Dynamic stabilisation during the drainage of thin film polymer solutions

The drainage and rupture of polymer solutions was investigated using a dynamic thin film balance. The polymeric nature of the dissolved molecules leads to significant resistance to the deformation of...

Spatial and Temporal Distribution of Chemically Characterized Microplastics within the Protected Area of Pelagos Sanctuary (NW Mediterranean Sea): Focus on Natural and Urban Beaches

Data on the abundance and distribution of Anthropogenic Marine Debris (AMD) on the coastal areas of the northern Tyrrhenian coast are still scarce. The objective of this study is to characterize, in terms of size, color, morphology and polymeric nature, the Large Microplastics (LMPs), i.e., plastic objects within 1 and 5 mm, sampled on three beaches located within the coastal macro-area of the Pelagos Sanctuary, an international protected zone in the north-western Mediterranean. The beaches have similar morphological characteristics but different degrees of urbanization. LMPs were sampled seasonally for one year. The polymeric nature of a representative subsample of the collected LMPs was investigated using a portable Raman instrument, to assess the feasibility of in situ characterization. In this study, 26,486 items were sorted by typology (Expanded Polystyrene-EPS, fragments, and resin pellets), size, and for fragments and resin pellets, also by color and chemical nature. Statistical data on the quantity, density, type, spatial distribution, and seasonality of the sampled LMPs are presented. Differences in LMP abundance and composition were detected among sites. A seasonality trend emerges from our statistical analysis, depending on both LMP typology and urbanization degrees of the beaches. Our data do not show the existence of a relationship between the size of the investigated MPs and their color, while they suggest that the type of polymer influences the degree of fragmentation. This underlines the need to further investigate the mechanisms leading to the production and dispersion of MPs in coastal areas, taking into account both the urbanization of the beach, and therefore the possible sources of input, and the different types of MPs. Finally, a Raman portable instrument proved to be a valuable aid in performing in situ polymeric characterization of LMPs.

Investigation of the Process of Finishing of Carbon Fibers of Various Brands with Oligomers and Polymers of Various Chemical Structures

The article presents the results of work on the dressing of various continuous carbon fibers of a different structure with compounds of oligomeric and polymeric nature. Using gravimetry, optical and scanning electron microscopy methods, it was shown that the fixation of sizing substances on the surface of carbon fibers depends on the brand of carbon fiber, the method of chemical activation and the nature of the sizing agent. It has been shown that the studied coupling agents exhibit increased adhesion to carbon fiber of the brand TGN-2.

Diaqua(nitrato-κ2O,O′)bis(L-valine-κO)lead(II) nitrate at 296 K

The structure of the title complex, [Pb(NO3)(C5H11NO2)2(H2O)2]NO3, had been determined previously at 173 and 193 K, and is now reported at 296 K, in the same space group. The main difference with the low-temperature structures is that a methyl group of one valine ligand is clearly disordered over two positions, for which the occupancies converged to 0.56 (3) and 0.44 (3). Bond-length variations within the coordination sphere of PbIIas a function ofTare difficult to assess because uncertainties on these parameters are high. On the other hand, Pb...O distances above 2.9 Å cannot be assigned unambiguously to formal Pb—O bonds. As a consequence, the polymeric nature of the complex previously described at 173 K is uncertain, as well as the actual coordination number of PbII, and it is thus not possible to determine if the metal environment is holo- or hemidirected.

Synthese und Kristallstruktur von 2,4-Bis(methyIamino)-2-pentenium - chlorid [1] / Synthesis and Crystal Structure of 2,4- Bis(methylamino)-2-pentenium Chloride [1]

The vinamidinium chloride C7H15N2Cl (5) is obtained from the corresponding vinamidine C7H14N2 (4) and HCl; the X-ray structure reveals a polymeric nature consisting of w-shaped cations connected with the chloride ions by hydrogen bonds

Triorganozinn- und Triorganobleiderivate von N-Benzoyl- und N-Formylglycin / Triorganotin and Triorganolead Derivatives of N-Benzoyl-and N-Formylglycine

Triorganotin and -lead derivatives of X-benzoylglveine (BzGlyH) and N-formylglycine (ForGlyH), R3MBzGly and R3MForGly (M = Sn; R = Me, Ph. M = Pb; R = Ph) have been prepared from R3MOH and BzGlyH or ForGlyH, respectively. According to spectro­scopic data the Me3Sn groups are essentially planar; molecules of R3SnForGly are bridged by unidentate carboxylate groups and formyl-C = O groups in the solid state, while Ph3PbForGly and benzoylglycinates are bridged by bidentate carboxylate groups. NH does not coordinate to M. Pentacoordination and a polymeric nature in the solid state is also indicated by Mößbauer data of Me3SnForGly and Me3SnBzGly. In solution all compounds are monomeric.