Mechanical, thermal and transport properties of nitrile rubber (NBR)—nanoclay composites

The article describes the properties of nitrile rubber (NBR)??nanoclay composites prepared by a two-step method. viz. preparation of a 3:1 [by weight] masterbatch of NBR and nanoclay followed by compounding on a two roll mill and molding at 150?°C and 20?MPa pressure. The tensile strength, elongation at break, modulus, storage modulus (E??) and loss modulus (E??) increased with the nanofiller content, reached the maximum value at 5 phr and decreased thereafter. The solvent uptake, diffusion, sorption and permeation constants decreased with nanoclay content with the minimum value at 5 phr nanoclay. The mechanism of solvent diffusion through the nanocomposites was found to be Fickian. Thermodynamic constants such as enthalpy and activation energy were also evaluated. The dependence of various properties on nanoclay content was correlated to the morphology of the nanocomposites. supported by morphological analysis.     

Mechanical, thermal and transport properties of nitrile rubber (NBR)—nanoclay composites

The article describes the properties of nitrile rubber (NBR)—nanoclay composites prepared by a two-step method. viz. preparation of a 3:1 [by weight] masterbatch of NBR and nanoclay followed by compounding on a two roll mill and molding at 150 °C and 20 MPa pressure. The tensile strength, elongation at break, modulus, storage modulus (E’) and loss modulus (E”) increased with the nanofiller content, reached the maximum value at 5 phr and decreased thereafter. The solvent uptake, diffusion, sorption and permeation constants decreased with nanoclay content with the minimum value at 5 phr nanoclay. The mechanism of solvent diffusion through the nanocomposites was found to be Fickian. Thermodynamic constants such as enthalpy and activation energy were also evaluated. The dependence of various properties on nanoclay content was correlated to the morphology of the nanocomposites. supported by morphological analysis.     

Toughening of vinylester–urethane hybrid resins by functional liquid nitrile rubbers and hyperbranched polymers

Liquid nitrile rubbers with vinyl (VTBN), carboxyl (CTBN) and epoxy (ETBN) and hyperbranched polyesters with vinyl (VHBP) and epoxy (EHBP) functionalities were added in 10 wt% to a bisphenol-A based vinylester–urethane hybrid resin (VEUH) for its toughening. The fracture energy (G_c) was determined on compact tensile specimens at ambient temperature. High toughness improvement was achieved by adding ETBN and CTBN to VEUH. It was established that a change in the initial stoichiometry of OH/NCO may affect G_c.The combination of CTBN with other additives in 1:1 ratio yielded a synergistic effect with respect to G_c. Changes in G_c were explained by differences in the fracture mode based on fractographic inspection of the fracture surface of the specimens. It was shown the same G_c may be derived from completely different failure scenarios.     

The structure and dynamic properties of nitrile–butadiene rubber/poly(vinyl chloride)/hindered phenol crosslinked composites

In this article, a new nitrile–butadiene rubber (NBR) crosslinked composites containing poly(viny chloride) (PVC) and hindered phenol (AO-80 and AO-60) was successfully prepared by melt-blending procedure. Microstruture and dynamic mechanical properties of the composites were investigated using SEM, DSC, XRD, and DMTA. Most of hindered phenol was dissolved in the NBR/PVC matrix and formed a much fine dispersion. The results of DSC and DMTA showed that strong intermolecular interaction was formed between the hindered phenol and NBR/PVC matrix. The NBR/PVC/AO-80 crosslinked composites showed only one transition with higher glass transition temperature and higher tan δ value than the neat matrix, whereas for the NBR/PVC/AO-60 crosslinked composites, a new transition appeared above the glass transition temperature of matrix, which was associated with the intermolecular interaction between AO-60 and PVC component of the matrix. Both AO-80 and AO-60 in the crosslinked composites existed in amorphous form. Furthermore, the chemical crosslinking of composites resulted in better properties of the materials, e.g., considerable tensile strength and applied elastic reversion. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation of carbon nanotubes/hydrogenated nitrile rubber composite by ultrasonic technique

将低相对分子质量的液体氢化丁腈橡胶(HNBR)溶于丙酮溶剂中,加入碳纳米管,用超声波技术制备了液体HNBR与碳纳米管的复合母料,然后再与HNBR混炼、硫化,获得碳纳米管/HNBR复合材料.结果表明,碳纳米管在HNBR中分散性好,对HNBR有较好的增强性,但在后期机械加工中产生了断裂.     

Correlation of the morphology and thermooxidative degradation behavior of poly(ethylene terephthalate)–nitrile butadiene rubber–polycarbonate ternary blends

In this study, we prepared ternary poly(ethylene terephthalate) (PET)–nitrile butadiene rubber (NBR)–polycarbonate (PC) blends through a molten mixing procedure, and with a corotating extruder, we studied the morphology and thermodynamic properties of each purified polymer and the binary and ternary blends with different compositions. Dynamic mechanical analysis of both the PET–PC and PET–NBR samples showed individual loss peaks for each component, but in different ternary samples, the effects of different percentages of components (PC–PC and PET–NBR) were observed; this revealed changes in the loss peak locations. Individual loss peaks of PET and PC in the ternary PET–NBR–PC blends (81/9/10 and 63/30/7)—proof of the miscibility of the samples—were also observed in this study. The thermal properties of the samples were measured and examined with the thermogravimetric analysis and differential thermogravimetry testing methods. The activation energy and order of reaction values for the samples under an air atmosphere with single-rate methods of heating were studied. Finally, the relation between the type of morphology and the thermal degradation behavior was investigated. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47171.     

High shape-memory effect of hindered phenol/nitrile–butadiene rubber composites by forming hydrogen bonding

To widen the type and scope of use of shape memory polymers (SMPs), we added hindered phenol (AO-80) to nitrile–butadiene rubber (NBR) to gain a group of AO-80/NBR rubber composites. The glass transition temperature (T_g), structure, mechanical properties, and shape memory properties of the AO-80/NBR rubber composites were characterized. It was concluded that the dispersion of AO-80 in the NBR matrix was homogeneous and intra-molecular hydrogen bonds were formed between the hydroxyl groups ( OH) of AO-80 and the cyano groups ( CN) of NBR molecular chain. The dosage of AO-80 added could be changed to tune the T_g. AO-80/NBR rubber composites revealed outstanding shape fixity and shape recovery. The method for tuning the T_g of AO-80/NBR rubber composites will provide an idea for the fabrication and design of new SMPs. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48911.     

Characteristics and Application of Andalusite Material and Andalusite-Based Refractory

Andalusite material and Andalusite-based refractory are very popular in Europe and Japan, but its applications are restrained because of its low quality and misunderstanding in China. The paper introduced in detail the characteristics of andalusite material and andalusite-based refractory based on the authors‘ research work in recent years and on some references. Some information is illustrated clearly by figures and microstructure photographs. It is concluded the property of raw material and refractory is not determined by alumina content but by type and quantity of the impurities and microstructure.Mullitisation provide andalusite-based refractories more excellent macro and micro properties that guarantee itspopular application.     

vince and Shij

1前言据不完全统计,上个世纪90年代,全国曾有各种类型的立窑数量近万台,立窑水泥的年产量,约占我国水泥年总产量的80%以上。但是立窑生产带来的粉尘污染却十分严重,预计达千万吨之多,约占我国水泥行业粉尘年总排放量的90%。自国家经贸委发布在2000年以前,淘汰直径<2.2m的立窑和     

Economy and Business

<正> China Releases Tire Industry Policy The Ministry of Industry and Information Technology on October 11th released the tire industry policy to encourage the development of safe, energy-saving and environmental-friendly high-performance radialtires. The tires include giant OTR (off the road) tires, wide cross-section and flat passenger car radial tires and truck radial tire swith no inner tubes. By 2015, radial tires should be used for all passenger cars, and for 85% of light trucks and for 90% of heavy-duty trucks. China will focus on the development of radial tires for OTR, airplanes, and low-speed vehicles.     

Dynamic mechanical and acoustic properties comparison of CR and SBR

研究了氯丁橡胶(CR)和丁苯橡胶(SBR)的动态力学性能,计算了剪切波速率.结果表明,SBR的反声效果好,适合用做声障板材料.     

Fabrication and photoluminescence of γ-AlON:Sm and Yb

Transparent γ-AlON undoped and doped with one of eight rare earth elements were fabricated by hot pressing at 1850 °C. After characterizing the fundamental physical properties of sintered γ-AlON, the photoluminescence spectra of γ-AlON:Sm and γ-AlON:Yb were examined further because only these samples showed a color under visible light because of the absorbance of a certain wavelength. γ-AlON:Sm exhibited a red emission with emission peaks at 688, 701, and 729 nm, while γ-AlON:Yb exhibited a white emission due to the two broad emission peaks at 438 and 575 nm. γ-AlON:Yb revealed a possible application to UV-excited phosphor-converted white-light-emitting diodes because of its emission characteristics. The schematic crystal structure of the rare-earth-doped γ-AlON and the CIE chromaticity diagram were provided to understand the photoluminescence behavior of γ-AlON:Sm and γ-AlON:Yb.     

Preparation and characterization of MnOOH and β-MnO2 whiskers

MnOOH and β-MnO₂ whiskers are obtained for the first time in our work. MnOOH whiskers are chemically synthesized in the presence of cationic surfactant cetyltrimethylammonium bromide (CTAB). The product is obtained under extremely low surfactant concentrations under basic conditions, using MnSO₄·H₂O as the manganese source and ethylamine as the alkali source. After the subsequent heat treatment of MnOOH at 300 °C for 1 h, β-MnO₂ whiskers retaining the similar morphologies are obtained. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermogravimetry analysis (TGA) are used to characterize the products.     

Asymmetric synthesis and conformational analysis by NMR spectroscopy and MD of Aba- and α-MeAba-containing dermorphin analogues

Dermorphin analogues, containing a (S)‐ and (R)‐4‐amino‐1,2,4,5‐tetrahydro‐2‐benzazepin‐3‐one scaffold (Aba) and the α‐methylated analogues as conformationally constrained phenylalanines, were prepared. Asymmetric phase‐transfer catalysis was unable to provide the (S)‐α‐Me‐o‐cyanophenylalanine precursor for (S)‐α‐MeAba in acceptable enantiomeric purity. However, by using a Schöllkopf chiral auxiliary, this intermediate was obtained in 88 % ee. [(S)‐Aba 3‐Gly 4]dermorphin retained μ‐opioid affinity but displayed an increased δ‐affinity. The corresponding R epimer was considerably less potent. In contrast, the [(R)‐α‐MeAba 3‐Gly 4]dermorphin isomer was more potent than its S epimer. Tar‐MD simulations of both non‐methylated [Aba 3‐Gly 4]dermorphin analogues showed a degree of folding at the C‐terminal residues toward the N terminus of the peptide, without however, adopting a stabilized β‐turn conformation. The α‐methylated analogues, on the other hand, exhibited a type I/I′ β‐turn conformation over the α‐MeAba 3 and Gly 4 residues, which was stabilized by a hydrogen bond involving Tyr 5‐H_N and D ‐Ala 2‐CO.     

Batch Comparisons of Sr and Ba Retention and Capacities on AnaLig® Sr-01 and Eichrom Sr Resins

The isolation of strontium from aqueous media may be required for environmental monitoring or nuclear forensics sample analyses.^[1–4] The prevalent method is to use a strontium selective extraction chromatographic resin. Two such products are Eichrom Technologies Sr resin and IBC Advanced Technologies AnaLig® Sr-01 resin. Eichrom Technologies Sr resin utilizes a crown ether (4,4′(5′)-di-t-butylcyclohexano-18-crown-6) diluted in 1-octanol and coated onto Amberchrom^TM CG71 resin, and IBC Advanced Technologies AnaLig® Sr-01 resin features a proprietary extractant covalently tethered to a silica support. The use of each resin is reported in the literature; Eichrom Sr Resin specifications, including the resin’s weight distribution ratio and capacity factor for analytes, have been reported but no such data have been published for IBC Analig® Sr-01 resin. In this work, batch studies were completed to determine the capacity and weight distribution ratio of both AnaLig® Sr-01 and Eichrom Sr resins for strontium and barium. This work shows that both resins retained Sr from aqueous samples, but Eichrom Sr resin provided superior Sr/Ba separation compared with Analig® Sr-01 resin.     

Structure and Complexation Studies on 2,2′-Bipyridyl and Trivalent Lanthanides

Separation of trivalent lanthanides (Ln) and trivalent actinides (An) is important task in reprocessing high-level liquid waste. In this study, the relationship between structures of complexes of 2,2′-bipyridyl (Bpy) and Ln (Nd, Er) and coordination strengths were investigated by X-ray diffraction and UV titration. With the decrease in ionic radius from Nd to Er, the N(Bpy)-Ln distance and N(Bpy)-Ln-N(Bpy) angle decreased, the dihedral angle of the Bpy pyridines increased, and the stability constant increased. This information about structure and coordination strength is important for designing better ligands for separating Ln and An ions.     

What do titano- and zirconocenes do with diynes and polyynes?

A thorough investigation of the reactions of diynes, R(C&tbd1;C)(2)R, and polyynes, R(C&tbd1;C)(n)()R, with titanocene and zirconocene was performed using the metallocene sources Cp(2)M(L)(eta(2)-Me(3)SiC&tbd1;CSiMe(3)) (M = Ti, L = -; M = Zr, L = THF, pyridine). The conversions show an array of different products generated in complexation, coupling, and cleavage reactions. These results include remarkable structures (e.g., five-membered metallacyclocumulenes) and reactions (e.g., C-C single-bond cleavage). In addition, the first C-C single-bond metathesis in homogeneous solution was discovered. The presented findings have been supported by theoretical studies.