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Many recent efforts towards sustainable polymer development use building blocks from renewable biomass feedstocks. However, issues arising from the processes used to extract starting materials from biomass are often overlooked despite the safety and environmental hazards associated with energy-intensive separation processes and solvent utilization. Here, we describe a holistic approach towards using green solvents and processes to synthesize polyester thermosets from birch bark, a waste product from the paper and pulp industry. Betulin, a diol with a pentacyclic ring structure, was extracted from the bark of silver birch trees via reflux boiling using green solvents available from biobased sources. Ethanol and 1:1 ethanol:ethyl acetate mixtures were effective solvents for extraction with additional selectivity achieved via antisolvent precipitation. Betulin-rich extracts containing 62.2-81.5 wt% betulin were produced and directly used to prepare polyester thermosets using one-pot, solventless polycondensations with 100% of the starting materials available from biomass feedstocks. The polymers prepared directly from extracts had comparable properties to those synthesized from pure betulin, suggesting that additional processing steps required to achieve higher purity betulin may not be warranted. Overall, we present an approach to polyester development from betulin-rich birch bark extracts which incorporate green chemistry and engineering principles from feedstock to product.
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Photonic Crystal Enhanced Fluorescence for Digital Resolution Biosensing
Photonic crystals are used to amplify the fluorescence emission and collection efficiency from quantum dots and plasmonic fluor nanoparticles to enable miRNA and proteins to be detected from plasma with single molecule precision, with simple 1-step assays.
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- Award ID(s):
- 1900277
- PAR ID:
- 10532033
- Publisher / Repository:
- IEEE
- Date Published:
- Format(s):
- Medium: X
- Location:
- Orlando, FL
- Sponsoring Org:
- National Science Foundation
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