-lactide)

• Published in: Polymer (Guilford) Vol. 123; pp. 73 - 80
• Main Authors: Jikei, Mitsutoshi, Yamadoi, Yuta, Suga, Takahiro, Matsumoto, Kazuya
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 11.08.2017; Elsevier BV
• Subjects: Biodegradability; Biodegradation; Block copolymers; Calorimetry; Chemical synthesis; Copolymerization; Copolymers; Deformation; Differential scanning calorimetry; Diffraction; Dynamic mechanical analysis; Dynamic stability; Elastomers; Elongation; Mechanical properties; Melting; Modulus of elasticity; Multiblock copolymer; Oligomers; Poly(L-lactide); Polycaprolactone; Polylactic acid; Stability analysis; Stereocomplex; Stereocomplexes; Studies; Temperature; Tensile properties; Thermal properties; Thermoplastic elastomers; X-ray diffraction; Thermal properties; Stereocomplex; Multiblock copolymer; Tensile properties
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2017.07.012

Stereocomplex formation is known to increase the melting temperature of poly(l-lactide) (PLLA). In this study, we investigate the stereocomplex formation of poly(l-lactide)-poly(ε-caprolactone) multiblock copolymers (PLLA-PCL MBCs) with poly(d-lactide) (PDLA). The stereocomplexed PLLA-PCL MBCs were readily synthesized by adding PDLA into PLLA-PCL MBCs solutions. X-ray diffraction and differential scanning calorimetry measurements indicate the preferential formation of stereocomplexes. Tensile moduli of PLLA-PCL MBCs increased after stereocomplex formation; however, they conserved their large elongation at break values even when the composition of hard segments (PLLA and PDLA) in the sample increased. The combination of high Young's modulus (>400 MPa) and large elongation (>400%) is high level reported for biodegradable thermoplastic elastomers. Dynamic mechanical analysis measurements suggest improved thermal-deformation stability in the stereocomplexes. Stereocomplex formation of PLLA-PCL random multiblock copolymers synthesized by the copolymerization of PLLA and PCL oligomers with PDLA also effectively increased the melting temperature and the Young's modulus. This simple strategy of adding PDLA into PLLA-segmented copolymers may be a useful method for the synthesis of any other stereocomplexed PLLA-segmented block copolymer. [Display omitted] •PLLA-PCL Multiblock Copolymers were stereocomplexed with PDLA oligomer.•X-ray diffraction and DSC measurements supported efficient stereocomplex formation.•Stereocomplex films showed high Young's modulus and large elongation at break.•PLLA-PCL random multiblock copolymers were also stereocomplexed with PDLA oligomer.