Abnormal IR Spectra of CO Adsorbed on the Surface of Glass Carbon Electrode Modified with Polypyrrole Film with Platinum Microparticles

Abnormal IR spectra of CO adsorbed at the surface of glass carbon electrode modified with polypyrrole film with Pt microparticles are reported.

Study of the Diffusion Behavior of Seawater Absorption in Multi-Walled Carbon Nanotubes/Halloysite Nanotubes Hybrid Nanofillers Modified Epoxy-Based Glass/Carbon Fiber Composites

In the maritime industry, cost-effective and lightweight Fiber Reinforced Polymer (FRP) composites offer excellent mechanical properties, design flexibility, and corrosion resistance. However, their reliability in harsh seawater conditions is a concern. Researchers address this by exploring three approaches: coating fiber surfaces, hybridizing fibers and matrices with or without nanofillers, and interply rearrangement. This study focuses on evaluating the synergistic effects of interply rearrangement of glass/carbon fibers and hybrid nanofillers, specifically Multi-walled carbon nanotubes (MWCNT) and Halloysite nanotubes (HNT). The aim is to enhance impact properties by minimizing moisture absorption. Hybrid nanocomposites with equal-weight proportions of two nanofillers: 0 wt.%, 1 wt.%, and 2 wt.% were exposed to seawater for 90 days. Experimental data was subjected to modelling through the application of Predictive Fick’s Law. The study found that the hybrid composite containing 2 wt.% hybrid nanofillers exhibited a 22.10% increase in impact performance compared to non-modified counterparts. After 90 days of seawater aging, the material exhibited enhanced resistance to moisture absorption (15.74%) and minimal reduction in impact strength (8.52%) compared to its dry strength, with lower diffusion coefficients.

Electrochemical Study and Application on Shikonin at Poly（diallyldimethylammonium chloride） Functionalized Graphene Sheets Modified Glass Carbon Electrode

The electrochemical behaviors of shikonin at a poly（diallyldimethylammonium chloride） functionalized graphene sheets modified glass carbon electrode（PDDA-GS/GCE） have been investigated. Shikonin could exhibit a pair of well-defined redox peaks at the PDDA-GS/GCE located at 0.681 V（Epa） and 0.662 V（Epc）[vs. saturated calo- mel electrode（SCE）] in 0.1 mol/L phosphate buffer solution（pH=2.0） with a peak-to-peak separation of about 20 mV, revealing a fast electron-transfer process. Moreover, the current response was remarkably increased at PDDA- GS/GCE compared with that at the bare GCE. The electrochemical behaviors of shikonin at the modified electrode were investigated. And the results indicate that the reaction involves the transfer of two electrons, accompanied by two protons and the electrochemical process is a diffusional-controlled electrode process. The electrochemical para- meters of shikonin at the modified electrode, the electron-transfer coefficient（a）, the electron-transfer number（n） and the electrode reaction rate constant（ks） were calculated to be as 0.53, 2.18 and 3.6 s^-1, respectively. Under the optimal conditions, the peak current of differential pulse voltammetry（DPV） increased linearly with the shikonin concentra- tion in a range from 9A72×10^-8 mol/L to 3,789×10^-6 mol/L with a detection limit of 3,157× 10^-8 mol/L. The linear regression equation was Ip=O.7366c＋0.7855（R=0.9978; lp： 10-7 A, c： 10-8 mol/L）. In addition, the modified glass carbon electrode also exhibited good stability, selectivity and acceptable reproducibility that could be used for the sensitive, simple and rapid determination of shikonin in real samples. Therefore, the present work offers a new way to broaden the analytical application of graphene in pharmaceutical analysis.

Kinetics of Glass Transition and Crystallization in Carbon Nanotube Reinforced Mg-Cu-Gd Bulk Metallic Glass

Mg65Cu25Gd10 bulk metallic glass and its carbon nanotube reinforced composite were prepared. Differential scanning calorimeter （DSC） was used to investigate the kinetics of glass transition and crystallization processes. The influence of CNTs addition to the glass matrix on the glass transition and crystallization kinetics was studied. It is shown that the kinetic effect on glass transition and crystallization are preserved for both the monothetic glass and its glass composite. Adding CNTs in to the glass matrix reduces the influence of the heating rate on the crystallization process. In addition, the CNTs increase the energetic barrier for the glass transition. This results in the decrease of GFA. The mechanism of the GFA decrease was also discussed.

Effect of Ultrasonication on the Properties of Multi-walled Carbon Nanotubes/Hollow Glass Microspheres/Epoxy Syntactic Foam

Multi-walled carbon nanotubes（MWCNTs） reinforced hollow glass microspheres（HGMs）/epoxy syntactic foam was fabricated. The effects of ultrasonication on the density, compression strength, and water absorption properties were studied. Better dispersed MWCNTs can be obtained after ultrasonication treatment, but an increasing viscosity will lead to a larger amount of voids during syntactic foam preparation especially when the content of HGMs is more than 70 vol%. The existing voids will decrease the density of epoxy syntactic foam. However, the ultrasonication does not change the compression strength much. Ultrasonication treatment will decrease the water absorption content due to the better dispersion and hydrophobic properties of MWCNTs. But a significant increase of water absorption content occurs when HGMs is more than 70 vol%, which is attributed to the higher viscosity and larger amount of voids.

High-cycle Fatigue Life Extension of Glass Fiber/Polymer Composites with Carbon Nanotubes

The present work shows that the addition of small volume fractions of multi-walled carbon nanotubes （CNTs） to the matrix results in a significant increase in the high-cycle fatigue life. It is proposed that carbon nanotubes tend to inhibit the formation of large cracks by nucleating nano-scale damage zones. In addition, the contribution to energy absorption from the fracture of nanotubes bridging across nano-scale cracks and from nanotube pull-out from the matrix are mechanisms that can improve the fatigue life. An energy-based model was proposed to estimate the additional strain energy absorbed in fatigue. The distributed nanotubes in the matrix appear to both distribute damage as well as inhibit damage propagation resulting in an overall improvement in the fatigue strength of glass fiber composites.

MECHANICAL PROPERTIES OF CARBON/GLASS FIBER REINFORCED POLY(METHYL METHACRYLATE)COMPOSITES

Artificial bone, carbon/glass fiber reinforced PM-MA composites have been prepared by hot press moulding of pre-preg -which monofilments of CF and GF impregnated by MMA prepolymer. When the PMMA volume fraction in com-posites is 50% > theoretical and experimental results show that strength and modules of these hybrid composites are in accord with 'rule of mixture'. The tensile and flexure strength are the lowest when the raletive volume fraction of carbon fiber in rein-forcements is 50%,SEM examinations further explained re-sults.

Influence of Angle Ply Orientation on Tensile Properties of Carbon/Glass Hybrid Composite

Hybrid composites are considered materials of great potential for engineering applications. One advantage of hybrid composite materials for the designer is that the properties of a composite can be controlled to a considerable extent by the choice of fibers and matrix and by adjusting the orientation of the fiber. The scope for this tailoring of the properties of the material is much greater, however, when different kinds of fiber orientations are incorporated in the same resin matrix. For the study of potential of these materials, in this work specimens were prepared with different angle ply ori entation of carbon/glass hybrid with epoxy resin as an adhesive. Three orientations viz 0°/90°, 45°/45° and 30°/60° were considered for studies. Mechanical properties such as tensile strength, tensile modulus, & peak load of the hybrid com posites were determined as per ASTM standards. Vacuum bagging technique was adopted for the fabrication of hybrid specimens. It was observed that angle ply orientation at 0°/90° showed significant increase in tensile properties as compared to other orientation. Scanning electron micrographs of fractured surfaces were used for a qualitative evaluation of interfacial properties of woven carbon-glass hybrid composites. These results indicated that carbon-glass hybrid composites offered the merits of synthetic fibers.

Influence of Glass Dust on Properties of Alumina-carbon Refractories

In order to improve the properties of alumina-carbon refractories,specimens were prepared using white fused corundum,zirconia-mullite and flake graphite as the raw materials,phenolic resin as the binder,adding different mass fractions(1.5%,2.0%,and 2.5%,respectively)of glass dust,cold isostatic pressing by 120 MPa,drying and firing at 900℃for 3 h.Effects of the glass dust addition on the apparent porosity,bulk density,cold modulus of rupture,hot modulus of rupture and thermal shock resistance were studied.The results show that the cold modulus of rupture of the specimens is improved significantly as the results of glass dust accelerating sintering.However,the hot modulus of rupture decreases.As the glass phase buffers the strain produced by thermal shock,the thermal shock resistance of alumina-carbon specimens is improved,especially for low carbon alumina-carbon materials.

Adsorption of Cu and Ni Ions from Aqueous Solutions by Commercial Activated Carbon and the Reutilization in Glass Coloration

Toxic Cu(Ⅱ) and Ni(Ⅱ) ions in aqueous solutions were adsorbed by microporous activated carbon(AC). The adsorption isotherm and kinetics correlation coefficients indicate that the adsorption of Cu(Ⅱ) and Ni(Ⅱ) ions on the AC fits the pseudo second-order rate model and Langmuir adsorption model. The used AC adsorbents containing the adsorbed Cu and Ni ions were used as colorant in glass preparation. The coloration effect of Cu ions was influenced by the carbon absorbent included in the glass batch due to the reduction phenomenon, while the coloration of Ni ions was not affected.

Thermo-Stamping Process of Glass and Carbon-Fibre Reinforced Polymer Composites

In this work, manufacturing tools for thermoplastic (TP) composites have been developed. The chosen process involves the stacking alternately of oriented dry fabrics and TP films and does not use semi-products in order to reduce material costs. This study was specifically directed towards optimizing the impregnation of continuous glass and carbon fibres reinforcing two TP amorphous matrices, the polyphenylsulfone (PPSU) and polyetherimide (PEI), to obtain semi-finished products employed for aeronautical structures. The impregnation quality of inter and intra-yarns is analyzed and validated by optical and scanning micrographic observations conducted with an optical and a Scanning Electron Microscopies (SEM), respectively. The study showed that besides the process parameters and porosity distribution in the core of warp yarns, the impregnation quality depends on the surface properties of constituents. Desizing treatment has been carried out to improve the wettability of fibres by the TP matrices.

Molecular Dynamic Simulation Study on Glass Transition Temperature of DGEBA-THPA/SWCNTs Composites

Molecular dynamic (MD) simulations were carried out to predict the thermo-mechanical properties of the cured epoxy network composed of diglycidyl ether bisphenol A (DGEBA) epoxy resin and tetrahydrophthalic anhydride (THPA) curing agent and their single-walled carbon nanotubes (SWCNT) reinforced the epoxy matrix composites. Different characters such as the density of the materials and mean square displacements (MSDs) were calculated to estimate the glass transition temperatures (Tgs) of of the materials. 365 K and 423 K of the Tgs were obtained respectively, whereas the latter is much higher than the former. The simulation results indicated that the incorporation of SWCNTs in the epoxy matrix can significantly improve the Tg of the cured epoxy. The approach presented in this study is ready to be applied more widely to a large group of candidate polymers and nanofillers.

Chronology of Bioactive Glass Development and Clinical Applications

The key research and development steps for bioactive glass (45S5 Bioglass) are documented from the date of discovery in 1969 through FDA approvals of the first dental, ENT, maxillo-facial and orthopedic clinical products. Understanding the mechanisms and quantifying the rapid surface reactions to form a bone-bonding hydroxyl-carbonate apatite (HCA) layer on the bioactive glass in contact with living bone was a vital part of the early development of this class of biomaterials. A key later discovery was enhanced osteogenesis and in situ bone regeneration by controlled release of ionic dissolution products from the bioactive glass particulates that leads to up-regulation and activation of seven families of genes, a process called osteostimulation.

Improvement in Mechanical and Thermo-Mechanical Properties of Epoxy Composite Using Two Different Functionalized Multi-Walled Carbon Nanotubes

In this study, two types of functionalized multi-walled carbon nanotubes were dispersed in an epoxy resin system (SC-15) at room and elevated temperatures using a combination of sonication and high shear mixing methods to determine optimal mechanical and thermal properties. At first, 0.1 wt% - 0.3 wt% of amino-functionalized multi-walled carbon nanotubes (MWCNT-NH2) and carboxyl-functionalized multi-walled carbon nanotubes (MWCNT-COOH) were dispersed in part-A of SC-15 resin using a combination method. The mixture was then added to part-B of epoxy resin and cured using two different cycles (cycle A: at room temperature for 24 hours and post-cure at 93.33?C for 4 hours, cycle B: at 65.56?C for 5 hours). In addition, control samples (without MWCNTs) were also fabricated for baseline consideration under similar conditions. In all cases, epoxy with MWCNTs showed improved performance. Improvements in properties in MWCNT/epoxy samples prepared using cycle A were comparatively lower than samples prepared with cycle B. Flexural and thermo-mechanical results demonstrated maximum improvement in 0.2 wt% MWCNT-COOH modified epoxy samples prepared using cycle B. Improvements in performance for samples cured at elevated temperatures were attributed to better dispersion of MWCNTs due to reduced viscosity. On the other hand, increased number of functional groups present in MWCNT-COOH contributed to higher crosslinking resulting in the highest observed properties.

我国建筑玻璃工业碳排放量预测

建筑玻璃工业属于能源和碳排放密集型产业,行业本身减排难度大同时肩负建筑领域碳中和重任,建筑玻璃需求仍将持续增长,进一步加大减排难度。通过分析2010—2022年建筑面积和建筑玻璃产量数据,对建筑玻璃面积-建筑面积进行线性拟合,结合对未来建筑面积的情景分析,预测2023—2040年建筑玻璃需求量和碳排放量,并量化分析减薄等主要达峰路径。预测结果分析可得:加速减薄玻璃厚度,在保障建筑对玻璃面积规模需求的同时,可实现建筑玻璃工业碳达峰。

国外平板玻璃行业碳中和技术路径跟踪研究

近年来,气候变化已经成为当今人类发展共同面临的严峻挑战,开展碳减排行动已成为全球共识。玻璃工业同样面临碳排放的现实问题。围绕国外平板玻璃行业碳中和技术路径的研究及应用现状,开展玻璃行业碳排放现状与碳中和技术路线的分析与研究,掌握碳排放来源,提出实施碳中和的有效路径,有助于推动玻璃行业节能降碳。

基于Giannakoopulou模型的MWCNT/GF/EP复合材料微波吸收性能研究

探究了加入不同质量分数多壁碳纳米管的多壁碳纳米管/玻璃纤维/环氧树脂复合材料在X波段的电磁波吸收性能,基于Giannakoopulou模型引入透波层,研究了吸波层和透波层两者的比例和分布状态对吸波材料整体的吸波性能影响。结果表明,加入多壁碳纳米管质量分数为2%的多壁碳纳米管/玻璃纤维/环氧树脂复合材料在厚度为3.0 mm时,最大反射损耗为-44.5 dB,有效吸收带宽为3.3 GHz(8.2~11.5 GHz);通过合理设计吸波层和透波层两者的比例和分布状态,得到具有不同有效吸收带宽和吸收损耗峰值的吸波材料,反射损耗峰值最高达到-62.1 dB,有效吸收带宽为3.1 GHz。

高性能胶浸渍碳纤维束的拉伸性能研究

为进一步加强碳纤维编织网增强混凝土(Carbon Textile Reinforced Concrete, CTRC)的力学性能,需对纤维束进行浸胶处理,常用的胶粘剂中环氧树脂不耐高温、钠水玻璃不耐水、碱激发胶凝材料不适合浸渍碳纤维,为了研制耐水、耐碱、耐高温、适合浸渍碳纤维的高性能胶,以界面剂与钠水玻璃的质量比作为变量,测试浸胶碳纤维束在常温、水以及碱性溶液环境下(1、2、4 d)的拉伸强度。将浸胶后的碳纤维束置于地聚物净浆中以及高温环境中,研究实际工作环境对浸胶碳纤维束拉伸强度的影响,最后借助扫描电子显微镜和能谱仪观察其微观结构特征和表面的元素变化。研究结果表明:相比未浸胶碳纤维束,室温下浸渍高性能胶后的碳纤维束拉伸强度显著提升(约72.4%)。高性能胶中掺入的界面剂含量越大,胶体的耐水、耐碱性越强,但胶体的硬度越低。如果界面剂掺量不小于钠水玻璃质量的0.5倍,胶体具有良好的耐水和耐碱性,可在地聚物净浆中保持其黏结性能。如果钠水玻璃和界面剂质量相等,浸胶碳纤维束在200℃温度下拉伸强度只降低7%,表明其耐高温性能好。此外,扫描电镜和能谱仪的结果表明高性能胶的成膜性好,表面并未观察到孔洞等缺陷,且胶体在浸水后未软化,表面Si元素也没有明显减少,说明界面剂的掺入可以很好地保护水玻璃凝胶,有效改善水玻璃胶体耐水性差的特点。高性能胶中界面剂最佳掺量为钠水玻璃质量的0.5~1倍。研究结果为进一步研制耐高温CTRC材料提供参考。

碱激发低碳混凝土的力学性能与提升机理研究

针对水泥在生产利用过程中产生的碳排放问题及固废材料在大掺量条件下替代水泥制备混凝土导致其力学性能下降的问题,利用4%Na_(2)SiO_(3)对玻璃粉(GP)进行碱激发处理,随后替代50%的水泥制备低碳混凝土。结果表明,低碳混凝土的力学性能远低于普通混凝土,而Na_(2)SiO_(3)掺入使低碳混凝土力学性能得到一定程度的提升,在各龄期内抗压强度分别提升了22.6%、27.5%、19.8%和17.2%;劈裂抗拉强度增长了21.3%、20.6%、18.2%和16.3%。Na_(2)SiO_(3)使玻璃粉(GP)中丰富的SiO_(2)在OH-的作用下出现较为明显的解构现象,使其在低碳混凝土内部与Ca、Na、K等元素结合生成了更多的C-S-H凝胶、C-A-S-H凝胶、N-A-S-H凝胶,同时还产生了强度更高的钾A型沸石晶体,使得低碳混凝土的大孔隙含量降低,孔隙结构得到优化,进而导致低碳混凝土力学性能得到大幅提升。研究为降低碳排放及固废在混凝土中大掺量的使用提供了新思路、新见解。