Cavitation-Mediated Fracture Energy Dissipation in Polylactide at Rubbery Soybean Oil-Based Block Copolymer Interfaces Formed via Reactive Extrusion.

Here, we spearhead a new approach to biopolymer impact modification that demonstrates superior performance while maintaining greater than 99% compostability. Using soybean-based monomers, a virtually untapped resource in terms of commercial volume and overall cost, a series of hyperbranched block copolymers were synthesized and melt-processed with poly(l-lactide) (PLA) to yield impact resistant all-polymer composites. Although PLA impact modification has been treated extensively, to date, the only practical solutions have relied on non-compostable petroleum-based rubbers.

Polystyrene--Polydimethylsiloxane as a Potential Silica Substitute for Polysiloxane Reinforcement.

Here we report microphase-separated poly(styrene--dimethylsiloxane) (PS--PDMS) as a reinforcing filler in PDMS thermosets that overcomes the long-standing problem of aging in the processing of silica-reinforced silicone. Surprisingly, PS--PDMS reinforced composites display comparable mechanical performance to silica-modified analogs, even though the modulus of PS is much smaller than that of silica and there is no evidence of percolation with respect to the rigid PS domains. We have found that a few unique characteristics contribute to the reinforcing performance of PS--PDMS.

Gel Point Suppression in RAFT Polymerization of Pure Acrylic Cross-Linker Derived from Soybean Oil.

Here we report the reversible addition-fragmentation chain transfer (RAFT) polymerization of acrylated epoxidized soybean oil (AESO), a cross-linker molecule, to high conversion (>50%) and molecular weight (>100 kDa) without macrogelation. Surprisingly, gelation is suppressed in this system far beyond the expectations predicated both on Flory-Stockmeyer theory and multiple other studies of RAFT polymerization featuring cross-linking moieties. By varying AESO and initiator concentrations, we show how intra- versus intermolecular cross-linking compete, yielding a trade-off between the degree of intramolecular linkages and conversion at gel point.

Combining Metabolic Engineering and Electrocatalysis: Application to the Production of Polyamides from Sugar.

Biorefineries aim to convert biomass into a spectrum of products ranging from biofuels to specialty chemicals. To achieve economically sustainable conversion, it is crucial to streamline the catalytic and downstream processing steps. In this work, a route that combines bio- and electrocatalysis to convert glucose into bio-based unsaturated nylon-6,6 is reported.

The battle for the "green" polymer. Different approaches for biopolymer synthesis: bioadvantaged vs. bioreplacement.

Biopolymers have been used throughout history; however, in the last two centuries they have seen a decrease in their utilization as the proliferation of inexpensive and mass-produced materials from petrochemical feedstocks quickly became better-suited to meeting society's needs. In recent years, high petroleum prices and the concern of society to adopt greener and cleaner products has led to an increased interest in biorenewable polymers and the use of sustainable technologies to produce them. Industrial and academic researchers alike have targeted several routes for producing these renewable materials.