Synthesis and Physical Properties of Thiol–Ene Networks Utilizing Plant-Derived Phenolic Acids

Abstract

Elastomeric polymer films synthesized through thiol−ene chemistry, suitable in applications as coatings and adhesives due to their ease of preparation and superior physical properties, are traditionally derived from petroleum sources. Of recent interest is the exploration of sustainable alternatives for the precursors to these materials. Here, we report the synthesis of thiol−ene networks through the photoinitiated reaction between allylated plant-based phenolic acids (salicylic acid and 4hydroxybenzoic acid) and a multifunctional thiol, followed by isothermal annealing. Plant-sourced phenolic acids offer many advantages as biorenewable monomers: their rigid aromatic rings are expected to provide mechanical strength to the resulting polymers and the presence of multiple hydroxyl and carboxyl groups leads to ease of functionalization. Both phenolic acids produced networks with high degrees of homogeneity and few defects, as evidenced by narrow glass transitions and consistency of their tensile behavior with the ideal elastomer model at low-to-moderate strains. The 4-hydroxybenzoic acid based network, which had a higher cross-link density, exhibited a higher glass transition temperature, modulus, tensile strength, and elongation at break as compared to the salicylic acid based network. This work develops fundamental relationships between the molecular structure of the phenolic acids and the physical properties of the resulting networks.

Thermal, mechanical and conductive properties of imidazolium-containing thiol-ene poly(ionic liquid) networks

“…The UV curing of thiol-ene networks was conducted at various thiol:ene molar ratios (1.0:1.0, 1.0:1.5, 1.0:2.0, 1.0:2.5, 1.0:3.0) following previously published procedures [6,48,49].…”

Dendrite Suppression by Synergistic Combination of Solid Polymer Electrolyte Crosslinked with Natural Terpenes and Lithium‐Powder Anode for Lithium‐Metal Batteries

“…The reaction between the thiol group of BPT and allyl groups of allyl PEO and terpenes to form SPEs was confirmed by FTIR spectra as shown in Figure S8. The thiol peak of BPT at 2565 cm −1 is not observed for all SPEs after the crosslinking reaction, indicating that a crosslinked polymer network is formed …”

Synthesis and Properties of Networks Based on Thiol‐ene Chemistry Using a CO2‐Based δ‐Lactone

“…Small or macromolecules functionalized with vinyl groups are an integral part of this chemistry. Many examples reported the thiol‐ene networks synthesis from olefinic substance such as biobased phenolic acid derivatives, isosorbide derivatives, spiroacetal alkenes, and unsaturated polyethercarbonates . The CO 2 ‐based monomer EVL containing two vinyl groups is a good candidate for thiol‐ene networks.…”