Materials Science Forum Vol. 996

Abstract: Patients suffering from cardiovascular disease lack suitable stent. In this study, a new polymeric composite material was prepared by incorporating various concentrations of gamma-glycidoxypropyltrimethoxysilane (GPTMS) into silk fibroin (SF), aiming at achieving a novel composite film with superior mechanical and biological properties, in order to match the requirement of cardiovascular tissue engineering stents. Fourier transform infrared spectroscopy (FTIR) analysis showed that GPTM could promote SF to transform from the original alpha helix and random coil/extension chain conformation to the beta-folded conformation. Tensile experiment indicated tensile strength and breaking elongation of SF/GPTMS hybrid film reach the maximum with 20% GPTMS content. Within a certain range, the water drop contact angle of SF/GPTMS hybrid film is positively correlated with the content of GPTMS. Endothelial cells (ECs) are best grown on hybrid SF/GPTMS hybrid film with 20% GPTMS content.

Abstract: As the most common medical apparatuses, the scalpels are extensively used for tissue cutting. During the tissue cutting process, blood adhesion to the surface of the ordinary scalpel is unavoidable and seriously affects the usability of the scalpel, which may cause medical accidents. Therefore, developing an anti-blood scalpel is of great importance. Herein, we prepare a scalpel with outstanding anti-blood property through coating method. The cleaned ordinary scalpel is immersed in the mixed solution containing nanocomposite ceramic coatings and silicone oil. After drying, the anti-blood scalpel is obtained. It can be observed from the scanning electron microscope (SEM) images that the surface of the anti-blood scalpel possesses microstructures. Compared with the ordinary scalpel, our anti-blood scalpel demonstrates outstanding blood repellence. Blood droplets can easily slide on the anti-blood scalpel surface with ~5° sliding angle. Compared with the existing scalpels with anti-blood property, our scalpel has the ceramic slippery surface rather than the slippery liquid-infused porous surfaces (SLIPSs). The stability of the ceramic slippery surface is much better than the SLIPSs because the SLIPSs are vulnerable under high temperatures and the decomposition products possess poor biocompatibility, which are harmful to human health. Therefore, the anti-blood scalpel has great application prospects in medical treatment.

Abstract: Silver inorganic antibacterial agents have been widely used inbiotechnology, bioengineering science, electronics, optics and water treatment because of their strong bactericidal ability, high safety and durable antibacterial properties. In this paper, the preparation methods of silver nanoparticles are reviewed, including physical method, chemical method and biological method, in order to provide a reference for the further development and utilization of silver nano-antibacterial materials.

Abstract: A novel end-functionalized glycopolymer poly (3-O-methacryloyl-D-glucofuranose) -b-poly (2-Diethylaminoethyl Methacrylate) (PMAGlc-b-PDEA-ZnTAPc) with zinc (II) teraamaninophthalocyanine was synthesized. First, a pH-responsive copolymer PMAIpG-b-PDEA was synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Then PMAIpG-b-PDEA reacted with ZnTAPc and deprotected to form a water-soluble and pH-responsive photosensitizer. The structure of the PMAGlc-b-PDEA-ZnTAPc was characterized by ¹H NMR and GPC. The photophysical properties were evaluated by UV-Vis and fluorescence spectra. The PMAGlc-b-PDEA-ZnTAPc can generate singlet oxygen species with good singlet oxygen quantum yields (Φ_△=0.38), which is believed to be the major cytotoxic reactive oxygen species (ROS) for photodynamic therapy. The ZnPc functionalized glycopolymer will be used as a potential photosensitizer in the fields of photodynamic therapy.

Abstract: A cementitious system embedded in microcapsules can achieve self-healing, and the fracture and triggering behavior of microcapsules is with great importance. In this study, the crack behavior of the concrete-microcapsule system was simulated by a three-dimensional lattice model. Based on the results of the fracture energy test on concrete beams and the nanoindentation test on microcapsules, the local mechanical properties of the lattice elements were determined. The aim of this paper is to set up a three-dimensional lattice model to study the trigger mechanism of the microcapsule-interface-concrete zone.

Abstract: In order to reduce the environmental burden and the energy consumption of PVA fiber reinforced high toughness cementitious composites, special focus is placed on the influence of fly ash type and content and curing type on the flexural performance of high toughness cementitious composites through four-point bending tests. The high toughness cementitious composites without fly ash have been used in the program for comparison purpose. The tests results show that, compared with the basic high toughness cementitious composites, the flexural strength decreases and the deflection increases with the s/b increasing when the fly ash is added. The increase in fly ash content results in an improvement of strain hardening property and increases in both flexural strength and deflection, which show that fly ash is benefit to the pseudo strain hardening performance. However the effects of fly ash type and curing type are not obvious on the load but obvious on the deflection. The deflection of high toughness cementitious composites with type I fly ash or water curing is higher than that of type II or standard curing. It is demonstrated that all the high toughness cementitious composites studied in this paper exhibit strain-hardening and multiple cracking through adding fly ash.

Abstract: In this study, Na₂CO₃ solution as a self-healing agent was impregnated in LWA for autonomic self-healing on cracked cementitious material. The results showed that under the joint action of expansive agent, crystalline additive, phosphate and carbonate, the crack area showed a high self-healing efficiency (close to 70%) after curing in the still water 28d. SEM-EDS test results showed that in addition to ettringite and C-S-H/C-A-S-H, there was also a large amount of CaCO₃ crystal in the depths of the crack.

Abstract: Since the rapid development of the construction industry, the production of construction waste has also multiplied, and the construction waste has caused tremendous pressure on the environment. Therefore, the main research of this subject is that the waste concrete is formed into a recycled material after a certain treatment--concrete powder. And the cement in the dry-mixed mortar is replaced by 0-30% concrete powder. The compressive strength of recycled concrete powder under different dosages was tested by experimental method. The compressive strength is then applied to the artificial neural network to establish a predictive model. Taking time as a variable, the feasibility and the best dosage of the 28-day compressive strength method for the 3d compressive strength during the test are discussed. In order to reduce the test cycle, improve work efficiency, and ultimately achieve the purpose of improving construction waste utilization.

Abstract: Taking fluidity and compressive strength of mortar as index, steel slag slag composite admixture replaces cement by 50%. The influence of the fineness and content of steel slag powder on the properties of composite admixture was studied by uniform experimental design. The fitting regression equation between the parameters of steel slag fineness and dosage and the performance indexes is established, and the contour map is drawn. The results show that the predicted value is in good agreement with the measured value, and the correlation coefficient is more than 0.99. Through regression analysis and contour map analysis, it is shown that increasing the fineness of slag powder and reducing the content of slag are beneficial to improving the cementitious activity of slag composite.

Abstract: Cu-14Fe-0.05C alloy was prepared by using the vacuum melting process and then multipass drawing deformation was performed. After that, the alloy in the as-drawn state was annealed. Based on this, the influence of annealing temperature on microstructure, mechanical performance and electrical conductivity of the alloy was studied. The results showed that the speed of recovery and recrystallization of the as-drawn Cu-14Fe-0.05C alloy accelerates and iron-rich fibers gradually become slender, bend and fracture, with the increase of annealing temperature. The tensile strength of the alloy constantly decreases, while elongation continuously rises and resistivity gradually reduces. With the extension of annealing time, tensile strength and resistivity of the Cu-14Fe-0.05C alloy gradually decreases, while elongation gradually increases.