RESUMO
A powerful variation of traditional radical thiol-yne reaction with diphenylacetylene (DPA)-based starting materials leading to the quantitative and selective formation of the corresponding vinyl sulfides is reported. A variety of different thiols are shown to undergo reaction with DPA and the influence of their structure on reactivity is studied. The results obtained from the model reactions are then used to guide the efficient synthesis of hyperbranched poly(vinyl sulfide) (hb-PVS) systems by employing a dithiol and a trialkyne in an A2 + B3 approach. The polymers obtained show excellent solubility in common organic solvents and exhibit high refractive indices (e.g., 1.70 at 589 nm). The combined ease of processability and potential for cross-linking make these materials very interesting for applications, such as coatings for optical devices. The selective mono-addition thiol-yne reaction on DPA serves not only as a synthetic method for the preparation of PVS but could also be applied to the general modification of acetylene-containing materials.
Assuntos
Acetileno/análogos & derivados , Alcinos/química , Polímeros/química , Compostos de Sulfidrila/química , Acetileno/química , Química Click , Refratometria , Solubilidade , Sulfetos/químicaRESUMO
Here, we report on the first example of crosslinking (CL) hyperbranched polyphenylene (hb-PPh) with a small molecule crosslinker 1,3,5-tris(azidomethyl)benzene (TAMB). It was successfully shown that CL of the hb-PPh/TAMB (9:1) film is possible either thermally or photochemically making use of fundamentally different reaction mechanisms. Starting from a model reaction to prove the feasibility of the thermal CL reaction, we went on to check both the thermal and the photochemical crosslinkability of micrometer thick films. IR spectroscopy was furthermore used to confirm the CL process. Finally, the thin film morphology of the films before and after CL was investigated by AFM, revealing that the surface morphology was unaffected by the CL processes.
