Crystallization and thermal properties of PLLA comb polymer

• Published in: Journal of polymer science. Part B, Polymer physics Vol. 46; no. 6; pp. 589 - 598
• Main Authors: Zhao, Chuanzhuang, Wu, Dongxia, Huang, Nan, Zhao, Hanying
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15.03.2008; Wiley
• Subjects: annealing; Applied sciences; biopolymers; crystal structure; crystal structures; crystallization; differential scanning calorimetry; Exact sciences and technology; melting; melting point; Organic polymers; Physicochemistry of polymers; polymerization; polymers; Properties and characterization; Structure, morphology and analysis; temperature; thermal properties; X-radiation; X-ray diffraction; Crystal form; Melting; Graft copolymer; Lactic acid copolymer; Hydroxyethyl methacrylate copolymer; Experimental study; annealing; crystal structures; Melt crystallization; Lamellar structure; Supramolecular structure; crystallization; Kinetics; biopolymers; Isothermal crystallization
• ISSN: 0887-6266; 1099-0488
• DOI: 10.1002/polb.21394

Poly(L-lactide) (PLLA) on poly(2-hydroxyethyl methacrylate) (PHEMA) backbone was prepared by a combination of atom transfer radical polymerization (ATRP) and ring-opening polymerization (ROP). The structure of the comb polymer was analyzed by wide angle X-ray diffraction (WAXD), small angle X-ray scattering (SAXS), and differential scanning calorimetry (DSC). WAXD result indicates that the comb polymer has α crystalline modification with a 10₃ helical conformation. Lamellar parameters of the crystalline structure were obtained by one-dimension correlation function (1DCF) calculated from SAXS results. The calculations show that the thickness of crystalline layer is controlled by annealing temperature and comb structure. DSC was applied to study kinetics of the crystallization and melting behavior. Two melting peaks on melting curves of the comb polymer at different crystallization temperature were detected, and the peak at higher temperature is attributed to the melt-recrystallization. The equilibrium melting temperature is found to be influenced by the comb structure. In this article the effects of the comb structure on Avrami exponent, equilibrium melting point and melting peak of the comb polymer were discussed.