Synthetic methods and structural characterization are reported for 11 novel ternary compounds with the general formula RE 6 Cd 23 T (RE = La-Gd; T = Sn, Sb, Pb, and Bi). Their crystal structures, as revealed by single-crystal and powder X-ray diffraction, are of the cubic Zr 6 Zn 23 Si structure type (cF120, Fm 3m, Z = 4), a filled version of the Th 6 Mn 23 system. No Cdcontaining rare-earth metal binaries are known to form with this structure, but the inclusion of small amounts of a third element allows the formation of the interstitially stabilized ternary structures. Temperature dependent dc magnetization measurements confirm local-moment magnetism due to RE 3+ ground states for Ce, Pr, and Nd.
Nanocomposite filler particles provide multiple routes to mechanically reinforce pressure-sensitive adhesives (PSAs), as their large surface area to volume ratios provide a means of effectively crosslinking multiple polymer chains. A major advancement could therefore be enabled by the design of a particle architecture that forms multiple physical and chemical interactions with the surrounding polymer matrix, while simultaneously ensuring particle dispersion and preventing particle aggregation. Understanding how such multivalent interactions between a nanoparticle crosslinking point and the PSA polymer affect material mechanical performance would provide both useful scientific knowledge on the mechanical structure−property relationships in polymer composites, as well as a new route to synthesizing useful PSA materials. Herein, we report the use of polymer-grafted nanoparticles (PGNPs) composed of poly(nbutyl acrylate-co-acrylic acid) chains grafted to SiO 2 nanoparticle (NP) surfaces to cohesively reinforce PSA films against shear stress without compromising their adhesive properties. The use of acrylic acid-decorated PGNPs allows for ionic crosslinking via metal salt coordination to be used in conjunction with physical entanglement, yielding 33% greater shear resistance and up to 3-fold longer holding times under static load. In addition, the effects of material parameters such as PGNP/crosslinker loading, polymer graft length, and core nanoparticle size on mechanical properties are also explored, providing insights into the use of PGNPs for the rational design of polymer composite-based PSAs.
Polymer nanocomposites are an important class of materials whose properties are generally tuned as a function of their composition. New opportunities for controlling these properties lie in manipulating the 3D organization of their nanofillers.
The ternary phase hexacerium tricosacadmium telluride, CeCdTe, was synthesized by a high-temperature reaction of the elements in sealed Nb ampoules and was structurally characterized by powder and single-crystal X-ray diffraction. The structure, established from single-crystal X-ray diffraction methods, is isopointal with the ZrZnSi structure type (Pearson symbol cF120, cubic space group Fm-3m), a filled version of the ThMn structure with the same space group and Pearson symbol cF116. Though no Cd-containing rare-earth metal binaries are known to form with this structure, it appears that the addition of small amounts of a p-block element allows the formation of such interstitially stabilized ternary compounds. Temperature-dependent direct current (dc) magnetization measurements suggest local-moment magnetism arising from the Ce ground state, with possible valence fluctuations at low temperature, inferred from the deviations from the Curie-Weiss law.
Synthesis and crystal structure determinations are reported for six quaternary phases with the general formula RE6MgxCd23–xPb [RE = La, Ce; 0.6(1) ≤ x ≤ 3.2(1)]. These compounds were prepared by high temperature reactions of the elements in sealed Nb tubes. As revealed by powder and single‐crystal X‐ray diffraction, their crystal structures are of the cubic Zr6Zn23Si system (cF120, Fm3m, Z = 4), itself an interstitially filled variant of the Th6Mn23 structure type. Rather than distributing equally across the entire Cd23 sub‐structure, Mg displayed a tendency to accumulate at specific sites (most notably 4a); charge differences between sites within the sub‐structure, as revealed by computational methods, are the likeliest explanation.
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