Isothermal Crystallization Process of Poly(l-lactic acid)/Poly(d-lactic acid) Blends after Rapid Cooling from the Melt

We observed the crystallization process in poly(l-lactic acid) (PLLA) and poly(d-lactic acid) (PDLA) blends using in situ simultaneous small- and wide-angle X-ray scattering measurements with a high-speed temperature control cell. In situ X-ray scattering measurements revealed that density fluctuations larger than the long spacing periods grew during crystallization above 130 °C. In particular, the time evolution of the density fluctuations has a strong dependence on the crystallization temperature. The density fluctuations will promote the crystal nucleation and growth processes of the stereocomplex and increase with increasing crystallization temperature, which is strongly correlated with the complexation of PLLA and PDLA chains. On the other hand, below 120 °C, the kinetics of stereocomplex formation might be hindered by the decreased mobility, and no density fluctuations were observed in the case of homo crystal growth of PLLA or PDLA.

[1]  Hideto Tsuji,et al.  Poly(lactide) stereocomplexes: formation, structure, properties, degradation, and applications. , 2005, Macromolecular bioscience.

[2]  Hiroshi Ito,et al.  Shear-induced conformational fluctuations of polystyrene probed by 2D infrared microspectroscopy , 2012 .

[3]  A. Sakai,et al.  Nucleating agent for poly(L‐lactic acid)—An optimization of chemical structure of hydrazide compound for advanced nucleation ability , 2007 .

[4]  Y. Ikada,et al.  Stereocomplex formation between enantiomeric poly(lactic acid). VIII. Complex fibers spun from mixed solution of poly(D‐lactic acid) and poly(L‐lactic acid) , 1994 .

[5]  Wilson C. K. Poon,et al.  Spinodal-assisted crystallization in polymer melts , 1998, cond-mat/9806024.

[6]  H. Tsuji.  Poly(lactic acid) stereocomplexes: A decade of progress. , 2016, Advanced drug delivery reviews.

[7]  C. Han,et al.  Fluctuation-Assisted Crystallization: In a Simultaneous Phase Separation and Crystallization Polyolefin Blend System , 2005 .

[8]  T. Iwata,et al.  Crystal structure and biodegradation of aliphatic polyester crystals , 1999 .

[9]  D. Grijpma,et al.  Crosslinked poly(l-lactide) and poly(ε-caprolactone) , 1996 .

[10]  N. Yoshie,et al.  Higher-order structures and mechanical properties of stereocomplex-type poly(lactic acid) melt spun fibers , 2006 .

[11]  Yoshito Ikada,et al.  Stereocomplex formation between enantiomeric poly(lactides) , 1987 .

[12]  Y. Kimura,et al.  Stereocomplexed polylactides (Neo-PLA) as high-performance bio-based polymers: their formation, properties, and application , 2006 .

[13]  M. Imai,et al.  Spinodal crystallization of polymers: Crystallization from the unstable melt , 2005 .

[14]  Y. Kimura.  Molecular, Structural, and Material Design of Bio-Based Polymers , 2009 .

[15]  K. Koyama,et al.  Effect of type of peroxide on cross-linking of poly(l-lactide) , 2008 .

[16]  Kazuki Fukushima,et al.  Controlled crystal nucleation in the melt-crystallization of poly(l-lactide) and poly(l-lactide)/poly(d-lactide) stereocomplex , 2003 .

[17]  Dujing Wang,et al.  Interplay between two phase transitions: crystallization and liquid-liquid phase separation in a polyolefin blend. , 2006, The Journal of chemical physics.

[18]  B. Lotz.  Single Crystals of the Frustrated β-Phase and Genesis of the Disordered α'-Phase of Poly(l-lactic acid). , 2015, ACS macro letters.

[19]  Y. Ikada,et al.  Crystal structure of stereocomplex of poly(L-lactide) and poly(D-lactide) , 1991 .

[20]  Masatoshi Matsuda,et al.  Crystallization and Melting Behavior of Poly (l-lactic Acid) , 2007 .

[21]  P. Olmsted,et al.  Early Stages of Crystallization in Isotactic Polypropylene , 2003 .

[22]  K. Nishida,et al.  In situ observations of the mesophase formation of isotactic polypropylene—A fast time-resolved X-ray diffraction study , 2012 .

[23]  Kanaya,et al.  Further evidence of spinodal decomposition during the induction period of polymer crystallization: time-resolved small-angle x-ray scattering prior to crystallization of poly(ethylene naphthalate) , 2000, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[24]  A. Su,et al.  Extensive Development of Precursory Helical Pairs Prior to Formation of Stereocomplex Crystals in Racemic Polylactide Melt Mixture , 2012 .

[25]  Y. Ikada,et al.  Epitaxial crystallization and crystalline polymorphism of polylactides , 2000 .

[26]  Y. Ikada,et al.  Biodegradable polyesters for medical and ecological applications , 2000 .

[27]  K. Tashiro,et al.  Crystal structure and disorder in Poly(l-lactic acid) δ form (α′ form) and the phase transition mechanism to the ordered α form , 2011 .

[28]  S. Saha,et al.  Isothermal and non-isothermal crystallization behavior of poly(l-lactic acid): Effects of stereocomplex as nucleating agent: [Polymer 47 (2006) 3826-3837] , 2006 .

[29]  H. Tsuji,et al.  Synchronous and separate homo-crystallization of enantiomeric poly(l-lactic acid)/poly(d-lactic acid) blends , 2012 .

[30]  R. Inoue,et al.  Precursor of Shish-Kebab in Atactic Polystyrene/Isotactic Polystyrene Blend above Nominal Melting Temperature , 2012 .

[31]  Y. Ikada,et al.  Stereocomplex formation between enantiomeric poly(lactic acids). 9. Stereocomplexation from the melt , 1993 .

[32]  J. Schawe.  Analysis of non-isothermal crystallization during cooling and reorganization during heating of isotactic polypropylene by fast scanning DSC , 2015 .

[33]  Masatoshi Matsuda,et al.  Effect of Polylactide Stereocomplex on the Crystallization Behavior of Poly(l-lactic acid) , 2009 .

[34]  C. Schick,et al.  Melting of Conformationally Disordered Crystals (α′-Phase) of Poly(l-lactic acid) , 2014 .

[35]  K. Kimura,et al.  Formation and morphology of “shish-like” fibril crystals of aliphatic polyesters from the sheared melt , 2010 .

[36]  H. Tsuji,et al.  Precursors in stereo‐complex crystals of poly(L‐lactic acid)/poly(D‐lactic acid) blends under shear flow , 2014 .

[37]  T. Kawai,et al.  Mesomorphic phase formation of plasticized poly(l‐lactic acid) , 2014 .

[38]  Y. Ikada,et al.  Stereocomplex formation between enantiomeric poly(lactic acid)s. 3. Calorimetric studies on blend films cast from dilute solution , 1991 .

[39]  K. Nishida,et al.  Spinodal patterns indicating unstable regime of polymer crystallization , 2004 .