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CO 2 ‐induced crystallization of polylactide and its self‐templating ‘stack of coins’ crystalline microstructure
Author(s) -
Sankarpandi Sabapathy,
Park Chul B.,
Ghosh Anup K.
Publication year - 2017
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.24431
Subject(s) - materials science , crystallization , microstructure , lamellar structure , biomineralization , amorphous solid , composite material , phase (matter) , crystallization of polymers , layer (electronics) , polymer , stacking , chemical engineering , crystallography , chemistry , organic chemistry , engineering , physics , nuclear magnetic resonance
Can we learn from biomineralization process of natural materials to fabricate a three‐dimensional (3D) thick laminate microstructure by stacking of two‐dimensional (2D) crystalline structure? By adopting this self‐organization principle of biomineralization process, a polymer is crystallized two‐dimensionally into a multi‐layered architecture. Herein, we demonstrate a 2D crystallization method of polylactide and its principle of self‐organization to develop the discontinuous laminate microstructures. We find that instead of building a multilayered morphology layer‐by‐layer, the lamellar microstructures can be built in one step by using self‐organization principle of 2D crystallization. The biopolymer PLA is compression molded, and the molded samples are crystallized by using supercritical CO 2 in a high pressure vessel . The CO 2 ‐induced crystallization has a unique diffusion‐controlled crystallization mechanism, which tends to produce a disc‐shape spherultic structure. From microscopy analysis, we observe that these 2D spherulites are self‐organizing in nature and form 3D thick laminate structures with integrated amorphous phase in between. The obtained discontinuous laminate microstructure is comparable to “stack of coins” structure and we report the biomimetic approach of crystallization process. Thus, our study shows an innovative approach to engineer the crystalline microstructure of PLA. POLYM. ENG. SCI., 57:365–373, 2017. © 2016 Society of Plastics Engineers