Showing papers on "Styrene-butadiene published in 2005"

Evaluation of Open-graded Friction Course Mixtures Containing Cellulose Fibers and Styrene Butadiene Rubber Polymer

Abstract: Open-graded friction course (OGFC) or porous mixtures consist of an open gradation, mostly of coarse size aggregate with little fines. The benefits of an OGFC mixture are typically increased surface permeability, noise reduction, and enhanced surface friction, especially in wet weather. This paper presents the results of a study investigating four different OGFC mixes containing no additives, cellulose fibers, styrene butadiene rubber (SBR) polymer, and a combination of both fibers and SBR polymer. Mix designs were performed according to the design procedure proposed by the National Center of Asphalt Technology for a range of 4.5–6.5% asphalt content. The mixture containing fibers and SBR polymer was selected as an acceptable mix design with an optimum asphalt content of 6.5%. The moisture susceptibility of the selected mix at optimum asphalt content was evaluated. Results were compared with that for a dense mix.

Study on flammability of montmorillonite/styrene‐butadiene rubber (SBR) nanocomposites

Abstract: The flammability of montmorillonite (MMT)/SBR nanocomposites, prepared by the technique of cocoagulating rubber latex and clay aqueous suspension, was investigated. Flammability studies, performed on the cone calorimeter, showed that the maximum heat release rate (HRR) of SBR decreased from 1987 to 1442 kw/m2 with the introduction of nanoclay (20 phr). This nanocomposite had the lowest mass loss rate and the largest amount of char upon combustion compared with conventional SBR composites with the same clay loading and pure SBR. The permeability properties of MMT/SBR composites were also measured. It was deduced that the lowered permeability was responsible for the reduced mass loss rate and hence the lower HRR. Unfortunately, the oxygen index (OI) of the nanocomposites was not as high as expected. Combination of Mg(OH)2 and clay was effective for the improvement of both mechanical properties and OI. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 844–849, 2005

Nanostructured Thermosetting Systems from Epoxidized Styrene Butadiene Block Copolymers

Abstract: Nanostructured thermosetting materials were prepared by modification of an epoxy resin with 30 wt.-% epoxidized polystyrene-block-polybutadiene copolymer (PS-b-PepB). The copolymer self-assembles into a well-defined hexagonal nanoordered structure, of around 30-nm diameter, thus establishing its use as structure-directing agent to generate nanostructured thermosetting materials. The study confirms pathways towards tailoring interactions betwwen thermosetting matrices and immiscible block copolymers by using the concept of unctionalization to build nanostructured polymer matrices.

Physicomechanical properties of α‐cellulose–filled styrene–butadiene rubber composites

Abstract: In this research, the influence of adding -cellulose powder to styrene- butadiene rubber (SBR) com- pounds was investigated. Physicomechanical properties of SBR--cellulose composites, including tensile strength, elongation, Young's modulus, tear strength, hardness, abra- sion, resilience, and compression set, before and after age- ing, were determined and analyzed. Young's modulus, hardness, and compression set increased and elongation and resilience decreased with increasing -cellulose loading in the composites, whereas tensile strength, tear strength, and abrasion resistance initially increased at low -cellulose con- centration (5 phr), after which these properties decreased with increasing -cellulose content. Lower loadings of -cel- lulose (5 phr) showed better results than higher loadings, given that tensile strength, tear strength, and abrasion resis- tance increased at low -cellulose concentration. Theoretical prediction of elastic modulus was carried out using rule of mixtures, Hashin, Kerner, and Halpin-Tsai equations. Cal- culated results show that these equations are not suitable for accurate prediction for the work carried out. However, these models can be used with confidence for the prediction of elastic modulus because experimental results are higher than the calculated values. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2203-2211, 2005

Mechanical and flame‐retarding properties of styrene–butadiene rubber filled with nano‐CaCO3 as a filler and linseed oil as an extender

Abstract: A nanosize CaCO3 filler was synthesized by an in situ deposition technique, and its size was confirmed by X-ray diffraction CaCO3 was prepared in three different sizes (21, 15, and 9 nm) Styrene–butadiene rubber (SBR) was filled with 2–10 wt % nano-CaCO3 with 2% linseed oil as an extender Nano-CaCO3–SBR rubber composites were compounded on a two-roll mill and molded on a compression-molding machine Properties such as the specific gravity, swelling index, hardness, tensile strength, abrasion resistance, modulus at 300% elongation, flame retardancy, and elongation at break were measured Because of the reduction in the nanosize of CaCO3, drastic improvements in the mechanical properties were found The size of 9 nm showed the highest increase in the tensile strength (389 MPa) in comparison with commercial CaCO3 and the two other sizes of nano-CaCO3 up to an 8 wt % loading in SBR The elongation at break also increased up to 824% for the 9-nm size in comparison with commercial CaCO3 and the two other sizes of nano-CaCO3 Also, these results were compared with nano-CaCO3-filled SBR without linseed oil as an extender The modulus at 300% elongation, hardness, specific gravity, and flame-retarding properties increased with a reduction in the nanosize with linseed oil as an extender, which helped with the uniform dispersion of nano-CaCO3 in the rubber matrix © 2005 Wiley Periodicals, Inc J Appl Polym Sci 98: 2563–2571, 2005

Effect of carbon black on properties of rubber nanocomposites

Abstract: Polymer based nanocomposites were prepared using brominated poly(isobutylene-co-paramethylstyrene) (BIMS) rubber and octadecyl amine modified montmorillonite nanoclay. The effect of nature and loading of carbon black on these nanocomposites and the control BIMS was investigated thoroughly using X-ray diffraction technique (XRD), Fourier transform infrared spectroscopy (FTIR), and mechanical properties. The addition of 4 parts of the modified nanoclay to 20 phr N550 carbon black filled samples increased the tensile strength by 53%. Out of the three different grades of carbon black (N330, N550, and N660), N550 showed the best effect of nanoclay. Optimum results were obtained with the 20 phr filler loading. For comparison, china clay and silica at the same loading were used. Fifty-six and 46% improvements in tensile strength were achieved with 4 parts of nanoclay added to the silica and the china clay filled samples, respectively. N330 carbon black (20 parts) filled styrene butadiene rubber (SBR) based nanocomposite registered 20% higher tensile strength with 4 parts of the modified nanoclay. In all the above carbon black filled nanocomposites, the modulus was improved in the range of 30 to 125%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 443–451, 2005

Sulfur-free lignin as reinforcing component of styrene–butadiene rubber

Abstract: The potential application of lignin biopolymer as a component of styrene–butadiene rubber was examined with regard to its ability to reinforce the vulcanizates. It was shown that the sulfur-free lignin preparation improved physicomechanical properties of rubber. The determination of the coefficient of lignin activity confirmed that lignin acts as an active filler. FTIR characteristics of lignin isolated from the vulcanizate containing 20 phr lignin indicated its interaction with the sulfur system, resulting in formation of noncyclic sulfide structures. In the case of higher lignin amount in the vulcanizate, some interfacial interaction between lignin and SBR may occur. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 924–929, 2005

Phase change material (pcm) compositions for thermal management

Abstract: The present invention relates to a Phase Change Material (PCM) composition comprising a) from 20 to 80 wt% of a PCM; and b) from 20 to 80 wt% of one or more polymers chosen from the group consisting of b1) Very Low Density Polyethylene (VLDPE) having a density equal or lower than 0.910 g/cm3 measured according to ASTM 792; b2) Ethylene Propylene Rubber (EPR) having a density equal or lower than 0.900 g/cm3 measured according to ASTM 792; b3) Styrene Ethylene Butadiene Styrene (SEBS) copolymers; and b4) Styrene Butadiene Styrene (SBS) copolymers. The PCM composition of the present invention can be used in applications where thermal management is needed, like for example in building, automotive, packaging, garments and footwear.

Unique rheological behavior of rubber based nanocomposites

Abstract: Montmorillonite clay (N) based nanocomposites were prepared using three different grades of acrylonitrile butadiene rubber (NBR) (19%, 34%, and 50% acrylonitrile contents), styrene butadiene rubber (SBR), and polybutadiene rubber (BR). Rheological study was carried out on these nanocomposites at three different temperatures (110 °C, 120 °C, and 130 °C) over a range of shear rates for comparison. The results showed that the shear viscosity decreased with increasing shear rate and incorporation of the unmodified (N) and the modified (OC) fillers up to a certain loading, when the results were compared with the gum rubber. This effect became more prominent with increasing polarity of the rubber. The die swell, on the other hand, decreased with loading of N and OC. With increasing filler volume fraction, the die swell further decreased. Decrease of viscosity with concomitant decrease of die swell is unique in such systems. Consecutive runs of the same sample over different shear rates increased the viscosity. The results were explained with the help of X-Ray Diffraction (XRD) data and Transmission Electron Microscopy (TEM).

Spectral and thermal characterization of styrene- butadiene copolymers with different architectures

Abstract: Three types of styrene-butadiene copolymers ? two block copolymers (poly(styrene-b-butadiene-b-styrene) linear triblock copolymer, poly(butadiene-b-styrene)4 star block copolymer) and a poly(butadiene-co-styrene) random copolymer have been investigated by Fourier transform infrared (FT-IR) spectrometry, nuclear magnetic resonance ( 1 3 C NMR) spectrometry, dynamical mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC) in order to find correlations between their macromolecular structures and physical properties. The main spectral (PT-IR and 1 3 C NMR features which discriminate between block and random copolymers have been established. A band at 1702 cm - 1 was found to be typical for the random copolymer, while the extinction coefficients of some bands (699 cm - 1 (PS), 966 cm - 1 (trans PB), 2848 cm - 1 (PB) and 2920 cm - 1 (PB) cm - 1 ) are different for star copolymer in comparison with the corresponding linear block copolymer. The relations for composition determination from 1 3 C NMR data for each type of copolymer were established. DSC and DMTA analyses were used to compare the degrees of mixing at the interface in the block copolymers and to examinate the supermolecular structure of the block copolymers. The domain disruption temperature (T D D ) has been detected.

Studies on the cure and mechanical properties of blends of natural rubber with dichlorocarbene modified styrene–butadiene rubber and chloroprene rubber

Abstract: This paper focused on the comparative evaluation of cure characteristics and mechanical properties of blends of natural rubber with dichlorocarbene modified styrene–butadiene rubber and chloroprene rubber with different blend composition. It was found that the Mooney scorch time and cure index shows a negative deviation from the calculated value based on the interpolation between the two component elastomers. However for the blends, modulus and hardness show a positive deviation. The mechanical properties of NR/DCSBR blend are higher than that of NR/CR blends. Flammability, oil and ozone resistance of the blend showed that as the NR content in the blend increases these properties were decreases and also NR/DCSBR blend showed excellent thermal, oil and ozone resistance than that of NR/CR in entire blend ratios. The mechanical properties, modulus and hardness were also investigated after oil immersion. The changes in mechanical properties were correlated with variation in cross-link density estimated from stress–strain and swelling behavior.

Morphology study of rubber based nanocomposites by transmission electron microscopy and atomic force microscopy

Abstract: Rubber based nanocomposites were prepared using octadecyl amine modified Na-montmorillonite clay (OC) and Styrene Butadiene Rubber (SBR) having styrene content of 15, 23 and 40% respectively and Acrylonitrile Butadiene Rubber (NBR) having acrylonitrile content of 19, 34 and 50% respectively. The morphology of the nanocomposites was investigated using Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM) and X-ray Diffraction Technique (XRD). The TEM photographs of the unmodified clay loaded SBR nanocomposite showed agglomeration, while the modified clay loaded SBRs of all the grades revealed complete exfoliation. The NBRs, on the other hand, gave unexfoliated and intercalated clay structures both with the unmodified and the modified clays, except in the case of NBR having 19% of acrylonitrile and 4% of the unmodified clay. The AFM data were in good accord with the TEM results. The particle dimensions were within the range of 10–20 nm in the case of SBR sample having 4 parts of the modified clay. NBRs having 34 and 50% acrylonitrile contents and 4 parts of OC showed clay particles ranging from 50–70 nm and 70–100 nm respectively. On comparison of the rubbers having different nature and contents of functional groups and filler loadings, significant effect on the morphology of the composite was observed. The nature of solvent used to prepare the nanocomposites also affected the morphology. XRD data further corroborated the facts in all the above cases.

Preparation, structure, and properties of a novel rectorite/styrene-butadiene copolymer nanocomposite

Abstract: Rectorite/styrene–butadiene copolymer (SBR) nanocomposite was prepared by cocoagulating SBR latex and rectorite/water suspension. Transmission electron microscopy showed that the layers of rectorite were well dispersed in the SBR matrix and the aspect ratio (width/thickness) of it was higher than that of montmorillonite (MMT). X-ray diffraction indicated that the nanocomposite produced by this method was of neither intercalated type nor exfoliated type. The gas barrier properties and mechanical properties of the novel nanocomposites were excellent. The nanocomposites are expected to be candidates for tire tube or inner materials. Rectorite appears to be a promising filler for the nanocomposite. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 324–328, 2005

Effect of organic fibers on open-graded friction course mixture properties

Abstract: Open-graded friction course (OGFC) or porous asphalt mixtures are special mixes used for improving the surface friction, increasing surface permeability, and reducing pavement noise. The mix consists mostly of coarse size aggregate with little fines. This study was conducted to evaluate the effect of two types of organic fibers: date-palm fibers and textile fibers, in combination with styrene butadiene rubber (SBR) polymer on the properties of OGFC mixes. A total of six different mixes were evaluated. Mix designs were performed according to the design procedure proposed by the National Center of Asphalt Technology (NCAT) for a range of 4.5–6.5% asphalt content. One-way ANOVA using the Tukey method of multiple comparisons was used to test the effect of the modifier and/or stabilizer on abrasion as an indication of raveling potential as well as draindown. The results indicated that the asphalt mix containing date-palm fibers and SBR polymer at 5.0% and the asphalt mix containing textile fibers and SBR polym...

Effect of nanoclay on the dynamic mechanical properties of styrene butadiene and acrylonitrile butadiene rubber vulcanizates

Abstract: Nanocomposites based on Styrene Butadiene Rubber (SBR) and Acrylonitrile Butadiene Rubber (NBR) with varying acrylonitrile contents (19%, 34% and 50%, respectively) and octadecyl amine modified and unmodified Na-Montmorillonite clays were prepared. Dynamic mechanical thermal analysis (DMTA) was performed on these composites over a range of temperatures (−80 °C to +80 °C), frequencies (0.032 Hz to 32 Hz) and strains (0.001% to 10%). The results showed that there were significant changes in tan delta peak temperature and height and storage modulus with the addition of small amount (4 phr) of the modified and the unmodified fillers. These were magnified with the increase of filler loading. The tan delta peak heights decreased and the storage modulus increased in general. With increasing strain, the nanocomposites showed lowering of storage modulus, because of the breakdown of the agglomerated structures. The torage modulus increased with increasing frequency, and the modified filler loaded samples r...

The effects of filler content on cure and mechanical properties of dichlorocarbene modified styrene butadiene rubber/carbon black composites

Abstract: A study has been carried out on the curing characteristics and mechanical properties of carbon black filled dichlorocarbene modified styrene butadiene rubber (DCSBR). Processing characteristics such as optimum cure time and maximum torque increases with increasing of the concentration of carbon black in DCSBR whereas scorch time decreases. The mechanical properties and resistance of the vulcanizate towards thermal, flame and oil resistance have been carried out. Variation of bound rubber content of carbon black filled DCSBR and the influence of the extracting temperature on the bound rubber content was investigated and its activation energy was calculated from the Arrhenius plot. The reinforcing nature of the filler was assessed from stress strain and swelling data. The enhancement in mechanical properties was supported by data on the increased content of crosslink density in these samples obtained from swelling and stress strain analysis. The results of the studies indicate that carbon black can be used as a good reinforcing filler for DCSBR.

Comparison of nano CaCO 3 and flyash filled with styrene butadiene rubber on mechanical and thermal properties

Abstract: Different particle sizes (21, 15, 9 nm) of CaCO 3 were synthesized by in-situ deposition technique and confirmed by X-ray diffraction method. The nano CaCO 3 was added from 0.1 wt % to 0.5 wt % in the styrene butadiene rubber (SBR). Rubber nanocomposties were compounded on two-roll mill and molded in compression molding machine. Mechanical properties such as tensile strength, elongation at break, modulus at 300 % elongation, hardness, specific gravity, swelling index, flame retardency and abrasion resistance were studied. These results were compared with flyash filled SBR. There was an improvement in properties of rubber nanocomposites because of uniform dispersion of nano CaCO 3 particles in the matrix that intercalates the rubber chains. Hence degree of crosslinking increases multifold in comparison to commercial CaCO a and flyash.