Stereocomplex poly(lactic acid) nanoparticles crystallized through nanoporous membranes and application as nucleating agent

Abstract

Stereocomplex crystallization of poly(l-lactic acid) (PLLA) and poly(d-lactic acid) (PDLA) was performed by flowing their blended solution through nano-channels of porous membranes.

Influence of poly(lactide) stereocomplexes as nucleating agents on the crystallization behavior of poly(lactide)s

“…27 In another study, PLLA/PDLA nanoparticles were reported to contain alpha-type crystals. 38 Aer annealing, the molten alphatype crystals were cold crystallized to form pure SC-type nanoparticles, which served as nucleating agents for PLLA matrix crystallization and signicantly shortened the crystallization time of the pure PLLA matrix. For example, when a PLLA lm was cooled from the molten state to induce non-isothermal crystallization, the addition of 1% PDLA effectively shortened the PLLA crystallization time.…”

Nanomaterial Preparation by Extrusion through Nanoporous Membranes

“…This approach offers promising potential for scale‐up production of biomineralized nanomaterials. This precipitation extrusion method has been further extended for preparing composite nanomaterials from other biomaterials including fibronectin, elastin, hyaluronan, and PLA . For example, Raoufi et al reported the use of precipitation extrusion to prepare a variety of biopolymer blended nanofibers with an AAO membrane .…”

“…They blended poly(L‐lactic acid) and poly( d ‐lactic acid) in chloroform as feed solution and extruded it through 100 nm PCTE or AAO membrane into a methanol receiver solution. Owing to the insolubility of PLA in methanol, stereocomplex nanoparticles were precipitated . Interestingly, Powell et al observed the phenomenon of transient precipitation and dissolution process of calcium hydrogen phosphate nanoparticles inside a conical‐shaped nanopore of a PET membrane .…”

“…Precipitation extrusion is a recently developed nanoporous membrane extrusion method for one‐step synthesis of nanoparticles and nanofibers . In a typical precipitation extrusion procedure ( Figure A), a feed solution containing dissolved solutes is forced through a nanoporous membrane to meet a receiver solution at the exits of the nanopores, in which the solutes are insoluble.…”

Unique Transitions in Morphology and Characteristics of Porous Poly(Lactic Acid) Enantiomers

“…Therefore, utilizing stereocomplex would transform PLLA monoliths into a high‐performance porous material, which can be used in various fields mentioned above with no difficulty. Although formations of gel, particle, and porous surface using sc‐PLA have been studied previously, there has been no report so far that investigates a monolithic pure sc‐PLA. Moreover, a phase separation technique combined with setereocomplexation between enantiomeric polymers has not been developed until now despite the fact that a variety of monoliths are now mainly fabricated through phase separation because of its simplicity and processability.…”