International audienceFree radical polymerization of styrene was monitored in situ by combining Raman spectroscopy to other experimental techniques (gravimetry and rheology). Three different processes were investigated: bulk, emulsion and miniemulsion polymerization. A complete analysis of the evolution of Raman spectrum during the course of reaction showed that a lot of information about molecular dynamics could be extracted and related to chemical phenomena. In addition, we report for the first time the coupling of Raman spectroscopy to a rheometer in order to monitor styrene bulk polymerization both at the scale of chemical bonds and at the scale of macroscopic phenomena (viscosity variation)

The use of sequence‐defined polymers is an interesting emerging solution for materials identification and traceability. Indeed, a very large amount of identification sequences can be created using a limited alphabet of coded monomers. However, in all reported studies, sequence‐defined taggants are usually included in a host material by noncovalent adsorption or entrapment, which may lead to leakage, aggregation, or degradation. To avoid these problems, sequence‐defined polymers are covalently attached in the present work to the mesh of model materials, namely acrylamide hydrogels. To do so, sequence‐coded polyurethanes containing a disulfide linker and a terminal methacrylamide moiety are synthesized by stepwise solid‐phase synthesis. These methacrylamide macromonomers are afterward copolymerized with acrylamide and bisacrylamide in order to achieve cross‐linked hydrogels containing covalently‐bound polyurethane taggants. It is shown herein that these taggants can be selectively detached from the hydrogel mesh by reactive desorption electrospray ionization. Using dithiothreitol the disulfide linker that links the taggant to the gel can be selectively cleaved. Ultimately, the released taggants can be decoded by tandem mass spectrometry.

Thermal decomposition course of copper acetate monohydrate was monitored by combining diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) coupled with µ gas chromatography-mass spectrometry (µGC-MS) with other analytical techniques (thermogravimetry analysis and in situ X-ray diffraction). Non-isothermal kinetic was examined in air and Ar.A complete analysis of the evolution of infrared spectra matched with crystalline phase transition data during the course of reaction allows access to significant and accurate information about molecular dynamics. While thermogravimetry gives broad conclusion about two steps reaction (dehydration and decarboxylation), in line approach (in situ X-ray and in situ DRIFT coupled to µGC-MS) is proposed as an example of a new robust and forward-looking analysis. While decomposition mechanism of copper acetate monohydrate is still not well elucidated yet previously, the present in-line characterization results lead to accurate data making the corresponding mechanism explicit. techniques able to analyze data about different reaction media: powder, solid, liquid and gases. Two strategies could be proposed: continuous sampling coupled with fast analytical technique on one hand and in situ spectroscopic analysis on the other hand. Both approaches are complementary.Metal carboxylates are useful reagents particularly for organic synthesis [3] and applied in several fields of research as solid-state, surface chemistry and catalysis [3] [4] [5] [6]. The thermal decomposition of metal carboxylates is a feasible route to synthesize metal nanoparticles suitable for catalytic purposes [7] [8]