Effect of coating type on the mechanical performance of warp-knitted fabrics and cement-based composites

2018 ◽  
Vol 52 (19) ◽  
pp. 2563-2576 ◽  
Author(s):  
Till Quadflieg ◽  
Sebastian Leimbrink ◽  
Thomas Gries ◽  
Oleg Stolyarov

High-performance textiles are used for reinforcing concrete structural parts. This paper presents a technique for producing coated weft-inserted warp-knitted fabrics for concrete applications. Three types of reinforced fabrics differing in coating type and composed of alkali-resistant-glass rovings resulting in a cement composite matrix were produced. The investigated coatings include potassium silicate, carboxylated styrene butadiene rubber and epoxide. The mechanical properties of the developed fabrics and cement composites were determined according to the coating type. Thereafter, the mechanical performance of the warp-knitted reinforced fabrics was investigated using tensile tests. Finally, the properties of the composites were examined according to the coating type using a four-point bending test. The results of the characterization of the coated weft-inserted warp-knitted reinforced fabrics and cement composites based on them are presented and discussed. It is shown that the coating material has high influence on the composite properties. Samples with potassium silicate showed highest strength at the limit of proportionality, while samples with epoxide showed the highest flexural strength.

2021 ◽  
Author(s):  
Joyeeta Ghosh ◽  
Sakrit Hait ◽  
Soumyajit Ghorai ◽  
Dipankar Mondal ◽  
Gert Heinrich ◽  
...  

Abstract The prevention of detrimental effects to environment, owing to generation of a huge amount of rubber wastes, is a big challenge across the globe that warrants a thorough investigation of recycling and reuses waste of rubber products. In this spirit a sustainable development of a devulcanization process along with the production of value added devulcanized rubber is a task of hours. The present work describes a simultaneous devulcanization and chemical functionalisation process of waste solution styrene butadiene rubber (S-SBR). This kind of rubber is generally used as the main polymer component in silica filled tread rubber compounds for high-performance passenger car tyres. As-grown ethoxy groups on the functionalized devulcanized styrene butadiene rubber (D-SBR) are exploited for the coupling between silica and the devulcanized rubber chains. We compare the mechanical and dynamic mechanical performance of D-SBR with that of virgin SBR control composites. Covalently bonding interfaces developed from the pendent ethoxy groups of D-SBR and silanol groups on the silica surface offer a competitive and promising performance of the D-SBR based composites. We conclude that the present approach can be further utilized for the large-scale production of different rubber products with satisfied elastomeric performance.


2021 ◽  
pp. 009524432110290
Author(s):  
Leandro Hernán Esposito ◽  
Angel José Marzocca

The potential replacement of a treated residual aromatic extract mineral oil (TRAE) by a highly epoxidized soybean oil (ESO) into a silica-filled styrene-butadiene rubber compound was investigated. In order to determine if ESO compounds performance are suitable for tread tire applications, processing properties cure and characteristics were evaluated. The impact of ESO amount on the silica dispersion was confirmed by Payne Effect. The presence of chemical or physical interactions between ESO and silica improves the filler dispersion, enabling the compound processability and affecting the cure kinetic rate. An adjusted rubber compound with 2 phr of ESO and 2 phr of sulfur presented the higher stiffness and strength values with lower weight loss from a wear test compared with TRAE compound at an equal amount of oil and curing package. Furthermore, wet grip and rolling resistance predictors of both compounds gave comparable results, maintaining a better performance and reducing the dependence of mineral oil for tire tread compounds.


2021 ◽  
Author(s):  
Jie Hu ◽  
Zhengqing Kong ◽  
Ke Liu ◽  
Jinli Qin ◽  
Yuhong Tao ◽  
...  

Abstract The surface functionalization of CNCs and the construction of strong interfacial adhesion between CNCs and rubber matrix are effective way to achieve high performance rubber/CNCs nanocomposites. Herein, carboxylation of sulphated cellulose nanocrystals (CNC-OSO3H) was conducted in aqueous medium by using citric acid as modifier. Large amount of carboxyl groups was successfully grafted on the surface of CNC-OSO3H, which endows the carboxylated CNC-OSO3H (abbreviate as CNC-CA) with higher chemical reactivity and thermal stability. Subsequently, carboxylated styrene butadiene rubber (XSBR)/CNC-CA nanocomposites with dual crosslinking design were prepared by using polyethylene glycol diglycidyl ether (PEGDE) as the crosslinking agent and CNC-CA as the reinforcing fillers. FTIR investigation found that in the obtained nanocomposites, the carboxyl groups on CNC-CA and XSBR formed hydrogen bonds (physical crosslinking) with each other, and the carboxyl groups formed covalent bond with the epoxy group on PEGDE simultaneously. The coexistence of physical and chemical crosslinking improved the interface compatibility between CNC-CA and XSBR matrix, accelerated the homogenous dispersion of CNC-CA and realized the crosslinking of the matrix itself. As expected, XSBR/CNC-CA nanocomposites with dual crosslinking network showed remarkable enhancement in tensile strength (up to 500%), modulus (up to 151%), work of fracture (up to 348%). This work provides both a facile and green approach to obtain carboxylated CNCs and a convenient method for the preparation of high-performance rubber nanocomposites with multiple interactions.


Author(s):  
Genadijs Sahmenko ◽  
Sandis Aispurs ◽  
Aleksandrs Korjakins

Traditionally, sculptural and decorative elements of building facades are created from mortar mixes based on lime, gypsum or Portland cement. Generally these materials have porous and permeable structure, which determines their accelerated degradation, especially in the aggressive environment of modern cities. High performance cement composites (HPCC) have been considered for production and restoration of sculptural elements in historical buildings. For this purpose, fine-graded, multi-component and highly workable mixes were elaborated. Mix compositions were modified with micro-fillers, plasticizing and stabilizing admixtures, as well as fibers to improve material ductility and control shrinkage cracking. Basic mechanical properties and durability (such as water absorption, frost resistance) were determined and two types of HPCC were compared (>50 MPa: HPCC and >120 MPa: UHPCC). It has been confirmed that cement composite mixes are characterized by self-consolidating effect, high compressive strength, extremely high resistance versus freezing and thawing cycles and low water absorption. Surface quality was evaluated and initial water absorption (tube tests) were performed for laboratory samples and real sculptural elements after 5 years of exploitation. The results confirmed good potential for using HPCC for creating more attractive and durable architectural shapes and façade elements compared to elements made using traditional cement and lime mortar.


ACS Omega ◽  
2019 ◽  
Vol 4 (8) ◽  
pp. 13189-13199 ◽  
Author(s):  
Alex Sinclair ◽  
Xiaoyi Zhou ◽  
Siwakorn Tangpong ◽  
Dilpreet S. Bajwa ◽  
Mohiuddin Quadir ◽  
...  

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1527
Author(s):  
Liwei Li ◽  
Haijun Ji ◽  
Hui Yang ◽  
Liqun Zhang ◽  
Xinxin Zhou ◽  
...  

In response to increasingly stringent requirements for the sustainability and environmental friendliness of the rubber industry, the application and development of bio-based elastomers have received extensive attention. In this work, we prepared a new type of bio-based elastomer poly(dibutyl itaconate-butadiene) copolymer (PDBIB) nanocomposite using carbon black and non-petroleum-based silica with a coupling agent. Using dynamic thermodynamic analysis (DMTA) and scanning electron microscope (SEM), we studied the effects of feed ratio on dynamic mechanical properties, micro morphology, and filler dispersion of PDBIB composites. Among them, silica-reinforced PDBIB60 (weight ratio of dibutyl itaconate to butadiene 40/60) and carbon black-reinforced PDBIB70 (weight ratio of dibutyl itaconate to butadiene 30/70) both showed excellent performance, such as tensile strength higher than 18 MPa and an elongation break higher than 400%. Compared with the widely used ESBR, the results showed that PDBIB had better rolling resistance and heat generation than ESBR. In addition, considering the development of green tires, we compared it with the solution polymerized styrene–butadiene rubber with better comprehensive performance, and analyzed the advantages of PDBIB and the areas to be improved. In summary, PDBIB prepared from bio-based monomers had superior performance and is of great significance for achieving sustainable development, providing a direction for the development of high-performance green tire and holding great potential to replace petroleum-derived elastomers.


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4865
Author(s):  
Elżbieta Horszczaruk ◽  
Paweł Łukowski ◽  
Cyprian Seul

In recent years, a nano-modification of the cement composites allowed to develop a number of new materials. The use of even small amount of nano-admixture makes possible not only to improve the physico-mechanical properties of the cement materials, but also to obtain the composite with high usability, optimised for the given application. The basic problem of nano-modification of the cement composites remains the effectiveness of dispersing the nanomaterials inside the cement matrix. This paper deals with the effect of the type and size of the nanoparticles on the tendency to their agglomeration in the cement matrix. The main techniques and methods of dispersing the nanomaterials are presented. It has been demonstrated, on the basis of the results of testing of three nanomodifiers of 0D type (nano-SiO2, nano-Fe3O4 and nano-Pb3O4), how the structure and properties of the nanomaterial affect the behaviour of the particles when dissolving in the mixing water and applying a superplasticiser. The nanoparticles had similar size of about 100 nm but different physico-chemical properties. The methods of dispersing covered the use of high-speed mechanical stirring and ultrasonication. The influence of the method of nano-modifier dispersing on the mechanical performance of the cement composite has been presented on the basis of the results of testing the cement mortars modified with 3% admixture of nano-SiO2.


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