Blends of PLLA and PAL were prepared by solution-cast method using co-boiling reagents including chloroform and ethanol (93/7

V/V)

and the co-boiling temperature was about 60℃

which could avoid the phase splitting of PLLA and PAL caused by different evaporate speed of the two solvents or polymer asynchronous precipitation.Thus

PLLA/PAL blends were obtained with uniform dispersion.The thermal properties and morphologies of the blends were studied

and the miscibility of PLLA and PAL was evaluated by DSC and POM.Each PLLA/PAL blend has a single Tg

and each testedTg is closed to the calculated one according to Fox theory.Thus

the blends have homogeneous amorphous phase

and PAL and amorphous region of PLLA are miscible.In the blends

PLLA’s Tm was reduced by adding into PAL

and the melting blends were thermodynamically stable systems.Amorphous PAL showed obvious effect on the thermal properties and crystallization behaviours of PLLA in the blends

which indicated PLLA and PAL were compatible.PLLA in the blends exhibited faulty spherulites

lower melting points and lower crystallinity.The growth of PLLA spherulites was varied from homogeneous coring to heterogeneous coring in the presence of PAL.POM micrographs showed that PAL was among the lamellar crystals of PLLA spherulites

and changed the PLLA crystal shape to faulty spherulites.PAL had the retardarce action on the crystallization speed of PLLA melt

and caused PLLA spherulites to become imperfect.Because of the chain entwisting and hydrogen bond forming

the interactions between PLLA and PAL chains are strong.Thus

PLLA and PAL are miscible and form the blends with miscible structures.When PAL content was less than 20%

the tensile strength and break elongation were higher than those of pure PLLA

and the blend of 10% PAL content showed the best tensile properties.