Non-destructive detection and identification of plasticizers in PVC objects by means of machine learning-assisted Raman spectroscopy.

Vibrational spectroscopic techniques, such as Raman spectroscopy, as a non-destructive method combined with machine learning (ML), were successfully tested as a quick method of plasticizer identification in poly(vinyl chloride) - PVC objects in heritage collection. ML algorithms such as Convolutional Neural Network (CNN), Random Forest (RF), Support Vector Machines (SVM), and Linear Discriminant Analysis (LDA) were applied to the classification and identification of the most common plasticizers used in the case of PVC. The CNN model was able to successfully classify the five plasticizers under study from their Raman spectra with a high accuracy of (98%), whereas the highest accuracy (100%) was observed with the RF algorithm.

Intercalation of Ionic Liquids into LDH Structures for Microwave-Accelerated Polymerizations.

Microwave-accelerated ring-opening polymerization (ROP) of cyclic esters catalyzed by ionic liquid (IL) anions, intercalated into layered double hydroxides (LDHs), has been recently described as a fast and environmentally friendly synthetic way to prepare biodegradable polyester/LDH nanocomposites. However, to observe this synergistic catalytic effect between microwaves and IL anions and to achieve a homogeneous structure of the final polymer nanocomposite, the IL anions must be efficiently intercalated inside the LDH structure. Herein, we investigate the effects of various metal compositions of M/Al LDHs (M = Mg, Co, and Ca) and different LDH synthetic routes (one-step direct coprecipitation, two-step coprecipitation/anion exchange, and two-step urea/anion exchange) on the intercalation efficiency of trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate IL.

Explosive COVID-19 outbreak in a German nursing home and the possible role of the air ventilation system.

Background: Most COVID-19 outbreaks in nursing homes are explained by transmission of SARS-CoV-2 from nurses or visitors.

Methods And Results: We describe an outbreak with 64 of the 67 residents identified as COVID-19 cases within two weeks (34 in nursing block 1, 30 in nursing block 2), at least 32 of them had relevant symptoms of COVID-19. Thirteen of the residents' deaths were associated with COVID-19.

Insight into the aqueous Laponite® nanodispersions for self-assembled poly(itaconic acid) nanocomposite hydrogels: The effect of multivalent phosphate dispersants.

Hypothesis: We hypothesize, that physical network between Laponite® nanoparticles and high molecular weight polyelectrolyte formed by mixing of Laponite® nanodispersion (containing multivalent phosphate dispersant) and polyelectrolyte solution is strongly influenced by the type and content of dispersant, which forms electric double layer (EDL) closely to the Laponite® edges. Thus, optimum dispersant concentration is necessary to overcome clay-clay interactions (excellent clay delamination), but should not be exceeded, what would result in the EDL compression and weakening of attractions forming clay-polyelectrolyte network. Thus, deeper investigation of Laponite® nanodispersions is highly demanded since it would enable to better design the self-assembled clay-polyelectrolyte hydrogels.

Effects of Immobilized Ionic Liquid on Properties of Biodegradable Polycaprolactone/LDH Nanocomposites Prepared by In Situ Polymerization and Melt-Blending Techniques.

The high capacity of calcinated layered double hydroxides (LDH) to immobilize various active molecules together with their inherent gas/vapor impermeability make these nanoparticles highly promising to be applied as nanofillers for biodegradable polyester packaging. Herein, trihexyl(tetradecyl)phosphonium decanoate ionic liquid (IL) was immobilized on the surface of calcinated LDH. Thus, the synthesized nanoparticles were used for the preparation of polycaprolactone (PCL)/LDH nanocomposites.