Structural Features of Polylactide Films Obtained from a Melt and Solution

The morphology and structure of polylactide film samples obtained from a melt and from a solution in chloroform are studied. The crystallization process of polylactide takes place under nonisothermal conditions. It is determined that the melting and crystallization points of the polylactide sample obtained from the solution are, respectively, 2 and 4°C lower than the sample obtained from the melt. Using optical polarization microscopy, it is shown that the sample obtained from the solution has a spherulite structure, while spherulites are not detected in the polylactide sample obtained from the melt. The X-ray diffraction patterns of the polylactide samples crystallized from the solution and melt are different. Well-defined reflexes characteristic of the crystalline modification of the α-form are recorded on the diffractogram of the sample obtained from the solution. The pressed polylactide sample has an initially X-ray amorphous structure, which partially transforms into a crystalline structure during annealing for 60 min at 90°C. X-ray diffraction analysis revealed differences in the degree of crystallinity over the thickness of the polylactide sample obtained from the solution.