Search for: All records

Star block (ABC)4 terpolymers consisting of a rubbery poly(γ-methyl-ε-caprolactone) (PγMCL) (C) core and hard poly(l-lactide) (PLLA) (B) and poly(d-lactide) (PDLA) (A) end-blocks with varying PDLA to PLLA block ratios were explored as high-performance, sustainable, aliphatic polyester thermoplastic elastomers (APTPEs). The stereocomplexation of the PDLA/PLLA blocks within the hard domains provided the APTPEs with enhanced thermal stability and an increased resistance to permanent deformation compared to nonstereocomplex analogs. Variations in the PDLA:PLLA block ratio yielded tunable mechanical properties likely due to differences in the extent and location of stereocomplex crystallite formation as a result of architectural constraints. This work highlights the improvements in mechanical performance due to stereocomplexation within the hard domains of these APTPEs and the tunable nature of the hard domains to significantly impact material properties, furthering the development of sustainable materials that are competitive with current industry standard materials. 

Degradable epoxy-amine thermosets derived from cyclic-ketal monomers offer robust performance and facile end-of-use processing, enabling recovery of diketone building blocks and pristine carbon fiber from fiber reinforced polymer composites. 

Abstract Amphiphilic graft copolymers were prepared via a grafting through approach to yield materials with a hydrophilic backbone and hydrophobic arms. The thermally responsive macromonomers were designed to contain a Diels–Alder adduct such that cyclo‐reversion would cleave the arms from the backbone thus altering polymer topology, composition and solubility. The macromonomers were prepared via light‐inducted atom transfer radical polymerization followed by post‐polymerization modification to install a polymerizable functionality. Next, free radical polymerization was employed to yield thermally responsive amphiphilic graft copolymers, whose solution state characteristics were extensively characterized by UV/Vis spectroscopy and fluorimetry. Due to the amphiphilic nature of the graft copolymer, some unexpected results occurred because of aggregation and solubility limitations. Furthermore, it was discovered that poly(N‐isopropyl acrylamide) exhibited distinct and unique aggregation properties by itself.