Stereocomplexed polylactides (Neo‐PLA) as high‐performance bio‐based polymers: their formation, properties, and application

Abstract

Polymeric materials prepared from renewable natural resources are now being accepted as ''bio-based polymers'', because they are superior to the conventional petroleum-based polymers in reducing the emission of carbon dioxide. Among them, poly(L-lactide) (PLLA) prepared by fermentation and polymerization is paid an immediate attention. Although PLLA exhibits a broad range of physico-chemical properties, its thermal and mechanical properties are somewhat poorer for use as ordinary structural materials. For improving these inferior properties, a stereocomplex form consisting of PLLA and its enantiomer poly(D-lactide) (PDLA) has high potential because of showing high melting nature (230 • C). It can be formed by simple polymer blend of PLLA and PDLA or more easily with stereoblock polylactides (sb-PLA) which are PLLA/PDLA block copolymers. These novel PLA polymers, named ''Neo-PLA'', can provide a wide range of properties that have never be attained with single PLLA. Neo-PLA retains sustainability or bio-based nature, because both monomers L-and D-lactic acids are manufactured from starch by fermentation.

Preparation and properties of multi-branched poly(D-lactide) derived from polyglycidol and its stereocomplex blends

“…When the chain length of mbPDLAs increases, the value sharply increases, where an increase of 1 and 2 orders of magnitude is observed in mbPDLA201 and mbPDLA501, respectively. This reflects a formation of stronger interaction, i.e., hydrogen bonding, between the 2 stereoconstituents [2,47,48]. A sharp decrease in the values is observed when the structure melts.…”

“…Tin(II) octoate catalyst, Sn(Oct) 2 , was purchased from Wako (Japan). Glycidol was purchased from Aldrich (USA) and used as received.…”

“…Preparation, structures, properties, and applications of this structure have been extensively studied [17,[23][24][25][26][27]. Formation of stereocomplex structure is usually accompanied by homo-crystallization, predominantly when high molecular weight PLAs are employed [2,10]. A complete stereocomplexation, without homo-crystallite, is obtained from an equimolar mixture of sufficiently-low molecular weight PLLA and PDLA.…”

Crystallization and hydrolytic/thermal degradation of a novel stereocomplexationable blend of poly(L-2-hydroxybutyrate) and poly(D-2-hydroxybutyrate)

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Stereocomplexation between PLLA and its enantiomer poly(D-lactide) (that is, poly(D-lactic acid) or PDLA) can yield biodegradable materials having superior mechanical performance and resistance to hydrolytic and thermal degradation relative to pure PLLA and PDLA. [16][17][18][19][20] Poly(2-hydroxybutyrate) (that is, poly(2-hydroxybutanoic acid) or P(2HB)) is a biodegradable polymer with the structure of a poly(lactide) (that is, poly(lactic acid) or PLA) in which methyl groups are substituted with ethyl groups.…”

Reactive Electrospinning of Stereoblock Polylactides Prepared via Spontaneous Diels-Alder Coupling of Bis Maleimide-terminated Poly-L-lactide and Bis Furan-terminated Poly-D-lactide

“…However, the long processing time in the crystallization-induced mixing and the low polymer concentration used in the electrospinning may retard the processabilities. Recently, we demonstrated that stereoblock-type PLAs (sb-PLA) consisting of PLLA and PDLA sequences can easily form the sc crystals with little hc crystallization [13][14][15][16][17][18][19][20][21], because they ought to have a mixing state of the enantiomeric PLLA and PDLA blocks in molecular level. Furthermore, we showed that the sbPLAs can efficiently be formed by spontaneous DielsAlder coupling of PLLA and PDLA prepolymers having dienophile (maleimide) and diene (anthracene) terminals, respectively [21].…”