Journal of Polymer Science Part B: Polymer Physics, Vol.49, No.19, 1397-1409, 2011
Crystallization and Stereocomplexation Behavior of Poly(D- and L-lactide)-b-Poly(N,N-dimethylamino-2-ethyl methacrylate) Block Copolymers
The thermal properties, crystallization, and morphology of amphiphilic poly(D-lactide)-b-poly(N,N-dimethylamino-2-ethyl methacrylate) (PDLA-b-PDMAEMA) and poly (L-lactide)-b-poly(N,N-dimethylamino-2-ethyl methacrylate) (PLLA-b-PDMAEMA) copolymers were studied and compared to those of the corresponding poly(lactide) homopolymers. Additionally, stereocomplexation of these copolymers was studied. The crystallization kinetics of the PLA blocks was retarded by the presence of the PDMAEMA block. The studied copolymers were found to be miscible in the melt and the glassy state. The Avrami theory was able to predict the entire crystallization range of the PLA isothermal overall crystallization. The melting points of PLDA/PLLA and PLA/PLA-b-PDMAEMA stereocomplexes were higher than those formed by copolymer mixtures. This indicates that the PDMAEMA block is influencing the stability of the stereocomplex structures. For the low molecular weight samples, the stereocomplexes particles exhibited a conventional disk-shape structure and, for high molecular weight samples, the particles displayed unusual star-like shape morphology. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1397-1409, 2011
Keywords:block copolymers;crystallization;crystallization in block copolymers;isothermal crystallization kinetics;poly(lactic acid) copolymers;stereocomplexes;stereospecific polymers