title: Miscibility evaluation of poly(L-lactic acid)/poly(lactic acid-co-lysine) blends.
abstract: BACKGROUND
  The amorphous poly(lactic acid-co-lysine) (PLL) with hydrophilic reactive groups was synthesized by the condensing copolymerization and the blending miscibility of poly(L-lactic acid) (PLLA) and PLL was investigated.
  
  
  METHODS
  The miscibility of PLLA and PLL was evaluated by analyzing the thermal properties, crystallization behaviors, crystal morphologies and mechanical properties of the PLLA/PLL blends.
  
  
  RESULTS
  The results indicated that amorphous PLL changed the crystallization behaviors and thermal properties of PLLA, decreasing the crystallinity of PLLA in the blends. The amorphous PLL molecule chains in PLLA/PLL blends were able to enter into the lamellars of PLLA spherulites and affect the crystallization behaviors of PLLA, resulting in imperfect, spherulite structures of PLLA. The formation of hydrogen bonds between PLLA molecular chains and PLL molecular chains enabled partial compatibility in this blend system.
  
  
  CONCLUSIONS
  The existence of PLL improved the hydrophility of PLLA/PLL blends, led to a higher content of PLL in the PLLA/PLL blend system, and better hydrophilic properties of the blend system. The PLL was partially miscible with the PLLA, and the PLLA/PLL blend with 10 wt% PLL had improved tensile properties.
authors.affiliation: School of Natural and Applied Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi - PR China.
authors.forename: Junyan
authors.initials: J
authors.lastname: Yao
authors.affiliation: School of Natural and Applied Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi - PR China.
authors.forename: Shijie
authors.initials: S
authors.lastname: Zhang
authors.affiliation: School of Natural and Applied Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi - PR China.
authors.forename: Wudan
authors.initials: W
authors.lastname: Li
authors.affiliation: School of Natural and Applied Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi - PR China.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Li
mesh_terms: D011091:Polyesters / Q000737:chemistry*; D011107:Polylysine / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*
chemical_list: C106382:PLAL-lysine; D011091:Polyesters; D011108:Polymers; D011107:Polylysine; C033616:poly(lactide)