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Expanded graphite (EG) exhibits excellent thermal property, high specific surface area, and large aspect ratio, which show promise for fabricating polymer composites with high thermal conductivity. However, the wormlike structure of EG makes it difficult to be exfoliated and dispersed in polymer matrix. To meet this challenge, herein, a one-step melt mixing strategy based on the phase-transition-assisted in-situ exfoliation is developed to fabricate EG-low density polyethylene composites with high thermal conductivity. SEM images and WAXD analyses showed that the internal force generated by phase transition makes EG to be quickly exfoliated and dispersed in melts within 8 min. POM images and DSC results suggested that the exfoliated EG can introduce heterogeneous nucleation to LDPE macromolecules and improve the crystallinity of composites. Moreover, the EG-LDPE composites prepared by this strategy have a thermal conductivity of 0.715 W[m.sup.-1] K.sup.-1] with the loading of 5 wt. % EG. This value exceeds the composites prepared by regular melt mixing, achieving the enhancement efficiency of graphene nanoplatelets (GNP). This strategy has great potential in preparing polymer composites with high thermal conductivity. KEYWORDS expanded graphite, in-situ exfoliation, phase transition, thermal conductivity, 1 | INTRODUCTION With the trend of integration, miniaturization, and increasing power density of electronic devices, heat dissipation is becoming crucial. [1] It means that heat sinks need to be [...]

Objective: To analyze the function of the left heart in patients with different courses of gout, the independent influencing factors for left heart functional changes, and interactions between left atrial and left ventricular functions. Methods: Patients with gout (n = 171) were selected; 87 patients with a disease course <10 years were included in Group I, and 84 patients with a disease course ≥10 years were included in Group II. Ninety‐four healthy volunteers comprised the control group. Results: The intergroup differences in cardiac strain parameters were statistically significant (p <.05). Moreover, the differences gradually declined with disease progression. Multivariate logistic regression analysis showed that uric acid was an independent predictor of decreased left ventricular global longitudinal strain (LVGLS). Moreover, LVGLS had a positive effect on the left atrial systolic rate (LASr) and the left atrial systolic contraction time (LASct) but no interaction with the left atrial systolic contraction duration (LAScd). Conclusion: The course of the disease significantly affected the function of the left heart in gout patients, and uric acid was observed to be an independent predictor of decreased LVGLS in gout patients. [ABSTRACT FROM AUTHOR]

In this work, a novel melt mixing method and its corresponding mixing device are developed. The extensional/shear strength ratio of the device can be controlled by adjusting its eccentricity. The structure and working principle of the device are introduced in detail. Carbon fiber (CF)/polyamide 6 (PA6) composites are prepared via this novel mixing device. The influences of eccentricity and mixing time on the morphology, CF length, thermal, mechanical, and electrical properties of CF/PA6 composites are studied. Scanning electron microscopy results show that CFs uniformly disperse in the matrix and interfacial adhesion between CFs and PA6 is improved. It is observed that CF length and its distributions can be optimized by changing eccentricity. The maximum average fiber length is about 351 [micro]m. Differential scanning calorimetry results exhibit that the [X.sub.c] increases 6.5% when eccentricity is 2 mm. Mechanical test results show tensile strength and modulus increase first and then decrease with the increasing eccentricities or mixing time. Electrical property measurement shows an obvious increase when eccentricity is 2 mm due to good fiber dispersion and long fiber retention length. The experimental results indicate that the novel mixing method and its corresponding apparatus provide an environment-friendly and effective way to prepare polymer-based composites. KEYWORDS carbon fibers, dispersive mixing, distributive mixing, extensional/shear strength, melt mixing, PA6, 1 | INTRODUCTION Polyamide 6 (PA6) has been commonly used as an engineering plastic in a wide range of fields including electronics, automobile, and packing industries, due to its advantages [...]

Although it is more cost-effective, producing hydrogen through acidic seawater splitting systems is still difficult, especially when it comes to creating highly effective, highly resistant chlorine corrosion bifunctional catalysts for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, under the addition of phosphotungstic acid and the etching effect of oxalic acid, we develop bifunctional P/W dual-doped RuOx nanocrystals for acidic overall seawater splitting, showing overpotentials of 45 and 158 mV for the HER and OER at 10 mA cm−2, respectively, and accompanied by a strong corrosion resistance towards seawater. Accordingly, the two-electrode system requires only 1.47 V to reach a current density of 10 mA cm−2 and maintains a high stability over 50 h. The P/W dual doping modulates the electrical environment of Ru sites, and the addition of oxalic acid encourages the exposure of more active sites, both of which contribute to the enhancement of seawater electrolysis. Theoretical calculations further manifest that the energy barriers of the HER and OER can be lowered by the dual-doping. Moreover, we found a positive influence of Cl− on the catalytic activity of acidic seawater splitting. Our work offers a promising strategy to significantly increase the catalytic efficiency of Ru-based catalysts for the generation of green hydrogen from acidic seawater in a sustainable manner. [ABSTRACT FROM AUTHOR]

Fill degree is a key parameter impacting twin screw extruders' (TSEs) mixing performance and melting behavior. The conventional conveying model of partially filled fluid relies mainly on empirical methods. A nontwin screw geometry introduces a speed difference between the two intermeshing screws to change the conveying means, and this speed difference offers a challenge for establishing a new conveying model. A visualization prototype with a global transparent barrel was developed in this article with carboxymethylcellulose sodium solution used as working fluid. Fill length was measured under different outputs and screw rotation speeds in a nontwin screw channel versus a corresponding twin screw channel; thus, fill degree was obtained using the observed fill lengths and nontwin screw geometries. A new conveying model of partially filled fluid was proposed which isolated positive displacement flow as an independent factor, and visualization observations revealed that due to differences in screw flight width, the positive displacement flow in a nontwin screw channel is larger than that in a traditional twin-screw channel. Results showed that dimensionless positive displacement conveying increased linearly with fill degree for a non-TSE geometry while it was independent of fill degree for a TSE geometry., INTRODUCTION Corotating twin-screw extruders (TSEs) are widely used in materials processing as well as in food and pharmaceutical preparation due to their flexible combinations, excellent mixing properties, and self-cleaning functions. [...]

Low-density polyethylene (LDPE)/multiwalled carbon nanotubes (MWCNTs) nanocomposites with different foaming agent (OBSH) contents were innovatively prepared via In Situ Bubble Stretching (ISBS) and synergistic cyclic volume stretching. The cyclic convergent and divergent flow makes the MWCNTs repeatedly subjected to bubble stretching, which is conducive to the efficient dispersion of MWCNTs in the matrix. The thermal weight loss of neat OBSH and nanocomposite were characterized by thermal gravimetric analyzer (TGA), which indicated that the OBSH in the nanocomposite had been completely decomposed into gas during the plasticizing transport process. The results of morphology showed that the moderate content of OBSH had better dispersion effect on MWCNTs. At optimal OBSH content, the OBSH could generate enough gas and larger bubbles per unit time to provide greater expansion forces to do much for the dispersion of MWCNTs. The dynamic mechanical analysis (DMA) was further carried out and also proved that the content of OSBH was an important factor for the dispersion of MWCNTs. Moreover, the relationship between the OBSH content and conductivity was discussed in details. The improvement in conductive properties of nanocomposites associated with the use of the method can be attributed to a more homogeneous dispersion of MWCNTs., 1. INTRODUCTION Carbon nanotubes (CNTs), as good nanofillers with unique structure and good performance [1, 2]. are usually dispersed into various polymeric matrixes to prepare polymer/CNTs nanocomposites. The polymer/CNTs nanocomposites [...]