Influence of aliphatic polycarbonate middle block on mechanical and microstructural behaviour of triblock copolymers based on poly(l‐lactide) and polycarbonate

• Published in: Polymer international Vol. 68; no. 3; pp. 400 - 409
• Main Authors: Konwar, Debanga B, Satapathy, Bhabani K, Jacob, Josemon
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.03.2019; Wiley Subscription Services, Inc
• Subjects: Abscisic acid; Aliphatic compounds; aliphatic polycarbonate; Atomic force microscopy; Biodegradability; Block copolymers; Chains; Copolymers; Differential scanning calorimetry; Ductile-brittle transition; Dynamic mechanical analysis; Mechanical properties; Methylene; Microscopy; Morphology; Organic chemistry; poly(l‐lactide); Polycarbonate; ring‐opening polymerization; Scanning electron microscopy; Storage modulus; tensile testing; triblock copolymers; X-ray diffraction
• ISSN: 0959-8103; 1097-0126
• DOI: 10.1002/pi.5723

Three different ABA‐type triblock copolymers each containing biodegradable aliphatic polycarbonate as the middle block and poly(l‐lactide) as the outer blocks were synthesized and the influence of the methylene chain length of the aliphatic polycarbonate middle block on various properties of the triblock copolymers was evaluated. Differential scanning calorimetry and wide‐angle X‐ray diffraction studies revealed that the incorporation of the outer blocks reduced the crystallinity of the middle aliphatic polycarbonate block. Variation of methylene chain length of the middle block led to a change in morphology from spherical to cylindrical as evidenced from atomic force microscopy studies. In addition, the mechanical properties of the block copolymers showed semi‐ductile to quasi‐brittle behaviour depending upon the composition of the middle block which was also confirmed using scanning electron microscopy. Dynamic mechanical analysis of the triblock copolymers indicated that storage modulus increased with a decrease in methylene chain length. © 2018 Society of Chemical Industry This study demonstrates that by changing the aliphatic polycarbonate middle block of a triblock copolymer, the morphology and mechanical properties of the triblock copolymer can be tailored.