Polylactide (PLA) is a fully biodegradable and recyclable plastic, produced from a bio‐derived monomer: it is a circular economy plastic. Its properties depend upon its stereochemistry and isotactic PLA shows superior thermal‐mechanical performances. Here, a new means to control tacticity by exploiting rotaxane conformational dynamism is described. Dynamic achiral [2]rotaxanes can show high isoselectivity (P
i
=0.8, 298 K) without requiring any chiral additives and enchain by a chain end control mechanism. The organocatalytic dynamic stereoselectivity is likely applicable to other small‐molecule and polymerization catalyses.
Sustainable plastics
sourced without virgin petrochemicals, that
are easily recyclable and with potential for degradation at end of
life, are urgently needed. Here, copolymersand blends meeting these
criteria are efficiently prepared using a single catalyst and existing
commercial monomers
l
-lactide, propylene oxide, and maleic
anhydride. The selective, one-reactor polymerization applies an industry-relevant
tin(II) catalyst. Tapered, miscible block polyesters are formed with
alkene groups which are postfunctionalized to modulate the polymer
glass transition temperature. The polymers are blended at desirable
low weight fractions (2 wt %) with commercial poly(
l
-lactide)
(PLLA), increasing toughness, and elongation at break without compromising
the elastic modulus, tensile strength, or thermal properties. The
selective polymerization catalysis, using commercial monomers and
catalyst, provides a straightforward means to improve bioplastics
performances.
Study of a series of phosphasalen indium alkoxide complexes reveals that the substitution pattern at the phosphorus atoms can deliver outstanding isoselectivity with high rates.
The first report on the use of dinuclear aluminum complexes supported by methylene-bridged phenoxy-imine ligands for the ring-opening polymerization of rac-lactide.
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