The crystallization behavior of poly(ethylene glycol) and poly(l‐lactide) block copolymer: Effects of block length of poly(ethylene glycol) and poly(l‐lactide). Issue 4 (26th April 2019)

• Record Type: Journal Article
• Authors: Wang, Liying; Feng, Congshu; Shao, Jun; Li, Gao; Hou, Haoqing
• Is Part Of: Polymer crystallization. Volume 2:Issue 4(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-04-26
• Subjects: block copolymer -- crystallinity -- melting point -- poly(ethylene glycol) -- poly(l‐lactide); Crystalline polymers -- Periodicals; Crystallization -- Periodicals; Polymers -- Periodicals; 668.9
• DOI: 10.1002/pcr2.10071
• Languages: English
• ISSNs: 2573-7619

Abstract

Abstract: A series of poly(ethylene glycol)‐poly(l ‐lactide) (PEG‐PLLA) di‐, and tri‐block copolymers that consisted of different lengths of PEG and PLLA blocks were synthesized, and the crystallization behavior of PEG and PLLA blocks were investigated. Results demonstrate that PEG and PLLA blocks interact with each other, and the crystallization and melting behaviors of copolymers are dependent on the composition of PEG and PLLA. The crystallization of PEG block is confined by the existence of PLLA block, the more fraction of PLLA, the greater restriction on PEG. However, this confinement is reduced after PEG with the larger molecular weight is incorporated into the copolymers. The PEG acts as a solvent, which reduces the viscosity and enhances the chain mobility of the PLLA. The melting temperature of PLLA block decreases when the PEG length is increasing or when the molecular weight of PLLA is decreasing. With the increase of the molecular weight of the PLLA block, the crystallinity of PLLA firstly increases and then decreases. For the copolymers with different structures and molecular weights of PEG blocks, the crystallinity and melting point of PLLA block exhibit different unique component dependence. Abstract : In the poly(ethylene glycol)‐poly(l ‐lactide) (PEG‐PLLA) di‐ and triblock copolymers, the PEG acted as a diluted solvent and improved the mobility of the PLLA block. The crystallinity of PLLA firstly increased and then decreased with the increase of molecular weights. In the copolymers with a lower molecular weight of PLLA, higher crystallinity of PLLA was observed with a lower molecular weight of the PEG block. However, this tendency was reversed in the copolymers with higher molecular weights (>40 kg/mol). The crystallinity of PLLA in these copolymers exhibited different component dependence.