Styrene-butadiene Rubber Latex Research Articles

Multiple Stress Creep and Recovery Behavior of SBR-Modified Bitumen Emulsions

Abstract The effect of two grades of styrene-butadiene rubber (SBR) at 2, 4, 6, and 8 wt. % on the deformation behavior of cationic polymer-modified bitumen emulsion by a multiple stress creep and recovery test at three different temperatures (58°C, 68°C, and 78°C) was investigated. It was observed that increasing SBR latex content leads to a decrease in nonrecoverable creep compliance (Jnr) of the bituminous residue, whereas increasing temperature leads to an increase in Jnr. The results also revealed that reduction in Jnr is not remarkable for polymer content higher than 6 wt. %. Furthermore, comparing the effect of different SBRs revealed that at equal polymer content, the Jnr of SBR-modified bitumen emulsion residue was found to be twice that of a branched carboxylated styrene-butadiene rubber (X-SBR)–modified one. At the same polymer modification rate and temperature, X-SBR can be used for higher traffic levels compared to an SBR-modified bitumen emulsion.

Styrene-Butadiene Rubber by Miniemulsion Polymerization Using In Situ Generated Surfactant.

An alternative approach for the synthesis of styrene butadiene rubber (SBR) copolymer latexes was explored in order to obtain low gel fractions and high solid contents. The ultra-turrax-assisted miniemulsion stabilized by in situ surfactant generation was adopted as the main strategy since this technique can inhibit the eventual presence of secondary nucleation producing polybutadiene particles and also control the cross-linking degree. Styrene monomer was first miniemulsified using an ultra-turrax and in situ generated surfactant using either hexadecane (HD) or octadecyl acrylate (ODA) as the hydrophobe. Dynamic light scattering (DLS) measurements of droplet size indicated faster stabilization and the production of smaller droplet diameters ca. 190 nm (PdI = 0.08) when employing in situ generated potassium oleate (K-Oleate) in comparison to SDS-based miniemulsions. High butadiene-level SBR latexes with ca. 50% solids content, a glass transition temperature (Tg) of −52 °C, and a butadiene to styrene weight ratio of 75:25, were then obtained using the miniemulsion droplets as seeds. Turbiscan and DLS measurements revealed a very stable resulting latex with SBR particle diameter of ca. 220 nm and a low polydispersity index (PdI). Secondary nucleation was prevented as indicated by the low Np/Nd value. Cryo-TEM images showed a narrow distribution of particle size as well as the absence of agglomeration. The gel content was below 10% when tert-dodecyl mercaptan (t-DM) was used as chain transfer agent (CTA).

Polymer-inorganic hybrid colloids for ultraviolet-assisted direct ink write of polymer nanocomposites

Inorganic-polymer hybrid colloids present a modular and tunable route to fabricate polymer nanocomposites from low viscosity precursors; however, their use in additive manufacturing remains limited. This manuscript describes photocurable “hybrid colloids” to enable layered fabrication of elastomeric nanocomposites, i.e., combination of continuous-phase photocrosslinking chemistry with hybrid colloids of water-dispersible silica nanoparticles and styrene-butadiene rubber (SBR) latex particles. Varying the relative concentrations of polymeric and inorganic particles afforded precise tuning of filler loading in the final nanocomposite and introduced a bimodal particle size distribution with desirable rheological behavior for extrusion-based additive manufacturing. Specifically, ultraviolet-assisted direct ink write (UV-DIW) processing of the photocurable hybrid colloid pastes generated free-standing green bodies, which contained a combination of SBR and silica nanoparticles. Subsequent drying of the green bodies allowed SBR particle coalescence and penetration through the scaffold and surrounding the silica nanoparticles, which yielded a semi-interpenetrating network (sIPN) nanocomposite. Facile tuning of silica concentrations in the hybrid colloid enabled tuning of both the colloidal ink rheology and mechanical properties of the final sIPN nanocomposites to achieve additive manufacturing of silica-SBR nanocomposites with ultimate tensile strains exceeding 300 % and ultimate tensile strengths above 10 MPa.

Comparative study of hybrid fiber cementitious composites

Different types of fibers impart specific characteristics to concrete, including crack bridging, early age crack resistance, ductility, toughness, strength, and loss of workability. It seems that if these fibers are combined, then specific characteristics of each fiber may be imparted to concrete and the desired characteristics of the concrete composite may be achieved. Thus, this investigation has been conducted to study the properties of concrete composites composed of four different types of fibers used singly or in hybrid form. The effectiveness of hybrid fibers in cementitious composites to achieve better characteristics; strengths, toughness, workability, and cost, was investigated and compared. Composites made of carbon fiber, plain steel fiber, polypropylene fiber, and glass fiber and their hybrid combinations (2, 3 and 4 fibers mixed), at constant volume of fiber 1.25%, along 4% styrene-butadiene rubber latex and 1.5% superplasticizer, are prepared and tested. The composites are compared and investigated for their feasibility in terms of their properties and cost. The comparison showed the suitability of some bi-hybrid composites, and incompatibility of tri-hybrid and tetra-hybrid composites in terms of effectiveness and feasibility.

Carbon dots: Fluorescence active, covalently conjugated and strong reinforcing nanofiller for polymer latex

This paper reports a unique approach to the synthesis of rubber nanocomposites in which functionalized carbon dots (cdots) are covalently bonded to functionalized rubber latex. In this approach, the cdots are functionalized with amine (-NH2) groups that are capable of chemically binding with the carboxylated styrene butadiene rubber (XSBR) latex possessing acid (-COOH) groups. Pristine cdots are characterized using powder X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), fluorescence spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy and high resolution transmission electron microscopy (HRTEM). The -COOH groups of XSBR latex has been covalently appended with the -NH2 groups of cdots using N-hydroxysuccinimide (NHS) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) mediated amide coupling. FTIR spectroscopy and XPS endorse the covalent conjugation of cdots with XSBR latex. Remarkable increase in the maximum tensile stress and elongation at break of XSBR has been observed by addition of very less amount cdots. XSBR containing 0.8 parts per hundred of rubber (phr) of cdots shows a maximum tensile stress value which is around 235% higher in comparison to neat XSBR. Dynamic mechanical analysis (DMA) shows the reduction in the tan δ peak height and increase in the tan δ peak temperature of XSBR by incorporation of cdots. Also, XSBR containing 0.8 phr of cdots shows an elastic modulus (E’) value which is around 70% higher in comparison to neat XSBR. The maximum degradation temperature (Tmax) and the onset of degradation temperature (Ti) of XSBR containing 1 phr of cdots is around 10 °C and 8 °C higher when compared to neat XSBR. The prominent improvement in the overall properties of XSBR latex by addition of cdots has been attributed to the enhanced cross-linking introduced by the covalently conjugated cdots in XSBR matrix. XSBR-cdots nanocomposite has also been found display good photoluminescence properties due to the presence of cdots, which are confirmed by UV–Vis spectroscopy and fluorescence spectroscopy studies. Morphology of XSBR-cdots nanocomposites has been studied using HRTEM and atomic force microscopy (AFM).

Qualitative assessment of interfacial bonding in 3D printing concrete exposed to frost attack

The 3D printing technology is a novel construction process to build concrete structures layer-by-layer based on computer digital programs. The main objective of this research program is to develop a testing protocol that replicates the successive placement of mortar layers and satisfactorily measures the effect of repeated freeze/thaw (F/T) cycles on durability and interfacial bond strengths. Three mortar series made with different binder and mixing water contents are tested; the consistency of mixtures was adjusted to allow proper extrusion using a laboratory 3D printer. Particular emphasis was placed to compare the efficiency of air-entraining agent (AEA) and styrene-butadiene rubber (SBR) latexes to protect mortars against deterioration due to frost attack. The incorporation of SBR was found more efficient than AEA to mitigate the drop in bond strength due to F/T cycles, given the enhanced flexibility of the polymer-modified mortars that accommodate the deformations and stresses created along the interfaces. The pull-off test results obtained were successfully validated using specimens generated from the laboratory 3D printer.

Mechanical properties and durability of rubberized and SBR latex modified rubberized concrete

This paper analyses how rubber waste, used as replacement of fine aggregate in concrete mixes, affects mechanical properties and durability of concrete: freeze-thaw resistance, water absorption by immersion, and sulphate resistance. Concrete was modified by carboxylated styrene butadiene rubber (SBR) latex to get better bonding properties between rubber and hardened cement paste. Control specimens were made of concrete mix without crumb rubber. Scrap tyre rubber powder (crumb rubber – CR) of fraction 0/1mm and 1/2mm was used as fine aggregate. CR was used to replace a portion of fine aggregate at 5% of the total aggregate content. CR of fraction 0/1mm was found to improve freeze-thaw resistance: freeze-thaw resistance test results were similar to those of concrete with traditional air entrainment systems. On the contrary, coarser rubber particles of fraction 1/2mm had a negative effect on freeze-thaw resistance of concrete. These findings can be explained by the smoother texture and a more regular shape of coarse rubber particles up to 2 mm in size and the rougher texture and irregular shape of fine particles up to 1 mm in size. A complex profile of rubber particle surface results in higher volume of air voids, higher closed porosity and higher freeze-thaw resistance of concrete modified with crumb rubber. The test results confirmed that concrete modified with crumb rubber of smaller fraction had higher closed porosity and higher freeze-thaw durability factor Kf. The results also confirmed that Kf values calculated from concrete porosity parameters can be conveniently used to predict freeze-thaw resistance and durability of concrete. The tests have shown that the modification of concrete with rubber waste has no positive effect on sulphate resistance, compressive strength and modulus of elasticity.

Performance Characterization of Waterborne Epoxy Resin and Styrene–Butadiene Rubber Latex Composite Modified Asphalt Emulsion (WESAE)

Neat asphalt emulsions have poor physicochemical properties. In order to endow neat asphalt emulsions with excellent physicochemical properties and broaden their application as pavement, this study adopted the composite modification method using waterborne epoxy resin (WER) and styrene–butadiene rubber (SBR) latex. Firstly, a waterborne-epoxy–SBR composite modified asphalt emulsions (WESAEs) with different amounts of WER were prepared, and the storage stability, workability, and residual properties were characterized with a series of tests. Then, the performance of the WESAEs was comprehensively evaluated by multiobjective gray target decision-making method, through which the optimal amount of WER in WESAE was determined. Lastly, the modification mechanism of WER was revealed by Fourier-transform infrared spectroscopy test. The results show that the incorporation of WER improves the high-temperature performance, thermal stability, rheological property, and adhesion of the SBR modified asphalt emulsion (SBRAE) residues. However, an excessive amount of WER will adversely affect the storage stability, particle distribution uniformity, and workability of the WESAE binder. The WESAE with 3% WER showed the best comprehensive performance; thus, the optimal amount of WER is 3% of the weight of the WESAE. Additionally, modification of the SBRAE by WER is a physical blending process, meaning no chemical reaction occurs in the blending process.

Strength and Durability of Styrene Butadiene Latex Modified Concrete with Silica Fume

This paper discussed the properties of styrene butadiene rubber (SBR) latex modified concrete. The latex modified concrete using SBR latex were prepared with various polymer-binderratios and tested for compressive strength, flexure strength, elastic modulus and rapid chloride penetration test. Latex contents were varied as 5, 10 and 15 percentages by mass of binder (cement and silica fume). The effect of the polymer-binder ratio on the properties of latex modified concrete was examined. It was concluded from the test results that the compressive strength and elastic modulus decrease with polymer binder ratio and flexural strength increasing with polymer binder ratio. Addition of latex reduces the chloride ion penetration due to latex film formation..

Durability of polymer-modified lightweight flowable concrete made using expanded polystyrene

Lightweight self-consolidating concrete (LWSCC) intended for structural and repair applications combines the advantages of improved workability and reduced dead loads resulting from the structure self-weight. This investigation evaluates the coupled effects of expanded polystyrene (EPS) and styrene-butadiene rubber (SBR) latexes on durability-related properties of LWSCC weighing between 1870 to 2360 kg/m3. The water-to-binder ratio (w/b) was regulated to ensure similar compressive strengths. Test results showed that the transport properties including sorptivity, corrosion, and chloride ion penetration were pretty similar to the control normal-weight concrete, despite the decrease in density. This was attributed to a combination of phenomena such as lower w/b that refines the concrete microstructure, EPS particles that function as internal barriers, and presence of SBR polymers that create dispersed network of impermeable films. The incorporation of SBR was beneficial to improve bonding strengths of composite slabs, especially when exposed to repeated freeze/thaw cycles. Compared to normal-weight concrete, the resistance to chemical attack improved when LWSCC is prepared with reduced w/b and/or SBR additions. Different regression models are proposed to predict the concrete durability as a function of w/b, EPS, and SBR rates.

Mechanical and permeability properties of polymer-modified concrete using hydrophobic agent

Three types of polymer modifier used in concrete (styrene-butadiene rubber latex, polyacrylic ester emulsion and organic silicon waterproof agent) were employed to investigate their effects on the compressive strength, capillary water absorption and chloride ion permeability of concrete. Results show that the incorporation of polymer modifier reduces the compressive strength, and fly ash (FA) can improve this adverse effect. All three polymer modifiers can significantly reduce the permeability of concrete, and the effect is more significant at high water-to-binder ratio. Among them, the compressive strength of organic silicon waterproof agent modified concrete is the most similar to that of ordinary concrete, and the sorptivity coefficient is relatively low, even at higher dosages. In addition, with the prolongation of the curing age, the impermeability of polymer-modified concrete mixed with FA reaches the best. The addition of FA can not only achieve economic and environmental benefits, but also cooperate with the polymer in the concrete, thereby improving the waterproofness of the concrete.

3D Printing Latex: A Route to Complex Geometries of High Molecular Weight Polymers.

Vat photopolymerization (VP) additive manufacturing fabricates intricate geometries with excellent resolution; however, high molecular weight polymers are not amenable to VP due to concomitant high solution and melt viscosities. Thus, a challenging paradox arises between printability and mechanical performance. This report describes concurrent photopolymer and VP system design to navigate this paradox with the unprecedented use of polymeric colloids (latexes) that effectively decouple the dependency of viscosity on molecular weight. Photocrosslinking of a continuous-phase scaffold, which surrounds the latex particles, combined with in situ computer-vision print parameter optimization, which compensates for light scattering, enables high-resolution VP of high molecular weight polymer latexes as particle-embedded green bodies. Thermal post-processing promotes coalescence of the dispersed particles throughout the scaffold, forming a semi-interpenetrating polymer network without loss in part resolution. Printing a styrene-butadiene rubber latex, a previously inaccessible elastomer composition for VP, exemplified this approach and yielded printed elastomers with precise geometry and tensile extensibilities exceeding 500%.

Effect of Epoxy Resin Emulsion on the Mechanical Properties of Oil Well Cement‐Based Composites

Oil well cement is a brittle material, which can not ensure the long‐term sealing integrity of oil and gas wells when used in cementing operations directly. As a kind of polymer emulsion material, epoxy resin emulsion has a bright future for improving the properties of the cement slurry. Epoxy resin emulsion was added to oil well cement and its workability and mechanical properties were studied, the stress‐strain behavior of cement samples was evaluated, and the microstructure was observed by scanning electron microscope (SEM) and X‐ray diffraction (XRD). The results show the epoxy resin emulsion used in oil well cement will affect the fluidity, but the rheological property of cement slurry with different content of resin meets the construction requirements. The resin reduces the water loss of cement paste and has no adverse effect on the thickening time. The compressive strength of cement stone decreases with the increase in resin content. When the content of resin is 6%, the flexural strength and impact strength of the cement sample are the largest, and 50.7% and 20.2% higher than that of the specimen without resin, respectively, after curing for 28 days. Further comparison shows that epoxy resin emulsion can improve the mechanical properties of oil well cement better than styrene‐butadiene rubber latex. Meanwhile, the resin obviously improves the deformability and decreases the elastic modulus of cement stone. Compared with pure cement, resin cement slurry has no extra hydration products, but the formation of hydrated calcium silicate is inhibited. The microstructure shows that the resin forms a polymer film in the cement matrix and interweaves with cement hydration products, thus improving the flexibility of cement paste.

Rheological, mechanical, and abrasion characteristics of polymer-modified cement mortar and concrete

The settlement of fresh concrete or improper operation during construction usually makes the water to cement (w/c) ratio of the cement mortar on the concrete pavement surface higher than designed, which may influence the abrasion resistance of concrete pavement. This study firstly tried to establish relationships between abrasion of hardened cement mortar and rheological characteristics of fresh cement mortar in the laboratory. Secondly, a polymer-modified cement mortar was developed with carboxyl styrene butadiene rubber latex added to the cement mortar. Its rheological properties in mixing, mechanical properties, and abrasion were investigated. It is found that the polymer-modified cement mortar has a much better abrasion resistance and flexural strength while lower compressive strength than cement mortar. A stronger correlation was observed between flexural strength rather than compressive strength and abrasion resistance of cement mortar. The proposed polymer-modified concrete also exhibited good abrasion resistance.

Effect of quality of recycled aggregates on bond strength between concrete and embedded steel reinforcement

The use of recycled concrete aggregate (RCA) in structural applications considerably increased. The main objective of this paper is to assess the effect of parent concrete (PC) quality on RCA properties including concrete durability and bond to steel reinforcement. Four RCA types are considered; three were sourced from 13, 42, and 62-MPa compressive strength (f’c) normal-density PC, while the fourth type was derived from lightweight PC. Test results showed that the PC quality has direct influence on the transfer of stresses and ultimate bond strengths to embedded rebars. The incorporation of styrene-butadiene rubber (SBR) latexes was found efficient to mitigate the drop in concrete mechanical properties including f’c, splitting tensile strength, electrical resistivity, and ultimate bond strength to embedded steel. The experimental data are compared to the design bond strengths specified in international codes such as ACI 318-17, European Code EC-2, and fib Model Code MC2010.

Parametric study on polymer-modified pigmented cementitious overlays for colored applications

Limited studies addressed the concurrent effects of iron oxide pigments (IOPs) and styrene-butadiene rubber (SBR) latexes on properties of self-leveling mortars (SLMs) intended for decorative and aesthetic overlays. Different mortar series prepared with 0.45–0.6 water-to-cement ratio (w/c), 2%–8% yellow or red colored IOP, and 5%–15% SBR are investigated. Test results showed that fresh SLM rheological properties including yield stress and plastic viscosity are highly affected by the IOP fineness, morphology (spherical vs. elongated), and concentration. Mixtures incorporating low IOP rates (i.e., less than 4%) exhibited relatively higher strengths and bond to existing substrates. The flexural and bonding strengths remarkably improved with SBR additions, given the stronger interfacial bonds created between such polymers and the cementitious matrix. Particular emphasis was placed to develop regression models and charts that enable predicting key SLM properties including color coordinates, rheological properties, flexural/compressive strength, and bond to existing substrates.

Bond Properties of Polymer-Modified Lightweight Self-Consolidating Concrete Containing Expanded Polystyrene

Abstract Limited studies addressed the effect of styrene-butadiene rubber (SBR) latexes on bond properties of lightweight self-consolidating concrete (LWSCC) containing expanded polystyrene (EPS). Different concrete series containing up to 20 % EPS are tested in this program; the resulting density ranged from 1,870 to 2,350 kg/m3. The SBR was incorporated at various rates, whereas the water-to-binder ratio (w/b) was adjusted depending on EPS additions to maintain a fixed compressive strength of 42 ±4 MPa. The high-range water reducer and viscosity-modifier were regulated to secure the desired LWSCC workability and stability requirements. Test results showed that the incorporation of EPS decreases the pull-off bond strength to existing substrates as well as the ultimate bond strength to embedded steel bars, given the weaker concrete skeleton and stiffness that favor microcrack propagation during tensile loading. The reduction in w/b was efficient to strengthen the matrix and improve the pull-off bond, particularly for mixtures incorporating SBR additions. The improved ultimate bond strength that was due to decreased w/b was attributed to less bleed water and fewer shrinkage cracks at the vicinity of the reinforcing bars as well as higher concrete crushing strength between the steel ribs. A series of regression statistical models are developed to simplify predicting mechanical and bond properties of SBR-modified EPS-based LWSCC mixtures.

Synthesis, Characterization, Environmental Properties and Mechanical Studies of SBR-Nano Aluminum Oxide Composites

Background: Rubber or nano aluminum oxide composites may be considered as potential materials in mechanical applications because of the adaptability of polymer properties of nanometric substances. Rubber nano-composite is prepared by using the emulsion polymerization method. Mechanical properties and environmental resistance properties are evaluated for a better rubber-filler interaction. Purpose: In this examination, the Raman spectroscopy and the mechanical properties of nanocomposites are based on Styrene-Butadiene rubber (SBR) and were explored within the sight of nano aluminum oxide additive. The nano-composites were prepared by mechanically mixing and utilizing two-roll mills. Nano aluminum oxide particle suspensions were added to SBR and the abrasion and spectral properties were overviewed. Materials and Methods: Nano aluminum oxide, 2, 2’- dithiobis, tetramethyl thiuram disulfide, N, N’- Diphenyl P- phenylenediamine and SBR latex were used for analysis. SBR nano-composite was obtained by using the emulsion polymerization method. Results: Mechanical test outcomes demonstrated the improvement in tensile strength, elongation, and tear resistance. Abrasion test results demonstrated that nano aluminum oxide particles could improve the abrasion resistance of SBR matrix because of the good properties of nano aluminum oxide particles. The strengthening capacity of the fillers resulted in noteworthy upgrades in the properties of polymer framework at extremely low filler loadings when contrasted with conventional fillers. In this work, we concentrate on Raman spectroscopy and mechanical properties by including filler content within a low loading amount. The collection idea of the combined rubber nano-composite was built up by using scanning electron microscopy (SEM). The impact of nanoparticles in the polymer network has been assessed for the SBR-nano aluminum oxide from the TEM investigation. Thermogravimetric analysis (TGA and DTA) was also examined. Ozone resistance was studied to elucidate periodic observations of the surface of samples, which were made for crack initiation. The samples were exposed for a longer time. Flame resistance was studied to measure the ease of extinction of a flame and four ratings were possible, depending upon the burning time and the presence of flaming drips. Conclusion: The present study highlights the emulsion polymerization method, where the environmental resistance performance of rubber nano-composites is found to be improved and the thermal and mechanical properties are also enhanced.

Strength Development Characteristics of SBR-Modified Cementitious Mixtures for 3-Demensional Concrete Printing

The properties of normal cementitious mixtures currently employed to the construction projects cannot be used to the three-dimensional concrete printing technology. This study experimentally investigated the compressive and flexural strength development of styrene-butadiene rubber (SBR)-modified cementitious mixtures for use as basic three-dimensional concrete printing (3DCP) materials. The SBR/cement ratio was a variable of the mix proportion used to produce cast and printed specimens. Experiments were conducted using these specimens to determine the compressive and flexural strength levels of the SBR-modified cementitious mixtures. The results indicated that the compressive strengths of the SBR-modified cementitious mixtures proposed in this study were never less than those of existing 3D concrete printing materials previously introduced for 3DCP applications. It was confirmed that the addition of SBR latex effectively improved the strength of the cementitious mixtures because the relative compressive and flexural strengths increased with increases in the SBR/cement ratio. Moreover, the higher early (i.e., 1-day) strength indicates that the SBR-modified cementitious mixtures would be advantageous to the 3DCP process. However, the compressive and flexural strengths of the printed specimens were weaker than those of the cast specimens.

Influence of Different Modifiers on Bonding Strength and Rheological Performance of Bitumen Emulsion.

Styrene butadiene rubber latex (SBR), waterborne epoxy adhesive (WE) and colloidal silica sol (SiO2) were used to prepare modified bitumen emulsion for cold mix asphalt. The modification effects of the individual modifiers and the combination of these modifiers were investigated by using bonding strength and dynamic shear rheological property. Test results showed that the modifier dosage helped to balance the performance of modified bitumen emulsion by improving its bonding strength without compromising its rheological properties. The critical dosage at which the peak bonding strength occurred was 4%, 12% and 4% for SBR, WE and SiO2 respectively. Improved rheological performance on the master curves was well distinguished, in particular, by increased complex modulus and reduced phase angle at the low frequency region. Abrupt changes, especially on phase angle occurred when the modifier dosage was beyond 12%. The measured ratio between bonding strength and complex shear modulus could vary ranging from 10−2 to 102. Highly-modified bitumen emulsion with good adhesion, rheology and compatibility can be prepared by using the combination of SBR, WE and SiO2. It is important to carefully select the type and dosage of modifier for a particular combination to optimize the performance of modified bitumen emulsion.