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Piezoelectric damping composites with excellent damping properties were prepared from carbon black (CB), lead magnesium niobate (PMN), epoxy resin, and polyether amine D-400. The tanδ{\rm{\tan }}\delta area (TA) analysis method is used to evaluate the leading factors of damping enhancement. This method clearly shows the influence of the maximum loss factor (tanδ{\rm{\tan }}\delta max) and effective damping temperature range on damping performance, and the damping enhancement factors are quantitatively analyzed by TA values. When CB content is less than 8 wt%, viscoelastic damping and frictional energy dissipation are the main factors affecting polymer properties. When CB content reaches 8 wt%, the conductive network gradually forms, and the electric energy generated by PMN through the piezoelectric effect is dissipated by the conductive network, and the piezoelectric effect of PMN becomes the dominant factor. In this case, the maximum tanδ\tan \delta max and TA values of the composite are 1.93 and 27.58, respectively. The damping contribution of PMN and CB reaches 40.21% and 34.41%, respectively.

In this article, nano-ZrSi2-modified phenolic (Ph) resin and nano-ZrSi2-modified quartz–phenolic (Q–Ph) composites are, respectively, prepared by resin casting and compression molding. The effect of nano-ZrSi2 on the thermal stability of Ph resin and the role of nano-ZrSi2 on the thermal reusability of Q–Ph composites are investigated by multiple thermal gravimetric analyses and mechanical tests. The strengthening mechanism of nano-ZrSi2 modification is investigated by the evolution of microstructure. The results show that the addition of nano-ZrSi2 enhances the thermal stability of Ph resin under repeated heating at 1,200°C in air. The enhancement in thermal stability of resin exhibits a positive effect on improving the thermal reusability of composites. Within the range of 20 repeated heating times, the flexural strength of nano-ZrSi2-modified composites is above 16.01 MPa, which is 163.8% higher than that of unmodified composites. The strengthening mechanism of nano-ZrSi2 is mainly in the inhibition of thermal oxidation and the reduction of microstructural defects during the repeated thermal environment.

The large-scale application of phenolic aerogel is limited by its complex and lengthy production process as well as its expensive cost. Herein a simultaneous drying-curing method for phenolic aerogels was designed based on the sol–gel process, and a series of phenolic aerogels with different hexamethylenetetramine (HMTA) contents were prepared. The material parameters such as microstructure, pore structure, mechanical properties, shrinkage, and density of the aerogel were characterized. The results show that compared with the conventional full-sealing method, the simultaneous drying-curing method shortens the preparation time of aerogels by nearly half and improves the safety of the preparation process. The prepared phenolic aerogels still maintain the nanoporous microscopic morphology. When the HMTA content is 1/6 of the phenolic mass, the linear shrinkage rates of the aerogels prepared by this method and the conventional full-sealing method are 9.8 and 9.4%, respectively. The densities are 0.25 and 0.22 g·cm−3, and the BET specific surface areas are 54.42 and 54.31 m2·g−1, and the compressive yield strengths are 1.76 and 1.16 MPa. At the same time, the thermal conductivity of the phenolic aerogels prepared by the simultaneous drying-curing method is less than 0.06 W·(m·K)–1 at room temperature. These results indicate that the properties of the aerogels prepared by the simultaneous drying-curing method are close to those prepared by the conventional method, which proves that this method has guiding significance for the large-scale, low-cost, and rapid production of nanoporous phenolic aerogels.

The percolation thresholds of poly ether ether ketone/graphene (PEEK/Gr) composites in most studies are high due to the random distribution of Gr in the matrix. Here, aminated poly-ether-ether-ketone/graphene network (PEEK-NH2/GN) nanocomposites were prepared by electrostatic adsorption of PEEK-NH2 with positive charges and graphene oxide with negative charges, followed by in -situ reduction and hot-pressing. The GN structure of composites was well presented in the images of scanning electron microscope. The PEEK-NH2/GN nanocomposites exhibited excellent electrical conductivity with a maximum conductivity of 0.0634 S·cm−1 and a percolation threshold as low as 0.25 vol%. In addition, the maximum tensile strength of nanocomposites was reached at 93 MPa when the Gr content was 0.5 wt%. We believe that this approach is a new avenue for the production of low filler high conductive polymer composites with potential commercial prospects in various fields.

Epoxy sheet molding compound (ESMC) composites have excellent mechanical properties, dimensional stability and electrical insulation, and are widely used in the automotive industry. In our previous work silane coupling agent modified, hollow glass microspheres (SiHGM) and montmorillonite (MMT) were incorporated to enhance the mechanical properties of the ESMC composites. It was found that the ESMC composites containing MMT (EP/SiHGM/MMT-1) exhibited excellent mechanical strength. However, the flammability of the epoxy resin (EP) limits the use of ESMC composites for applications that require good flame retardancy. In this paper we describe our research in which MMT was used to increase the flame retardancy of ESMC composites. The results showed that the addition of MMT made the ESMC composites have excellent flame retardancy. The limiting oxygen index (LOI) of the ESMC composites containing 1 phr MMT (EP/SiHGM/MMT-1) was 26.8%, which was 8.94% higher than that of the ESMC composites without MMT (EP/SiHGM/MMT-0). In addition, the peak heat release rate (PHRR), average heat release rate (AHRR) and total heat release (THR) of the EP/SiHGM/MMT-1 were 322.8 kW/m2, 95.3 kW/m2 and 38.6 MJ/m2, respectively, which were 22.6%, 8.2% and 8.0% lower than those of EP/SiHGM/MMT-0. The carbon monoxide production (COP) and carbon dioxide production (CO2P) of EP/SiHGM/MMT-1 were 0.0092 g/s and 0.2071 g/s, respectively, which were 34.3% and 22.8% lower than those of EP/SiHGM/MMT-0. The fire growth index (FGI) of EP/SiHGM/MMT-1 was 2.4, which was a decrease by 29.4% compared to EP/SiHGM/MMT-0. In addition, the flame retardant mechanisms were revealed. We suggest that MMT promoted dehydration and charring of the epoxy resin and helped construct an intact physical barrier, which had good blocking effects. The prepared composite has great application prospects for those occasions that require high flame retardancy. Thus, this work provides an innovative strategy for preparing low density epoxy composites with excellent flame retardancy and high mechanical properties. [ABSTRACT FROM AUTHOR]

Phenolic epoxy resin (F51) was first reacted with silane coupling agent (3-aminopropyl)triethoxysilane (KH550) to form a silanized phenolic epoxy resin (SPER); then the SPER was copolymerized with methylphenyl silicone resin (MPS) to synthesize phenolic epoxy modified silicone copolymer (PEMSC). The chemical structure of the PEMSC was characterized by FT-IR. The results of tensile strength and shear strength measurements indicated that the successful introduction of F51 significantly improved the mechanical and adhesive properties of the PEMSC; compared with the PEMSC with 10 phr of F51 added, the tensile strength and shear strength of the PEMSC with 40 phr increased by 8.5 and 3.5 times respectively. The TGA and DTGA analysis showed that the initial thermal decomposition temperature and the residual weight of PEMSC at 800 °C decreased compared to MPS, but the temperature corresponding to the maximum thermal decomposition rate in the second stage increased. Qualitative analysis was conducted on the decomposition products of PEMSC using gas chromatography coupled with mass spectrometry (GC-MS). The results showed that the relative content of aromatic hydrocarbons and their derivatives in the decomposition products of PEMSC was 64.11%, and the relative content of cyclic trimers and higher cyclomers was 20.41%. [ABSTRACT FROM AUTHOR]

Non-specific lower back pain (NLBP) is treated with a variety of therapies, including health education, exercise therapy, soft tissue release, psychological interventions, and shockwave therapy. However, some studies have shown that core stability training or fascial release therapy alone is not effective in the treatment of low back pain. The aim of this study was to investigate the effects of core stability training on patients’ inflammatory cytokine levels and lumbar muscle temperature when combined with fascial release for the treatment of non-specific low back pain. In this study, a total of 60 patients with non-specific low back pain who were treated in Mindong Hospital of Ningde City between December 2021 and January 2023 were selected and randomly and equally divided into a control group (30 cases) and an experimental group (30 cases). The control group received core stability training, while the experimental group added fascial release surgery to this. We compared and assessed the pain visual analog score (VAS), Oswestry dysfunction index (ODI), lumbar spine mobility (including anterior flexion, posterior extension, left flexion, and right flexion), as well as levels of inflammatory factors IL-6, TNF-a, and muscle tissue temperature in the two groups. This study has been successfully implemented and covered 60 patients throughout the trials. Upon comparison, the two groups did not show statistically significant differences in baseline data such as age, gender and duration of disease (p> 0.05). After four weeks of treatment, the test group showed statistically significant (p< 0.05) differences in VAS scores, ODI scores, and IL-6 and TNF-a levels that were significantly lower than those of the control group. It is worth mentioning that the muscle tissue temperature of the patients in the test group, as well as their performance in lumbar anterior flexion, posterior extension, left flexion, and right flexion mobility, were significantly better than those of the control group, and these differences also showed statistical significance (p< 0.05). The combination of core stability training and fascial release demonstrates significant clinical results in the treatment of nonspecific lower back pain. Through medical thermography and serum inflammatory factor testing, we were able to assess the treatment effect more objectively, providing a strong basis for future clinical practice. [ABSTRACT FROM AUTHOR]

Ceftazidime/avibactam (CAZ/AVI) is a combination of a well‐known third‐generation, broad‐spectrum cephalosporin with a new beta‐lactamase inhibitor that has been approved for the treatment of various infectious diseases (especially multidrug‐resistant Gram‐negative bacterial infections) by the Food and Drug Administration (FDA). The current study extensively assessed CAZ/AVI‐related adverse events (AEs) in the real world through data mining of the FDA Adverse Event Reporting System (FAERS) database to better understand toxicities. The signals of CAZ/AVI‐related AEs were quantified using disproportionality analyses, including the reporting odds ratio, the proportional reporting ratio, the Bayesian confidence propagation neural network, and the multi‐item gamma Poisson shrinker algorithms. Out of 10,114,815 records retrieved from the FAERS database, 628 cases were identified, where CAZ/AVI was implicated as the primary suspect drug. A total of 61 preferred terms with significant disproportionality that simultaneously met the criteria of all four algorithms were retained. Several unexpected safety signals may also occur, including melena, hypernatremia, depressed level of consciousness, brain edema, petechiae, delirium, and shock hemorrhagic. The median onset time for AEs associated with CAZ/AVI was 4 days, with most cases occurring within 3 days after CAZ/AVI initiation. [ABSTRACT FROM AUTHOR]