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A silicone rubber foam is prepared by introducing polydiborosiloxane (PDBS) into silicone rubber, and using expandable microspheres as blowing agents. The influences of the dual network structure with dynamic cross-linking network on the silicone rubber foam is characterized by the cell size, mechanical properties and impact resistance. The cell size increases from 77 to 93 [micro]m due to the introduction of a dynamic cross-linking network which reduces foaming resistance. The elongation at break elevates from 277% to 574%, and the yield strength gradually decreases. The dynamic cross-linking network also enhances the internal damping characteristic and energy absorption capacity of the foam. The impact resistance of silicone rubber foam is improved because of the synergistic effect of the dual network structure and the bubble structure. The research improves the performance of silicone rubber foam. KEYWORDS anti-impact, dynamic cross-linking, polydiborosiloxane, silicone rubber Highlights * The dual network structure to improve the mechanical properties. * Excellent cell is obtained using expandable microspheres as foaming agent. * The toughness and elongation are enhanced by regulating the molecular structure. * The dual network structure ameliorates the damping and energy absorption. * Dynamic cross-link and expandable microspheres increase the impact resistance., 1 | INTRODUCTION Silicone rubber as a polymer elastomer is extensively used in various field due to its excellent thermal stability, (1) mechanical property, (2) biocompatibility, and radiation resisting property. [...]

AbstractThe S100 family proteins (S100s) participate in multiple stages of tumorigenesis and are considered to have potential value as biomarkers for detecting and predicting various cancers. But the role of S100s in lung adenocarcinoma (LUAD) prognosis is elusive. Transcriptional data of LUAD patients were retrieved from TCGA, and relevant literature was extensively reviewed to collect S100 genes. Differential gene expression analysis was performed on the LUAD data, followed by intersection analysis between the differentially expressed genes (DEGs) and S100 genes. Unsupervised consensus clustering analysis identified two clusters. Significant variations in overall survival between the two clusters were shown by Kaplan-Meier analysis. DEGs between the two clusters were analyzed using Lasso regression and univariate/multivariate Cox regression analysis, leading to construction of an 11-gene prognostic signature. The signature exhibited stable and accurate predictive capability in TCGA and GEO datasets. Subsequently, we observed distinct immune cell infiltration, immunotherapy response, and tumor mutation characteristics in high and low-risk groups. Finally, small molecular compounds targeting prognostic genes were screened using CellMiner database, and molecular docking confirmed the binding of AMG-176, Estramustine, and TAK-632 with prognostic genes. In conclusion, we generated a prognostic signature with robust and reliable predictive ability, which may provide guidance for prognosis and treatment of LUAD. [ABSTRACT FROM AUTHOR]

Though hindered phenol/polymer-based hybrids show great potential in damping fields, the application of the materials is limited due to the irregular migration and self-aggregation of hindered phenol. To overcome this problem, 8-layered polyurethane (TPU)-polyvinyl acetate (PVAc) with varying phenol content in the polyurethane layer was fabricated using coextrusion. The distinct multilayer microstructure was first observed through the scanning electron microscopy. Subsequent molecular dynamics simulation revealed a directional migration of the hindered phenol to the interface without self-aggregation, existence of intermolecular hydrogen bonds between TPU (or PVAc) and hindered phenol, promoted diffusion of TPU and PVAc layers and reduced free volume. Then, the structure evolution was associated to the enhanced damping properties of the multilayer hybrids by the combination of the results of dynamic mechanical analysis. KEYWORDS coextrusion, damping mechanism, multilayer, stable hindered phenol, structure evolution, 1 | INTRODUCTION For polymeric materials, the physical properties are greatly affected by hydrogen bonds (H-bonds). [1-6] It has been found that the melting temperature and the glass transition temperature [...]

A series of microcellular silicone rubber foams were prepared by supercritical carbon dioxide (scC[O.sub.2]). The effect of reinforcing agent (silica) on the rheological behavior, cellular morphology and nucleation of silicone rubber composites was investigated. The results show that the silica not only acts as reinforcing agent but also plays an important role in the cellular nucleation. When the content of silica increases from 40 phr to 70 phr, the range of the calculated surface tension of silicon rubber composites/ scC[O.sub.2] ([[gamma].sub.mix]) and radius of the critical nucleus ([r.sup.*]) are 158.95~1,092.74 nN/m and 14.45-99.34 nm, respectively. Meanwhile, aggregated silica has good heterogeneous nucleation as the diameter of aggregated silica particles is approximate to twice [r.sup.*]. The smallest cell diameter and the highest cell density of the silicone rubber foam can reach to 708 nm and 1.02 x [10.sup.11] cells/[cm.sup.3], which indicate that the silicone rubber nanofoams can be obtained by means of the supercritical foaming technology. POLYM. ENG. SCI., 59:5-14, 2019., INTRODUCTION Silicone rubber foam is a porous polymer elastic material which includes the characteristics of silicone rubbers and foam materials [1], It combines the excellent characteristics of silicone rubber material [...]

Toward data-driven wall-modeled large-eddy simulations of different wall-bounded turbulent flows, a wall model is learned in this work using the wall-resolved large-eddy simulation (WRLES) data of the flow over periodic hills (PH) and the law of the wall (LoW). The feedforward neural network (FNN) is employed to construct the model. The obtained FNN_PH-LoW model is successfully tested using the direct numerical simulation data of turbulent channel flows and the WRLES data of PH cases, and applied to turbulent channel flows for a wide range of Reynolds numbers. [ABSTRACT FROM AUTHOR]

The silicone rubber materials with soft and hard alternating multilayered structure were successfully fabricated by multilayer co-extrusion technique. The influence of alternate multilayer structure on the mechanical properties of silicone rubber was discussed. The regular and continuous multilayered structure was observed. Meanwhile, with the increase of the layer number, the tensile strength and elongation at break increased, and the compressibility was also obviously improved. Compared with that of 3-layer of silicone rubber, the elongation at break and tensile strength of 129-layer silicone rubber were increased by 42.5 % and 70.2 %, respectively. [ABSTRACT FROM AUTHOR]

A series of microcellular silicone rubber/silica/polyhedral oligomeric silsesquioxane (POSS) foams were prepared by supercritical carbon dioxide. The effect of POSS particles on the rheological behavior, vulcanizing, and cellular morphology of the composites was investigated. The results showed that the POSS grafted carboxylic acid group can improve the matrix strength of silicone rubber. POSS grafted carboxylic acid group act as inhibiting agent in the vulcanizing process. POSS particles play an important role in the microcellular structure formation. When the POSS content was 2.0 wt%, the cell size and cell density can reach to 3.77 µm and 7.99 × 109 cell/cm3, respectively. [ABSTRACT FROM AUTHOR]

ABSTRACT The alternating multilayered damping composites, which were consisted of chlorinated butyl rubber (CIIR) layers and poly(vinyl chloride) (PVC) layers, were first prepared through multilayered coextrusion technology. The multilayered structure was controlled by adjusting the layer number or the thickness ratio of CIIR layer and PVC layer. The damping and flame-retardant properties of the CIIR/PVC multilayered damping composites were investigated by dynamic mechanical analysis, the limiting oxygen index, and thermogravimetric analyzer, respectively. The results showed that the effective damping temperature range was broadened with increasing the layer number, since multilayered structure resulted in partial overlap of the loss peaks of CIIR and PVC. Meanwhile, the flame-retardant properties of the multilayered composites were also enhanced with increasing the layer number. Less surface area of CIIR contacting oxygen in the confined burning space, rather than the formation of char residue, could effectively retard the combustion of the material. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41259. [ABSTRACT FROM AUTHOR]