Butadiene Styrene Polymer Research Articles

Characterization of emissions from a desktop 3D printer and indoor air measurements in office settings

ABSTRACTEmissions from a desktop 3D printer based on fused deposition modeling (FDM) technology were measured in a test chamber and indoor air was monitored in office settings. Ultrafine aerosol (UFA) emissions were higher while printing a standard object with polylactic acid (PLA) than with acrylonitrile butadiene styrene (ABS) polymer (2.1 × 109 vs. 2.4 × 108 particles/min). Prolonged use of the printer led to higher emission rates (factor 2 with PLA and 4 with ABS, measured after seven months of occasional use).UFA consisted mainly of volatile droplets, and some small (100–300 nm diameter) iron containing and soot-like particles were found. Emissions of inhalable and respirable dust were below the limit of detection (LOD) when measured gravimetrically, and only slightly higher than background when measured with an aerosol spectrometer. Emissions of volatile organic compounds (VOC) were in the range of 10 µg/min. Styrene accounted for more than 50% of total VOC emitted when printing with ABS; for PLA, methyl methacrylate (MMA, 37% of TVOC) was detected as the predominant compound. Two polycyclic aromatic hydrocarbons (PAH), fluoranthene and pyrene, were observed in very low amounts. All other analyzed PAH, as well as inorganic gases and metal emissions except iron (Fe) and zinc (Zn), were below the LOD or did not differ from background without printing.A single 3D print (165 min) in a large, well-ventilated office did not significantly increase the UFA and VOC concentrations, whereas these were readily detectable in a small, unventilated room, with UFA concentrations increasing by 2,000 particles/cm3 and MMA reaching a peak of 21 µg/m3 and still being detectable in the room even 20 hr after printing.

Effects of silanization temperature and silica type on properties of silica‐filled solution styrene butadiene rubber (SSBR) for passenger car tire tread compounds

ABSTRACTInfluence of silanization temperature on properties of silica‐filled solution polymerized styrene butadiene rubber was investigated. Two types of silica, i.e., highly dispersible silica (HDSi) and conventional silica (CSi), were compared. Results show that the increased silanization temperature leads to the enhanced rubber–filler interaction, filler dispersion, and cross‐link density giving rise to the improvement in vulcanizate properties such as modulus, heat build‐up (HBU), and dynamic set, as well as tire performance, e.g., wet grip (WG), rolling resistance (RR), and abrasion resistance. Great care, however, must be taken to avoid the scorching phenomenon during the mixing process at too high temperature. Taken as a whole, the balanced properties are found at the silanization temperature of 140°C. Surprisingly, HDSi provides insignificant differences in degree of filler dispersion, WG, and RR, compared to CSi, despite its claimed greater dispersability. Probably, the relatively long mixing time used in this experiment may override the influence of silica type. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43342.

Full 3-D Printed Microwave Termination: A Simple and Low-Cost Solution

This paper describes the realization and characterization of microwave 3-D printed loads in rectangular waveguide technology. Several commercial materials were characterized at X-band (8–12 GHz). Their dielectric properties were extracted through the use of a cavity-perturbation method and a transmission/reflection rectangular waveguide method. A lossy carbon-loaded Acrylonitrile Butadiene Styrene (ABS) polymer was selected to realize a matched load between 8 and 12 GHz. Two different types of terminations were realized by fused deposition modeling: a hybrid 3-D printed termination (metallic waveguide + pyramidal polymer absorber + metallic short circuit) and a full 3-D printed termination (self-consistent matched load). Voltage standing wave ratio of less than 1.075 and 1.025 were measured over X-band for the hybrid and full 3-D printed terminations, respectively. Power behavior of the full 3-D printed termination was investigated. A very linear evolution of reflected power as a function of incident power amplitude was observed at 10 GHz up to 11.5 W. These 3-D printed devices appear as a very low cost solution for the realization of microwave matched loads in rectangular waveguide technology.

Assessing the challenges and issues in entry-level additive manufacturing machine

Entry-Level Additive Manufacturing (ELAM) machines are made far less sophisticated compared to premium Additive Manufacturing (AM) machines for the sake of affordability. Often, machine resolution is also compromised, which may raise a question mark on quality. It is essential to gain a working knowledge of quality issues, considering the present rate of penetration of 3D printers in manufacturing. The objective of this paper is to examine geometric limitations and challenges of entry-level AM machines when fabricating complex objects. A systemic literature review providing an overview of additive manufacturing technology, the definition of ELAM, followed by a discussion on challenges in ELAM and improvement in dimensional accuracy to help the end users understand their machine well are presented in the paper. Ten experiments were performed on ELAM using acrylonitrile butadiene styrene polymer to illustrate and classify the developed defects. Most of the parts produced from ELAM machine suffer from quality issues such as geometrical and dimensional inaccuracy, warpage, oozing and surface imperfection, nesting, non-formation and deposition. This investigation displays a more realistic picture of ELAMs by identifying important restrictions and limitations which otherwise are hardly available to the end users or the manufacturers. The findings will help ELAM manufacturers to innovate their machine and make it better for professional use.

Improvement of mechanical performance of solution styrene butadiene rubber by controlling the concentration and the size of in situ derived sol–gel silica particles

The silica particles generated from alkoxide route are grown onto the styrene butadiene polymer chains and offer a direct rubber to filler interaction. As a result, superior mechanical performance of the elastomeric composites can be realised.

Preparation and performance of silica/SBR masterbatches with high silica loading by latex compounding method

With the help of a new coupling agent Si747, silica water slurry and styrene–butadiene rubber (SBR) latex were successfully co-coagulated by the latex compounding method, even silica/SBR masterbatches with silica loading as high as 200 phr could be prepared by such method. Compared to the traditional dry blending method, the latex compounding method had lower energy consumption during mixing and better silica dispersion in rubber matrix. Meanwhile, the effect of the amount of silica in the SBR latex on the properties of silica/SBR composites was investigated, and the results showed that the larger the amount of silica in the rubber matrix, the stronger the filler network. The performance of these composites was good and the dispersion of silica was relatively homogeneous. Furthermore, the masterbatches with high silica loading were mixed with emulsion polymerized styrene–butadiene rubber (ESBR) or solution polymerized styrene–butadiene rubber (SSBR). The silica dispersed better in ESBR than in SSBR.

Rheological properties of road bitumen binders modified with SBS polymer and polyphosphoric acid

A commonly used method to improve the viscoelastic properties of road bitumens is polymer modification with styrene-butadiene-styrene (SBS). New binder modifiers are being searched for to provide a technically and economically justified alternative. A recent method of modification, which has been in use for over 15 years (mainly in the U.S.), is based on addition of polyphosphoric acid (PPA). The effect of modification with polyphosphoric acid is similar to that of oxidation, i.e. it increases the binder stiffness yet without compromising its low-temperature performance. The effect of modification with polyphosphoric acid has not been so far comprehensively tested in Poland. According to various reports from research projects carried out in different countries improvement of binder properties and durability of asphalt mixtures largely depends on the type of pure bitumen used. This paper describes the effect of PPA modifier on the rheological properties of a bitumen obtained from a Polish refinery.

Characterization of Adhesion and Healing at the Interface between Asphalt Binders and Aggregate Using Atomic Force Microscopy

The adhesion damage and healing in asphalt mixture have been studied at the macroscale for decades. This study investigated the adhesive performance and adhesion-healing property of asphalt binder–aggregate interface at the microscale. The study employed atomic force microscopy (AFM) to measure the adhesion force between asphalt binder [one base asphalt and one styrene–butadiene–styrene (SBS) modified asphalt] and silicon nitrite tip. In addition, two probes were selected for the AFM test, and the influences of the probe parameters on the test results were analyzed. On the basis of measurement of the adhesion forces, adhesion work was calculated, and the adhesive performance and adhesion-healing ability of the two asphalt binders were studied. The results showed that a relatively soft probe was suitable for measurement. With a combination of surface free energy data and AFM test results, SBS modified asphalt was found to have better adhesive performance and adhesion-healing ability. Also, the addition of SBS polymer induced an obvious contrast in phase separation behavior, which was responsible for the change in adhesion forces. This study provided fundamental research in the investigation of asphalt binder–aggregate interface and useful guidance for probe selection in the AFM test.

The use of fractional calculus to model the experimental creep-recovery behavior of modified bituminous binders

Fitting of experimental creep-recovery curves obtained from rheological tests carried out on viscoelastic materials can reveal difficulties when handled by classical rheological theories, which generally provide exponential-type functions requiring a great number of parameters to be determined. Fractional calculus may represent a natural framework to develop more synthetic and efficient methods, overcoming most of the problems encountered with the classical approach. In this paper, a fractional model consisting of a dashpot in series with a springpot is proposed to describe the viscoelastic behavior of modified bituminous binders used in road pavements. The purpose is twofold: (i) to evaluate the adequacy of a rheological model involving a limited number of parameters, each of which with a precise physical meaning; (ii) to improve the accuracy of other fractional approaches proposed in literature. The investigation was validated by means of experimental data gathered from shear creep-recovery tests carried out at various temperatures on two modified bituminous binders containing a styrene–butadiene–styrene polymer and crumb rubber from end-of-life tires.

Influence of network structure on the viscoelastic properties of dynamically vulcanized rubber/plastic blends: An alternative approach to understand the microstructure evolution

The formation of finely dispersed micron-sized cross-linked rubber agglomerates in the thermoplastic matrix during dynamic vulcanization is now a well accepted theory to explicate the final properties of thermoplastic vulcanizates (TPVs). Based on our previous results, we have investigated further in the present work on the most influential and essential parameters which controls the ultimate properties of the TPVs. Three TPVs based on poly[styrene-b-(ethylene-co-butylene)-b-styrene] triblock copolymer (S-EB-S) and solution polymerized styrene butadiene rubber (S-SBR) have been prepared containing different proportions of rubber fraction. A semi-efficient (SEV) sulphur based curing system has been adopted to cross-link the rubber phase and advanced microscopic techniques viz. transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) have been used for the microstructure analysis. Thereafter, dynamic experiments have been performed to correlate the morphological observations with viscoelastic properties. The experimental results and the morphological images confirm that the network structure formation during dynamic vulcanization and its integrity is the most influential parameter to cause the utmost properties of the TPVs. The finely dispersed cross-linked rubber particles obtained during dynamic vulcanization are actually the disintegrated and agglomerated rubber nano-particles having average particle size between 80 and 85nm. It has also been confirmed that the integrated rubber network structure has an inverse relationship with the proportion of rubber fraction present in the TPVs. Mechanical properties, melt rheology and dynamic viscoelastic measurements also support the network structure disruption and disintegration observed in the morphological images and thus, nullifies the supremacy of dispersed phase morphology theory behind the superior properties obtained from the TPVs. This work elucidates the necessity and importance of integrated network structure formation over the morphology evolution during dynamic vulcanization and leads to a new avenue to understand morphology–mechanical–rheological–viscoelastic property correlation in TPVs.

Dynamic mechanical relaxation of cross-linked styrene-butadiene polymers containing free chains: Possibility of reptation

The structure of styrene-butadiene rubbers (SBRs) consists of chains attached to cross-links of relatively small number density. These rubbers show an α-relaxation process that is attributed to segmental motions of the attached chains. To investigate how an SBR's rubber-like behavior would change when free chains interpenetrate its structure, we prepared one SBR of mol wt 120 × 103 containing 3–4% free chains of identical mol wt, and studied its dynamic mechanical relaxation. For 0.1 Hz frequency measurements, the α-relaxation peak appeared at 210 K, and a second relaxation peak, which we refer to as αR-relaxation, at 300 K. A third relaxation of small magnitude was resolved at temperatures between the αR- and the α-relaxation peaks, and its origin was discussed in relation to other studies. Spectral features of the αR-and the α-relaxations were found similar. We investigated the merits of the time-temperature superposition of the α- and of the αR-relaxations. The αR relaxation vanished when the free chains were extracted from the SBR by swelling-extraction procedure. The features of α-relaxation can be interpreted as segmental motions of the SBR, but the features of the αR-relaxation is be interpretable only in terms of tube model for diffusion of free chains in a lightly cross-linked structure. We estimated the mol wt of these free chains and the mass between entanglements, and then used these quantities to calculate, by using the Doi-Edwards formalism, the relaxation time of the αR-process at 293 K. This relaxation time agrees with the experimental value. The αR-relaxation seems consistent with the tube model for diffusion of free chains in the cross-linked structure of SBR.

Meticulous analysis and consequences of microstructure changes on melt rheology and dynamic viscoelasticity of thermoplastic vulcanizates upon reprocessing

ABSTRACTThermoplastic vulcanizates (TPVs), which are a special class of elastomer alloy, prepared by dynamic vulcanization possess unique morphology of finely dispersed micron‐size cross‐linked elastomeric particles in a continuous thermoplastic matrix. The present study investigates the microstructure formation of elastomeric phase and its associated morphological changes during reprocessing of TPVs based on poly[styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] triblock co‐polymer (S‐EB‐S) and solution polymerized styrene butadiene elastomer (S‐SBR) by scanning electron microscopy and atomic force microscopy. Semi‐efficient and efficient sulfur‐based curing systems have been adopted to cure the elastomeric phase and a comparative study has been made to demonstrate and explain the effect of reprocessing on the melt rheology and dynamic viscoelasticity of the TPVs. The present work also provides a better insight and guidance to control the microstructure of the cross‐linked elastomeric phase to prepare selectively co‐continuous or dispersed phase morphology. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41182.

Design and Analysis of Automotive Instrument Panel

This study presents the automotive instrument panel (IP) design in order to improve the quality, cost, and safety of the existing design. A few conceptual designs were generated based on safety aspect and ergonomic design. The most suitable design was selected using concepts scoring. The IP head impact simulation was conducted using finite element analysis (FEA) to predict the head injury criterion (HIC) value of the front passenger in vehicle according to ECE-R21 regulation. The finite element (FE) model, which consist of upper IP, lower IP, carrier structure and head-form, was built-up to carry out head impact analysis of the IP assembly. The optimum IP design was proposed by analysis of different materials, which are 20% talc filled rubber modified polypropylene (PP+EPDM-TD20), acrylonitrile butadiene styrene (ABS) polymer, and polypropylene (PP) copolymer. The HIC value for all IP was compared using simulation result and theoretical calculation. The lowest HIC value will reduce the head occupant injury. In this study, only the raw material cost was considered in cost evaluation. The IP from ABS polymer performed the lowest HIC value, which were 179.7 but very costly compare to other materials.

Influence of SBS and asphalt on SBS dispersion and the performance of modified asphalt

Styrene–butadiene–styrene (SBS) modified asphalt (PMA) was prepared by high shear method. Four asphalts with different components and four types of SBS copolymers with different S/B ratio and types were selected in this study. The influences of the asphalt components and SBS structure as well as SBS contents on the particle size distribution of SBS and properties of the SBS modified asphalt were investigated. Fluorescence microscope and the Image-Pro Plus program were chosen to characterize the microstructure and count the particle size distribution of SBS. The results show that the asphalt components, SBS structure and content had significant impacts on the particle size distribution of SBS polymer in asphalt and the performance of SBS modified asphalt. The high aromatics content and the low asphaltenes content could improve the dispersion of SBS in asphalt. When the S/B ratio is 30/70, the particle size distribution curve was the narrowest and the performance of modified asphalt was improved. With the content of SBS increasing, the particle size distribution curve became wide and the softening point of the modified asphalt was increased, while the penetration and the ductility were decreased. The viscosity at 135°C of modified asphalt was increased with the range of the particle size distribution curves becoming narrow.

Surface Treatment of Plastics with Ionic Liquids for Decorative Metal Deposition

Surface treatment of plastics for decorative metal plating has been developed for more than 20 years and is widespread applied in automotive, electronics and faucets industries. Main advantages in contrast to the use of bulk metals are savings of weight and costs, facilitating complex geometries and superior aesthetic appearance. Most applied plastics represent acrylonitrile butadiene styrene polymers (ABS), ABS polycarbonate blends and polyamide. Etching of the plastic surface is required to enable the electroless plating of metals like nickel or copper. State of the Art for surface activation is etching with hexavalent chromic sulfuric acid. It is cost efficient, robust and reliable.[1] Generally known, hexavalent chromium causes high environmental, health and safety impact. Moreover, the scope of application to different plastics is quite limited. Therefore, a sustainable and environmental-benign replacement of this substance of very high concern is demanded in the near future. Some concepts for the replacement of chromic acid are currently under investigation. The most public approaches are the use of potassium permanganate[2] or ozone[3]. Disadvantageously, these concepts improve health, safety and environmental impact only marginally. Moreover, complex waste handling and process equipment limit the potential as suitable substitute.We report a potential and metal-free replacement approach based on surface treatment with ionic liquids. Employed ionic liquids and additives bear substantial environmental, safety and health advantages. Beyond, they show high potential for broadening the scope of applied plastics.[4]

Resonance tracking atomic force acoustic microscopy quantitative modulus mapping of carbon nanotubes‐reinforced acrylonitrile–butadiene–styrene polymer

ABSTRACTThis work presents a resonance tracking atomic force acoustic microscopy (RT‐AFAM) quantitative modulus mapping of carbon nanotubes‐reinforced acrylonitrile–butadiene–styrene polymer. RT‐AFAM average local modulus values registered were in good agreement with those measured by nanoindentation test. RT‐AFAM mapping modulus, nanoindentation, and transmission electron microscopy imaging showed that carbon nanotubes reinforcement of acrylonitrile–butadiene–styrene polymer matrix gives an elastic modulus enhancement of approximately 18.3% compared with the polymer matrix alone and showed that this technique provides high spatial resolution and helps to characterize the elastic properties of reinforced thermoplastic polymers and new compound materials at nanoscale. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40628.

Nanoparticle and Gelation Stabilized Functional Composites of an Ionic Salt in a Hydrophobic Polymer Matrix

Polymer composites consisted of small hydrophilic pockets homogeneously dispersed in a hydrophobic polymer matrix are important in many applications where controlled release of the functional agent from the hydrophilic phase is needed. As an example, a release of biomolecules or drugs from therapeutic formulations or release of salt in anti-icing application can be mentioned. Here, we report a method for preparation of such a composite material consisted of small KCOOH salt pockets distributed in the styrene-butadiene-styrene (SBS) polymer matrix and demonstrate its effectiveness in anti-icing coatings. The mixtures of the aqueous KCOOH and SBS-cyclohexane solutions were firstly stabilized by adding silica nanoparticles to the emulsions and, even more, by gelation of the aqueous phase by agarose. The emulsions were observed in optical microscope to check its stability in time and characterized by rheological measurements. The dry composite materials were obtained via casting the emulsions onto the glass substrates and evaporations of the organic solvent. Composite polymer films were characterized by water contact angle (WCA) measurements. The release of KCOOH salt into water and the freezing delay experiments of water droplets on dry composite films demonstrated their anti-icing properties. It has been concluded that hydrophobic and thermoplastic SBS polymer allows incorporation of the hydrophilic pockets/phases through our technique that opens the possibility for controlled delivering of anti-icing agents from the composite.

Neural network modelling of asphalt adhesion determined by AFM

This study constructs a neural network (NN) model to quantify adhesion from atomic force microscopy (AFM) data. AFM data contain five-point force-distance values. A total of 760 observations are used to build NN model. To train the network, AFM tip-sample distance data, percentage of lime, type and percentage of polymer and asphalt chemical functional groups are given as inputs and AFM force as an output. To select the NN architecture, one and two hidden layers with varying neurons are tried with 10 input nodes in the input layer and 5 output nodes in the output layer. Two hidden layers with 9 and 17 nodes in the first and second layer, respectively, show the best performance. A 10-9-17-5 NN is selected as the final structure of the NN model. Test results for the trained model show good prediction ability. The model is further applied to evaluate the effect of five different percentages of lime on the adhesion of asphalt. Results show that increase in the percentage of lime is very effective at reducing moisture damage in a styrene butadiene polymer modified asphalt sample. However, increase in lime percentage above 1.5% does not help reduce moisture damage in the styrene butadiene styrene polymer modified sample.

Evaluation of the properties of bitumen modified by SBS copolymers with different styrene–butadiene structure

ABSTRACTFour styrene–butadiene–styrene(SBS) modified bitumens had been prepared by a base bitumen, a crosslinking agent and four SBS copolymers which differ in styrene blocks content and molecular configuration (radial or linear) under the same experimental conditions. Conventional properties, morphology, thermal behavior and microstructure were investigated by means of conventional tests, fluorescence microscopy, differential scanning calorimetry (DSC), and Fourier transform infrared (FT‐IR) spectroscopy. In terms of linear SBS polymers, the SBS molecule with the styrene content of 30% has a perfect dispersion and complete stretching in bitumen matrix, and in this case, the conventional properties and thermal stability of bitumen are enhanced substantially. However, the star SBS polymer due to long branched chains forming the preferable steric hindrance to enhance the intensity of base bitumen, plays a more important role in improving the conventional properties of base bitumen than linear SBS polymers. Furthermore, the FT‐IR spectra indicate that, the main bands assignations of four modified bitumens are identical and the significant variation is the peak intensity. And a noncomplete crosslinking reaction happens between the bitumen and each SBS polymer, which can efficiently prevent excessive cross‐linking from affecting the intrinsic bitumen characteristics. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40398.

Contribution of silica–rubber interactions on the viscoelastic behaviors of modified solution polymerized styrene butadiene rubbers (M-S-SBRs) filled with silica

Dynamic mechanical analysis of M-S-SBR filled with silica: the temperature dependence of loss factor, tan δ.