Development of acrylonitrile–butadiene–styrene composites with enhanced UV stability

Aiming to develop acrylonitrile–butadiene–styrene (ABS) composites with enhanced ultraviolet stability, a series of formulations were prepared by melt compounding and evaluated by different characterization techniques. The influence of rutile titanium dioxide (TiO₂) and its combination with furnace carbon black (CB) on the viscoelastic properties of neat ABS was studied by dynamic mechanical analysis. An increase in the glass transition (T _g) dynamics ascribed to the rubbery phase as a function of exposure time was observed. A greater contribution of CB nanoparticles in combination with TiO₂ to minimize the modifications on the T _g of the butadienic component was clearly seen. Quasi-static and spectrophotometry results are in good agreement, showing the efficiency of TiO₂ submicron particles and CB/TiO₂ against photo-oxidative degradation of neat ABS. A different behaviour was observed for modified ABS/TiO₂ and ABS/CB/TiO₂ composites with light stabilizers, antioxidants and combinations of them. While the TiO₂ efficiency was enhanced by the incorporation of combinations of light stabilizers and antioxidants, poor results were observed for modified ABS/CB/TiO₂ composites as a consequence of antagonistic interactions. It was concluded that formulations of ABS/CB/TiO₂ with light stabilizers and ultraviolet absorbers are unacceptable for common applications.     

Torsional,tensile and structural properties of acrylonitrile–butadiene–styrene clay nanocomposites

Torsional and tensile behaviour of acrylonitrile–butadiene–styrene (ABS)-clay nano-composites have been investigated and correlated with morphological and rheological characterisations. Nano-composites of ABS are prepared by melt compounding with different loading levels of nanoclay (Cloisite 30B) in a twin screw extruder and have been characterised in terms of torsional, axial and impact behaviour for their application in external orthotic devices. Tensile stress strain curve of nanocomposites are investigated to quantify resilience, toughness and ductility. Torque values of the nanocomposites are observed under torsion (10°–90°) and compared with that of neat ABS. Performance of ABS under torsional load improved by addition of nanoclay. Both modulus of elasticity and rigidity are found to improve in presence of nanoclay. State of dispersion in nano-composites is investigated using conventional methods such as transmission electron microscopy (TEM), X-ray diffraction (XRD), as well as by parallel plate rheometry. Addition of clay exhibits shear thinning effect and results in increase in storage modulus as well as complex viscosity of the nanocomposites. Zero shear viscosity rises tenfold with 1–2% addition of nanoclay, indicating the formation of structural network. It is found that state of dispersion of nanoclay governs the torsional and mechanical properties in ABS-clay nanocomposites.     

Biocompatibility of epoxidized styrene–butadiene–styrene block copolymer membrane

Styrene–butadiene–styrene block copolymer (SBS) membrane was prepared by solution casting method and then was epoxidized with peroxyformic acid generated in situ to yield the epoxidized styrene–butadiene–styrene block copolymer membrane (ESBS). The structure and properties of ESBS were characterized with infrared spectroscopy, Universal Testing Machine, differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA). The performances of contact angle, water content, protein adsorption, and water vapor transmission rate on ESBS membrane were determined. After epoxidation, the hydrophilicity of the membrane increased. The water vapor transmission rate of ESBS membrane is similar to human skin. The biocompatibility of ESBS membrane was evaluated with the cell culture of fibroblasts on the membrane. It revealed that the cells not only remained viable but also proliferated on the surface of the various ESBS membranes and the population doubling time for fibroblast culture decreased.     

Plating on acrylonitrile–butadiene–styrene (ABS) plastic: a review

ABS is an engineering plastic that has butadiene part uniformly distributed over the acrylonitrile-styrene matrix. It possesses excellent toughness, good dimensional stability, easy processing ability, chemical resistance, and cheapness. However, it suffers from inherent shortcomings in terms of mechanical strength and vulnerability to environmental conditions. Furthermore, it is non-conducting and easily fretted. Plating on ABS can serve to enhance the strength and structural integrity as well as to improve durability and thermal resistance resulting in metallic properties on the ABS material. ABS is described as the most suitable candidate for plating because it is possible to deposit an adherent metal coating on it by only the use of chemical pretreatment process and without the use of any mechanical abrasion. This article aims to review the history of ABS plastics, properties of ABS, processes and mechanisms of plating, and studies of plating on ABS involving mainly eco-friendly methods of plating by discussing the literature published in recent years. The details of electroplating of ABS carried out in the authors’ laboratory are also presented.     

On styrene–butadiene–styrene–barium ferrite nanocomposites

Magnetic investigations on a nanocomposite material obtained by spinning solutions of styrene–butadiene–styrene block copolymer containing barium ferrite nanoparticles onto Si wafers are reported. The effect of the spinning frequency on the magnetic features is discussed. It is observed that the magnetization at saturation is decreased as the spinning frequency is increased as the centrifuge force removes the magnetic nanoparticles from the solution. This is supported by the derivative of the hysteresis loops, which show two components, one with a high coercive field and another with a small coercive field. Increasing the spinning frequency increases the weight of the low coercive field component. The anisotropy in the distribution of magnetic nanoparticles, triggered eventually by the self-assembly capabilities of the matrix, is revealed by the difference between the coercive field in parallel and perpendicular configuration. It is noticed that increasing the spinning frequency enhances this difference. The effect of annealing the nanocomposite films is discussed.     

Photoinitiator grafted styrene–butadiene–styrene triblock copolymer

Grafting of photoinitiator-4-maleimidobenzophenone (4-MBP) onto styrene–butadiene–styrene (SBS) triblock copolymer was carried out by free radical polymerization. The grafting ratio was evaluated by varying initiator concentrations, and the structure of grafted copolymer (SBS-g-MBP) was characterized by attenuated total reflectance infrared Fourier transform spectroscopy (ATR-FTIR), proton nuclear magnetic resonance (¹H NMR) and X-ray photoelectron spectroscopy (XPS). The results confirmed that 4-MBP was successfully grafted onto the SBS backbone. Thermal gravimetric analyzer (TGA), dynamic mechanical thermal analysis (DMTA), scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to study the thermal properties and morphology of the SBS-g-MBP. From the data of TGA, the SBS-g-MBP had better thermal stability compared with that of SBS. DMTA testing indicated that the glass transition temperature (T_g) of SBS-g-MBP was higher than that of SBS. With the aid of SEM and AFM, the structure of micro-phase separation can be observed obviously. What is more, the aggregates become smaller compared with those of pure SBS. The experiment of UV-crosslinked SBS-g-MBP revealed that the gel fraction could be facilely controlled by adjusting grafting ratio and exposure time. The results suggested that this novel grafted copolymer could be attractive for its application in biomedical materials such as medical pressure-sensitive adhesive.     

Rheology of asphalt and styrene–butadiene blends

In recent years, many authors have researched polymer-modified asphalt blends and tried to better understand the rheological behavior of these materials. In this work, the thermomechanical response of an asphalt formulation was researched trying to find better asphalt-modified blends that allow for the construction of improved asphalt roads. The experimentation included several polymer–maltene formulations developed at different polymer concentrations and temperatures where the asphaltenes of the original asphalt were removed. Such separation was carried out because the maltene fraction represents the portion of the asphalt that chemically reacts with the polymer modifier. The rheological behavior of the blends was determined from oscillatory shear flow data. Analysis of the G′, G′′, G* moduli and phase angle (δ) as a function of oscillatory frequency for various temperatures led to the conclusion that the maltenes behaved as a pseudo-homogeneous viscoelastic material that could dissipate stress without presenting structural changes. Furthermore, all maltenes–polymer blends behaved more viscoelastically than the non-blended maltenes depending on the amount of the polymer contained in the formulation. The blend viscosity increased with polymer concentration, and this increase was seen in both the viscous and elastic moduli. Furthermore, performance grade trials were also performed according to the AASHTO TP5 to determine the failing temperature. It was noticed that the limiting temperature increased with the modifier concentration with a δ between 50° and 60°, indirect value of elasticity found to have industrial applications for asphalt pavements.     

Development of polycarbonate/acrylonitrile–butadiene–styrene copolymer based composites with functional fillers for car audio chassis

Environmental regulations require the improvement of automobile fuel efficiency. This can be achieved mainly by reducing the weight of automobile components. In this study, polycarbonate/acrylonitrile–butadiene–styrene copolymer (PC/ABS) based composite mixed with glass fibers and metal fibers was developed and its suitability of application into car audio chassis was investigated. The test materials were prepared with various contents of metal fibers because of the fibers’ excellent mechanical and electrical properties. In this study, the morphologies of the materials were investigated to confirm the dispersion of the fillers and the interfacial characteristics between the fillers and the base material. In addition, the mechanical and electrical characteristics of the PC/ABS based composites, which depended on the metal fiber content, were evaluated using key mechanical (impact, tensile and flexural) and electrical tests such as electromagnetic interference (EMI) and surface resistance. The proper proportion of the metal fibers in PC/ABS based composites was determined from the test results. Finally, the applicability of PC/ABS based composites in car audio chassis was evaluated through weight reduction analysis and cost-benefit analysis.     

Hopping conduction on carbon black/styrene–butadiene–styrene composites

This study describes the preparation and electrical characterisation of conducting carbon black-filled/styrene–butadiene–styrene tri-block copolymer. Composites containing 5 and 10 vol% of carbon black were studied. The carbon black distribution, conductive mechanism and electrical properties of the composites were investigated from 8 to 304 K. For the first time, an analysis of the differential activation energy is carried out for carbon black composites, allowing the classification of the variable range hopping as one-dimensional for composite containing 5% of carbon black and as three-dimensional for the composite containing 10% of carbon black. Such results are found to be determined by two factors: the concentration of carbon black in the filler-rich phase and by the structural continuity of this phase. Increasing the carbon black content induces structural transition that results in variable range hopping conduction changing from one-dimensional to three-dimensional. From the hopping parameters, the mean hopping distance, the density of active centres and the energy associated with it were obtained.     

Significant improvement in static and dynamic mechanical properties of graphene oxide–carbon nanotube acrylonitrile butadiene styrene hybrid composites

Herein, hybridization of graphene nanosheets and carbon nanotubes (CNTs) has been made to solve the problem of restacking of graphene nanosheets and agglomeration of CNTs. The multiwalled carbon nanotubes (MWCNTs), reduced graphene oxide (RGO) and graphene oxide–carbon nanotubes (GCNTs) reinforced acrylonitrile butadiene styrene (ABS) composites have been prepared using micro-twin-screw extruder. The effect of these reinforcements on static and dynamic mechanical properties of composites is studied. The ultimate tensile strength and elastic modulus for 7 wt.% GCNT–ABS composites show enhancement of 26.1 and 71.3% over pure ABS matrix, respectively. Various parameters such as coefficient “C” factor (the ratio of storage modulus of the composite to polymer in glassy and rubbery regions), degree of entanglement, crosslink density and adhesion factor have been calculated to analyze the interaction between fillers and polymer matrix. The 3-D hybrid structure of GCNTs overcomes the associated problem of CNTs agglomeration and graphene restacking. GCNT hybrid composites show higher dispersion as well as effectiveness for increased filler amount as compared to RGO and MWCNTs based composites. GCNTs prove its superiority over MWCNTs and RGO by showing a synergistic effect in the glass transition temperature and storage modulus. Raman spectroscopy and scanning electron microscopy are used to confirm the interaction and distribution of the filler and matrix, respectively.     

Pavement performance evaluation of recycled styrene–butadiene–styrene-modified asphalt mixture

More and more styrene–butadiene–styrene (SBS)-modified asphalt waste materials are being discarded with the increase in road service life. The recycling of these waste pavement materials can reduce environmental pollution and help save resources. However, the low-temperature performance and the fatigue resistance of recycled asphalt mixture are significantly affected by the addition of reclaimed asphalt pavement (RAP). In order to evaluate the low-temperature performance and the fatigue resistance of recycled SBS-modified asphalt mixture, three points bending test, Fénix test and Ensayo de BArrido de DEformaciones test were conducted. Additionally, the differences of recycling between SBS-modified RAP with different ageing conditions and ordinary unmodified RAP were compared. The results showed that fatigue resistance of modified recycling of asphalt mixture with different RAPs did not vary much under low temperature (?5 °C) while displaying an obvious difference under higher temperature. SBS-modified RAP under light ageing condition was suitable for modified recycling. However, the SBS-modified asphalt from RAP under serious ageing condition would lose modification effect resulting in a great reduction of the low-temperature crack resistance and the fatigue resistance. Therefore, it is necessary to evaluate the ageing degree of RAP before recycling SBS-modified asphalt mixture. The SBS-modified RAP under serious ageing condition (SM-RAP) is not recommended for directly modified recycling. But considering for further utilisation, the SM-RAP used for unmodified recycling as ordinary unmodified RAP can be regarded as a good choice and the RAP content should be restricted to less than 30%.     

Electrical,rheological and morphological studies in co-continuous blends of polyamide 6 and acrylonitrile–butadiene–styrene with multiwall carbon nanotubes prepared by melt blending

Multiwall carbon nanotubes (MWNT) were incorporated in melt-mixed co-continuous blends of polyamide 6 (PA6) and acrylonitrile–butadiene–styrene (ABS) using a conical twin-screw microcompounder. The state of dispersion of MWNT in the blends was assessed through AC electrical conductivity measurements and melt-rheological investigations. The electrical and rheological percolation threshold in PA6/ABS blends was ～3–4 and ～1–2 wt% MWNT, respectively. A unique reactive modifier (sodium salt of 6-amino hexanoic acid, Na–AHA) was employed to facilitate ‘network-like’ structure of MWNT and to confine them in a specific phase. This was achieved by establishing specific interactions with the delocalized ‘π-electron’ clouds of MWNT and melt-interfacial reaction during melt-mixing. The electrical percolation threshold was significantly reduced in the blends (～0.25 wt%) in the presence of Na–AHA modified MWNT and even coincided with the rheological percolation threshold. Significant refinement in the co-continuous structure was also observed in the presence of Na–AHA modified MWNT.     

The effects of electron beam irradiation on the thermal properties,fatigue life and natural weathering of styrene butadiene rubber/recycled acrylonitrile–butadiene rubber blends

The effects of electron beam (EB) irradiation on the thermal properties, fatigue life and natural weathering of styrene butadiene rubber/recycled acrylonitrile–butadiene rubber (SBR/NBRr) blends were investigated. The SBR/NBRr blends were prepared at 95/5, 85/15, 75/25, 65/35, or 50/50 blend ratios with and without the presence of a 3 part per hundred rubber (phr) of polyfunctional monomer, trimethylolpropane triacrylate (TMPTA). Results indicate that the crystallisation temperature (T_c) observed in polymeric blends is due to the alignment of polymer chains forming a semi-crystalline phase. Addition of TMPTA helps to align polymer chains through crosslinking. More crosslinking occurred between polymer blends with the help of TMPTA, upon irradiation. The improvement in fatigue life can also be associated with the stabilisation of SBR/NBRr blends upon irradiation and irradiation-induced crosslinking, which was accomplished with relatively low radiation-induced oxidative degradation in the presence of TMPTA. The tensile properties of both blends decreased over the periods of environmental exposure due to the effect of polymer degradation. After 6 months, the irradiated SBR/NBRr blends could not retain better retention [mainly with 25, 35 or 50 phr of recycled acrylonitrile–butadiene rubber (NBRr) particles] due to the samples becoming brittle over the long period of outdoor exposure.     

Filler dispersion evolution of acrylonitrile–butadiene rubber/graphite nanocomposites during processing

In this work, acrylonitrile–butadiene rubber/expanded graphite compounds with initial fine dispersion of nanosize graphite were prepared by latex compounding method, and then the dispersion evolution of the graphite during subsequent mixing and vulcanization was carefully investigated by using rubber process analysis, X-ray diffraction and transmission electron microscopy. The results showed that a significant filler network was already formed in the initial compounds because of the nanoscale dispersion and the high width/thickness ratio of graphite even at a content of less than 5 phr. During shearing, the graphite dispersion evolution is strongly related to the initial filler network. The filler network as well as the dispersion could also be obviously altered by changing the curing pressure and temperature during vulcanization, suggesting that the initial fine dispersion of graphite in the rubber/graphite nanocomposites could be maintained by reducing shear and by curing at a higher temperature and at a lower pressure.     

Mechanical, electrical and electro-mechanical properties of thermoplastic elastomer styrene–butadiene–styrene/multiwall carbon nanotubes composites

Composites of styrene–butadiene–styrene (SBS) block copolymer with multiwall carbon nanotubes were processed by solution casting to investigate the influence of filler content, the different ratios of styrene/butadiene in the copolymer and the architecture of the SBS matrix on the electrical, mechanical and electro-mechanical properties of the composites. It was found that filler content and elastomer matrix architecture influence the percolation threshold and consequently the overall composite electrical conductivity. The mechanical properties are mainly affected by the styrene and filler content. Hopping between nearest fillers is proposed as the main mechanism for the composite conduction. The variation of the electrical resistivity is linear with the deformation. This fact, together with the gauge factor values in the range of 2–18, results in appropriate composites to be used as (large) deformation sensors.     

Application of carboxylated styrene–butadiene emulsion-Portland cement mixture as road base material

This study investigated the effects of the addition of a carboxylated styrene–butadiene emulsion (CSBE) and Portland cement on the long-term performance of road base. The specimens stabilised with Portland cement (0–6%) and CSBE (5–10%) were subjected to different stress sequences in order to study the unconfined compressive strength, flexural strength (FS), soaked and unsoaked California bearing ratio, dynamic creep and wheel-tracking characteristics of seven-day-cured specimens. The FS tests showed that the addition of a 4% Portland cement–7% CSBE mixture resulted in improvements of 48.9% of modulus of rupture as compared to the sample with 4% cement. The permanent strain behaviour of the samples was assessed by the Zhou three-stage creep model. The results of dynamic creep and wheel-tracking tests showed that the permanent deformation characteristics were considerably improved by the addition of a 4% Portland cement–7% CSBE mixture, which resulted in reduction of permanent strain of the mixture. Therefore, this research presents a new polymer additive with outstanding engineering properties for use in road bases.     

Thermal resistance and dynamic damping properties of poly (styrene–butadiene–styrene)/thermoplastic polyurethane composites elastomer material

We present the preparation of novel thermoplastic composites elastomer material based on poly (styrene–butadiene–styrene) (SBS), ester-type polyurethane (TPU-EX) and ether-type polyurethane (TPU-ER) materials via melt blending. A series of studies were conducted on the relationship between their morphology, thermal resistance, mechanical properties, and dynamic damping properties, given different compositions. An important feature of the SBS/TPU composites elastomer materials of all compositions is their uniform transparency, because the particles are very small with a narrow size distribution and the refractive indices of SBS and TPU are coincide. Additionally, the thermal resistance, dynamic damping properties and mechanical properties of SBS before and after thermal aging are improved as the amount of added TPU is increased, suggesting that blending SBS with TPU is consistent with the compound rule. In addition, the SBS/TPU composites elastomer materials have better dynamic damping properties at high frequency.     

Reinforcement and antioxidation effects of antioxidant functionalized silica in styrene–butadiene rubber

In order to improve the dispersion of silica in rubber matrix and to avoid volatility and extractability of the antioxidants, antioxidant functionalized silica is synthesized through reaction of precipitated silica and antioxidant coupling agent which is synthesized by (3-glycidyloxypropyl)trimethoxysilane (A-187) and N-phenyl-1,4-phenylenediamine (PPDA). This antioxidant functionalized silica with different antioxidant content is then incorporated into styrene–butadiene rubber (SBR) to study their reinforcement and antioxidation effects. The tensile strength of these composites is much higher than that of neat silica/SBR, and increases with increasing antioxidant content. It is close to that of bis(triethoxysilylpropyl)tetrasulfane (TESPT) modified silica/SBR when the antioxidant content exceeds 3.9% (by weight to silica). Furthermore, SBR filled with antioxidant functionalized silica has greatly improved stability in thermal oxidative ageing and damp heat ageing.     

The microstructure and fracture performance of styrene–butadiene–methylmethacrylate block copolymer-modified epoxy polymers

The microstructure and fracture performance of an anhydride-cured epoxy polymer modified with two poly(styrene)-b-1,4-poly(butadiene)-b-poly(methyl methacrylate) (SBM) block copolymers were investigated in bulk form, and when used as the matrix material in carbon fibre reinforced composites. The ‘E21’ SBM block copolymer has a higher butadiene content and molecular weight than the ‘E41’. A network of aggregated spherical micelles was observed for the E21 SBM modified epoxy, which became increasingly interconnected as the SBM content was increased. A steady increase in the fracture energy was measured with increasing E21 content, from 96 to 511 J/m² for 15 wt% of E21. Well-dispersed ‘raspberry’-like SBM particles, with a sphere-on-sphere morphology of a poly(styrene) core covered with poly(butadiene) particles, in an epoxy matrix were obtained for loadings up to 7.5 wt% of E41 SBM. This changed to a partially phase-inverted structure at higher E41 contents, accompanied by a significant jump in the measured fracture energy to 1032 J/m² at 15 wt% of E41. The glass transition temperatures remained unchanged with the addition of SBM, indicating a complete phase separation. Electron microscopy and cross polarised transmission optical microscopy revealed localised shear band yielding, debonding and void growth as the main toughening mechanisms. Significant improvements in fracture energy were not observed in the fibre composites, indicating poor toughness transfer from the bulk to the composite. The fibre bridging observed for the unmodified epoxy matrix was reduced due to better fibre–matrix adhesion. The size of the crack tip deformation zone in the composites was restricted by the fibres, hence reducing the measured fracture energy compared to the bulk for the toughest matrix materials.