Novel multilayer structural epoxy nanocomposite coating for enhanced adhesion and protection properties of steel

To evaluate the potential of halloysite nanotubes (HNT) as nanofiller for polylactide (PLA), various nanocomposites have been successfully produced by melt-blending the polyester matrix with HNT (HNT(QM)). HNT were also surface treated by silanization reaction with 3-(Trimethoxysilyl) propyl methacrylate (TMSPM). The morphology, thermal, tensile and impact strength properties of the nanocomposites containing 3–12 % HNT were evaluated and compared to those of pristine (unfilled) PLA. The nanocomposites were characterized by higher rigidity (with Young’s modulus increasing with HNT loading), higher tensile strength (about 70 MPa at 6 % HNT(QM)), whereas the elongation at break and impact strength did not decrease. As demonstrated under dynamic solicitation (DMA), melt-blending PLA with HNT led to enhancement of storage modulus (E′) and offers the possibility to use PLA in applications requiring higher temperatures of utilization. However, with few exceptions, TGA and DSC measurements did not reveal important changes of thermal parameters. The surface silanization treatment proved to improve the quality of the nanofiller dispersion even at higher loading. As a result, good thermal stability associated to high tensile strength, and noticeable increases in impact properties were recorded. Furthermore, enhanced nucleating ability and crystallization kinetics of the PLA matrix were revealed as specific characteristics.

The grafting of 3‐(trimethoxysilyl)propyl methacrylate (TMSPM) onto chitosan by ceric ion initiation was studied under homogeneous conditions in 2% acetic acid solution. The grafted polymer was characterized by FT‐IR, 1H‐NMR, TGA and XRD and swelling studies. TGA results showed that the incorporation of TMSPM to the chitosan chains decreased the thermal stability of the grafted chitosan. Due to the grafting of TMSPM, the crystallinity of chitosan derivatives was found to be destroyed. The solubility of the grafted chitosan in water was improved. The effects of reaction conditions such as initiator concentration, monomer concentration, reaction temperature and reaction time were studied by determining the grafting parameters such as grafting and grafting efficiency. Under optimum conditions, the grafting parameters were achieved as 1440 and 97%, respectively.

The tensile properties and morphological studies of linear low density polyethylene (LLDPE)/poly (vinyl alcohol) (PVA)/kenaf (KNF) composites with and without 3-(trimethoxysilyl) propyl methacrylate (silane coupling agent) were investigated. The composites with different KNF loading (10, 20, 30, 40 phr) were prepared using a Thermo Haake Polydrive internal mixer at 150°C and 50 rpm for 10 min. The results indicated that composites with 3-(trimethoxysilyl) propyl methacrylate gives higher tensile strength and modulus but lower elongation at break than composites without. The presence of 3-(trimethoxysilyl) propyl methacrylate found to enhance the interfacial adhesion between LLDPE/PVA matrix and KNF fiber. Morphological studies on tensile fractured surfaces showed good adhesion between LLDPE/PVA matrix and KNF, and better dispersion of KNF for the composites with 3-(trimethoxysilyl) propyl methacrylate.

Graft copolymerization of silicone monomer—3-(trimethoxysilyl) propyl methacrylate (TMSPMA) grafted onto styrene–butadiene–styrene (SBS; SBS- g-TMSPMA) triblock copolymer was carried out by free radical polymerization, and the improvement of adhesive property of the grafted SBS for glass materials is the major purpose of this study. To gain the optimal reaction conditions and grafting effect, the effect of various factors, such as the monomer ratio and reaction time, on the grafting ratio and grafting efficiency (GE) of SBS- g-TMSPMA graft copolymers were investigated. In addition, various SBS- g-TMSPMA graft copolymers were coated on different substrates based on glass and their tensile strengths that were tested. The optimal graft condition for the SBS- g-TMSPMA was obtained when the molar ratio of TMSPMA to SBS was 1 and reaction time was 4 h. Their grafting ratio and GEreached to a maximum of 56.8% and 60.2%, respectively, and the tensile strength also reached maximum. In this article, we confirm that the higher the grafting ratio, the more the silicone-containing in the graft copolymer. Hence, the –Si–O–Si– bonding between SBS- g-TMSPMA and glass substrate was more intensive and tensile strength was stronger.

The incorporation of functionalized graphene oxide (GO) in mixed matrix membrane (MMM) is expected to greatly increase the permeability and selectivity for O2/N2 separation. In the present study, GO functionalized with 3- (Trimethoxysilyl) propyl methacrylate (TMOPMA) was used as inorganic filler and incorporated in to a PVC/pAMPS based MMM to increase the separation efficiency. Membranes of different compositions were synthesized and the best morphology was achieved with 0.5 g of PVC, 1.0 g of pAMPS and 0.015 g of filler. The synthesized membrane and inorganic filler were characterized using SEM, EDS, FTIR, Raman and XRD spectroscopy. Moreover, the gas permeation studies were performed to check the separation factor of synthesized membrane for O2/N2. The maximum permeability achieved for O2 and N2 was 4097 and 3373 barrers, respectively at 5 bar pressure. For the selectivity, a gradual increasing trend was observed with the increase in permeability. The maximum selectivity achieved was 1.215 at 5 bar pressure. The results revealed an increasing trend in selectivity with the increase in permeability of gases across the membrane with the increase in feed gas pressure.

Particulate reinforced Aluminium based metal matrix composites are widely used in aerospace, defense, marine and space applications because their excellent properties such as high strength, high stiffness, high corrosion resistance, high fatigue resistance, high wear resistance etc., In the present work Aluminum Alloy Al6061-Zirconium dioxide composites were developed by stir casting technique by varying the percentage of Zirconium dioxide in steps of 3% up to 12%.The samples were prepared as per ASTM standards for microstructure study, tensile strength and hardness properties. The microstructure studies carried using optical microscope revealed the presence of Zirconium dioxide particulates in the Aluminium matrix. Also it revealed the uniform distribution of Zirconium dioxide in the Aluminium matrix and no voids and porosity were present in the matrix. The tensile strength and hardness properties were more than the base metal aluminium alloy. The tensile strength and hardness properties were increased with the increase in percentage of Zirconium dioxide up to 9% and decreased there afterwards. The optimum value for hardness and tensile strength of the composite was obtained at 9% of Zirconium dioxide.

Although ordinary Portland cement (OPC) is one of the most widely used construction materials in the world, its relatively weak tensile strength and proneness to cracks limit wider structural applications. Graphene oxide (GO) offers an interesting prospect of two-dimensional nanosheets in reinforcing OPC. Investigation of GO-reinforced cement composites is at a relatively early stage and very limited research into the effectiveness of GO in enhancing the tensile or flexural strengths of OPC is available. Thus there is a significant need for further studies in this area to understand the reinforcing behaviour of GO in cement matrix, including the dispersion of GO and the effect of GO on OPC paste in terms of mechanical properties, workability and microstructure. This study develops a fabrication protocol for the production of GO-paste and subsequently characterises the mechanical properties of the composite. Specifically, the objectives of this study are (1) to understand the procedure of preparing GO nanomaterial, (2) to study the dispersion behaviour of GO and (3) to investigate the role of GO in reinforcing cement matrix via mechanical properties and microstructural observations. As an emerging field of study, the procedure of incorporating GO nanomaterial into cement composites is yet to be established. During the production of GO, a two-step oxidation is applied to attach oxygen functional groups into the GO nanosheets. To ensure that GO is well dispersed in water as single-layered nanosheets, mild ultrasonication is supplied. The size distribution and dispersion quality of the GO produced is studied using zeta potential. This step is necessary to determine the optimal ultrasonication input, which is established as 15 J/mL. To develop high-performance GO-reinforced OPC paste, the dispersion of GO in water, alkali and aqueous solutions is studied. UV-vis confirms that only a mild sonication input is required for GO to be well dispersed in water. However, GO undergoes agglomeration when exposed to very alkaline solutions exceeding pH 13, highly concentrated ionic solutions, or in the presence of calcium ions. Therefore, the use of surfactants in the form of cement admixtures is crucial to protect GO against agglomeration. The incorporation of GO (of 0.02 wt.% of cement) substantially enhances the mechanical properties of plain cement. For example, the tensile strength is improved by 68.3% and flexural strength by 53.5%. These enhancements in the tensile and bending strengths may be attributed to the filling of GO in nano-sized colloidal pores and bridging over cracks. Moreover, a pore solution rich in calcium ions converts GO nanosheets into GO paper, producing stronger reinforcement. This project lays the foundation for other researchers and practitioners to better understand and apply the novel GO-cement composite with improved mechanical properties in the design of structures.

Nanomaterials are currently one of the trending research topics in material science. Due to a larger surface area, size, aspect ratios, and superior mechanical properties, the nanomaterials can be beneficial in the hydration process and nano-pore filling activities. Graphene oxide is one such nanomaterial with one its side in nanoscale, and other two sides are in larger scale. Because of the presence of oxygen functionalities, the graphene oxide can be easily dispersed in the aqueous solution when compared to other nanomaterials. Due to increase in traffic condition and environmental impacts, the pavements are not performing up to the design life. The current investigation is about the use of graphene oxide as cement additive and checking its suitability for the pavement application. In this study, polycarboxylate-based superplasticizer is used to improve the adhesion and dispersion property of the graphene oxide. The graphene oxide is added in the dosages like 0.05, 0.1, 0.15, and 0.2% by weight of cement. Number of tests has been conducted to analyze the impact of additive. The workability of graphene oxide concrete gradually decreases with the increase in its dosage, and the loss of workability is not so significant. The mechanical properties of concrete like compressive, flexural, and tensile strength are greatly increased with the addition of 0.15% graphene oxide, which is found out to be optimum dosage. The percentage increase in flexural strength is more than the percentage increase in compressive strength at 7 and 28 days. The percentage improvement in early strength is more when compared to later percentage improvement. SEM images show, with the presence of graphene oxide, there is a formation of dense microstructure. The overall test result shows that graphene oxide can be used in pavement quality concrete.

28 - Reinforcing cementitious composites with graphene oxide for enhanced mechanical performance: Prospects and challenges

Organic–inorganic hybrid coating (poly(methyl methacrylate)/monodisperse silica)

Tensile Response of Al-Based Nanocomposites

Spontaneous emulsification of 3-(trimethoxysilyl) propyl methacrylate (TPM) can produce complex and active colloids, nanoparticles, or monodisperse Pickering emulsions. Despite the applicability of TPM in particle synthesis, the nucleation and growth mechanisms of TPM emulsions are still poorly understood. We investigate droplet formation and growth of TPM in aqueous solutions under quiescent conditions. Our results show that in the absence of stirring the mechanisms of diffusion and stranding likely drive the spontaneous emulsification of TPM through the formation of co-soluble species during hydrolysis. In addition, turbidity and dynamic light scattering experiments show that the pH modulates the growth mechanism. At pH 10.1, the droplets grow via Ostwald ripening, while at pH 11.5, the droplets grow via monomer addition. Adding surfactants [Tween, sodium dodecyl sulfate (SDS), or cetyltrimethylammonium bromide] leads to <100 nm droplets that are kinetically stable. The growth of Tween droplets occurs through addition of TPM species while the number density of droplets is kept constant. In addition, in the presence of the ionic surfactant SDS, electrostatic repulsion between the solubilized TPM species and SDS leads to a significant increase in the number density of droplets as well as additional nucleation events. Finally, imaging of the solubilization of TPM in capillaries shows that in the absence of a surfactant, TPM hydrolysis is likely the rate-limiting step for emulsification, whereas the presence of silica particles in the aqueous phase likely acts as a catalyst of TPM hydrolysis. Our experiments highlight the importance of diffusion and solubilization of TPM species in the aqueous phase in the nucleation and growth of droplets.

The hybrid polymer precursor was synthesized from monomer of 3-(trimethoxysilyl) propyl methacrylate (TMSPMA) using sol-gel method and doped with inhibitor of Cerium Nitrate Hexahydrate with a concentration of 0.2%. The synthesized material was coated on a carbon steel surface by solution casting technique and followed by a photopolymerisation process. Corrosion tests were performed by using Electrochemical Impedance Spectroscopy (EIS) in 3.5% NaCl at the critical temperature of 75°C. Result of EIS data and their fitting analysis using an equivalent circuit model shows that a coating of poly(TMSPMA)-Cerium on the surface of carbon steel form a layer of protection and caused increasing of impedance value significantly. The impedance is higher compared to the carbon steel that coated with poly(TMSPMA) only.

A multi-component acrylate-based copolymer system especially designed for application as ocular lenses is developed through free-radical, bulk polymerization of a system containing hydroxyethyl methacrylate, methyl methacrylate, triethylene glycol dimethacrylate, dimethyl itaconate, 3-(trimethoxysilyl) propylmethacrylate, Polyhedraloligomeric silsesquioxane-acrylate (POSS-acrylate) and AIBN as an initiator. The progress of the reaction was monitored by Fourier transform infrared spectroscopy (FTIR). The effect of increasing concentration of the components on the hardness of the synthesized lenses was measured by Shore Durometer before and after immersion in PBS solutions. Extraction test method was performed to analyze the biocompatibility of the fabricated lenses. In this research the Taguchi method was employed to achieve the optimal hardness property which plays a critical role in final application of the lens materials. The Taguchi trial for ocular lens hardness was configured in an L16 orthogonal array, by five control factors, each with four level settings. The results showed that 3-(trimethoxysilyl) propyl methacrylate decreases and 2-hydroxyethylmethacrylate increases, polyhedraloligomeric silsesquioxane with a cage-like structure, methyl methacrylate and dimethyl itaconate increase the hardness. Proliferation and growth of the cells showed that there is no toxic substance extracted from the lenses which can interfere with the cell growth.

3-(trimethoxysilyl)propyl methacrylate was grafted into alkali treated poly(vinylidene fluoride) (PVDF) using free radical polymerization. 1H NMR, IR and DSC spectra of the modified polymer showed that double bonds were produced on PVDF and that 3-(trimethoxysilyl)propyl methacrylate was successfully grafted to PVDF. The membranes prepared using the grafted PVDF showed higher flux and better mechanical property than the pure PVDF membranes.