We report the structures of dispersible units, a most fundamental but minimal dispersible structural unit of a carbon black (CB) filler that is formed in two kinds of rubber (polyisoprene and styrene-butadiene random copolymer) matrices under a given processing condition. The results obtained from various small-angle scattering techniques showed that the CB aggregates, as observed after the sonification of a CB/toluene solution, were a spherical shape composed of approximately nine primary CB particles fused together. In the rubber matrices, the aggregates clustered into higher order structures defined in this work as the dispersible units, which are the fundamental structural elements (or the "lower cutoff structures") that build up a higher order mass-fractal structure. Furthermore, we found that the morphology of the dispersible units strongly depended on the rubber matrix, although the mass-fractal dimensions remained unchanged.
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http://dx.doi.org/10.1021/la051352s | DOI Listing |
Adv Mater
December 2024
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Shaanxi, 710049, China.
The direct photocatalytic conversion of CO and HO into high-value C chemicals holds great promise but remains challenging due to the intrinsic difficulty of C-C and C-C coupling processes and the lack of clarity regarding the underlying reaction mechanisms. Here, the design and synthesis of a Cu-ZnS photocatalyst featuring dispersed Cu single atoms are reported. These Cu single atoms are coordinated with S atoms, forming unique Cu-S-Zn active units with tunable charge distributions that interact favorably with surface-adsorbed intermediates.
View Article and Find Full Text PDFJ Appl Clin Med Phys
December 2024
Department of Diagnostic and Interventional Radiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.
Purpose: To quantitatively evaluate the performance of two types of recurrent neural networks (RNNs), long short-term memory (LSTM) and gated recurrent units (GRU), using Monte Carlo dropout (MCD) to predict pharmacokinetic (PK) parameters from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) data.
Methods: DCE-MRI data for simulation studies were synthesized using the extended Tofts model and a population-averaged arterial input function (AIF). The ranges of PK parameters for training the RNNs were determined from data of patients with brain tumors.
PLoS One
December 2024
Agriculture and Agri-Food Canada, Lethbridge, Alberta, Canada.
Introduced Phragmites (Phragmites australis australis (Cav.) Trin. Ex Steud.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy.
The elastic response of chromium-tanned leather was successfully improved by treatment with XSBR, a carboxylated styrene-butadiene copolymer. The carboxylic groups pending from a styrene-butadiene rubber (SBR) backbone were found to promote penetration of the aqueous polymer dispersion into the fibrous tanned leather and participated in pH-reversible physical crosslinking by H-bonding. The different penetrations of XSBR or SBR were investigated using a micro-FTIR cross-sectional analysis from the grain (outer) to the flesh (inner) side of 18 wt% elastomer-treated samples, based on the shaved leather weight.
View Article and Find Full Text PDFPolymers (Basel)
November 2024
División de Física Aplicada, Centro de Investigación Científica y Educación Superior de Ensenada, Ensenada 22860, Mexico.
A series of copolymers containing a thermo-responsive biocompatible first block of poly[di(ethylene glycol) methyl ether methacrylate)--(oligo(ethylene glycol) methyl ether methacrylate], P(DEGMA--OEGMA) were chain-extended to incorporate either poly(-isopropylacrylamide), PNIPAAm or poly(-isopropylacrylamide--butyl acrylate), P(NIPAAm-co-BA) as second thermo-responsive block using reversible addition-fragmentation chain transfer (RAFT) polymerization. P(DEGMA--OEGMA)--PNIPAAm copolymers showed two response temperatures at 33 and 43 °C in an aqueous solution forming stable aggregates at 37 °C. In contrast, P(DEGMA--OEGMA)--P(NIPAAm--BA) copolymers showed aggregation below room temperature due to the shift in response temperature provoked by the presence of hydrophobic butyl acrylate (BA) units, and shrinkage upon heating up to body temperature, while maintaining the second response temperature above 40 °C.
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