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Industrial Polymers
Published in Manas Chanda, Plastics Technology Handbook, 2017
Polybutadiene is made by solution polymerization of butadiene using Ziegler–Natta catalysts. Slight changes in catalyst composition produce drastic changes in the stereoregularity of the polymer. For example, polymers containing 97–98% of trans-1,4 structure can be produced by using Et3Al/VCl3 catalyst, those with 93–94% cis-1,4 structure by using Et2AlCl/CoCl2, and those with 90% 1,2-polybutadiene by using Et3/Al/Ti(OBu)4. The stereochemical composition of polybutadiene is important if the product is to be used as a base polymer for further grafting. For example, a polybutadiene with 60% trans-1,4, 20% cis-1,4, and 20% 1,2 configuration is used in the manufacture of ABS resin.
Ionic Chain-Reaction and Complex Coordination Polymerization (Addition Polymerization)
Published in Charles E. Carraher, Carraher's Polymer Chemistry, 2017
1,4-Butadiene can form three repeat units as described in (5.48): the 1,2; cis-1,4; and trans-1,4. Commercial polybutadiene is mainly composed of the cis-1,4 isomer and is known as butadiene rubber (BR) (Picture 5.9). In general, butadiene is polymerized using the stereoregulating catalysts. The composition of the resulting polybutadiene is quite dependent on the nature of the catalyst such that almost total trans-1,4 units, or cis-1,4 units, or 1,2 units can be formed as well as almost any combination of these units. The most important single application of polybutadiene polymers is its use in automotive tires where over 107 tons are used yearly in the U.S. manufacture of automobile tires. BR is usually blended with natural rubber (NR) or styrene–butadiene rubber (SBR) to improve the tire tread performance, particularly wear resistance.
Polymers
Published in Bryan Ellis, Ray Smith, Polymers, 2008
Miscellaneous: Rubber types used in HIPS/PPO blends include high cis and low cis polybutadiene, EPDM rubber and styrene- butadiene block copolymers. The most common type is high cis polybutadiene. Optimum impact props. occur with an average rubber particle size of approx. 2mm or less. A core-shell morphology and the addition of very small rubber particles (0.3mm) improve the props. Most of the HIPS that is used for PPO blends is designed specifically for this purpose [3]. Typical compositions for HIPS/PPO blends contain 40-85% (w/w) PPO [3,11]. The ratio of PPO to PS in blends may be determined from the intensity of the PPO peak at 854cm-1 and the PS peak at 700cm-1 in the IR spectrum [22]. Many grades of HIPS/PPO blends are available commercially. Some grades are designed for specific processing conditions such as foaming, profile extrusion and electroplating. Some speciality grades are designed for a single application e.g. electrical connectors (high heat grade) and exterior automotive parts (high-impact mineral-filled grade) [3]. Although HIPS/PPO blends may be prod. as sheet and for vacuum forming, the greatest volume use is in pellets for injection moulding
Styrene-butadiene branched star-shaped asphalt modifiers: Synthesis and mechanical characterization
Published in Chemical Engineering Communications, 2020
Sergio Alonso-Romero, Luis Medina-Torres, Roberto Zitzumbo, Diola Marina Nuñez-Ramirez
Characterization of the molecular weights of the linear polybutadiene, linear polystyrenes, and poly(styrene-butadiene) di-block polymers, as well as those of coupled copolymers samples, were obtained from a GPC analysis with tetrahydrofuran solutions (ca. 0.015 g/ml) and standards of polystyrene. Therefore, the molecular weight distribution, average molecular weights, and the weight numbers reported in this investigation are referred to polystyrene-comparable molecular weights; the Mw and Mn values for each sample were obtained using the equipment’s software. A liquid chromatograph, Model HP 1100, provided with a high-resolution 5 μm column of PL-gel for polymer analysis, was used. It was operated at 35 °C using THF as diluent (1 ml min−1). The concentration of the polymer solutions were 1 g L−1 and the injected volumes were 100 μL.
Integrated CNTs/SiO2 nano-additives on SBS polymeric superhydrophobic coatings for self-cleaning
Published in Surface Engineering, 2020
Bin Chen, Zaosheng Lv, Fen Guo, Yanfen Huang
Organic–inorganic hybrid method as an effective modification method, the incorporation of nano particles directly into polymers exhibits great potentials in fabricating superhydrophobic surfaces because of its low demand for equipment, simple operation, large-area fabrication and easy realization of industrialized production. Polymers, such as polyaniline [20], polyethersulfone [21], polypropylene [22], polydimethylsiloxane [23], polybenzoxazine [24], polystyrene [25], polycarbonate [26], and polytetrafluoroethylene [27], and nanoparticles, such as nanoparticles of SiO2 [28], TiO2 [29], ZnO [30] and carbon nanotubes (CNTs) [31], are widely used to fabricate superhydrophobic surfaces. Styrene–butadiene-styrene (SBS) triblock copolymers as a thermoplastic elastomer have two-phase morphology of spherical polystyrene block domains within matrix of polybutadiene. SBS are the world’s largest production and most similar to rubber performance, with low costs, and widely used in building [32,33]. As far as we know so far there are almost no reports on the use of SBS for the preparation of superhydrophobic coatings. Considering SBS possesses excellent tensile strength, good chemical resistance and outstanding low-temperature property, it is a kind of excellent polymers which can be applied to construct superhydrophobic coatings.
Viscoelastic transitions exhibited by modified and unmodified bitumen
Published in International Journal of Pavement Engineering, 2020
M. R. Nivitha, J. Murali Krishnan, K. R. Rajagopal
Styrene–Butadiene–Styrene, the modifier used in PMB-E, for instance, shows two transitions, one at C due to polybutadiene and another between 60 C and 70C due to polystyrene when blended with polybutadiene (Masson et al.2005b). The glass transition temperature of both Polystyrene (PS) and Polybutadiene (PB) are expected to further shift when blended with bitumen. The frequency-independent tan δ for PMB-E is observed in the range of 55–65C. Considering the fact that no such frequency independence of tan δ is observed for the unmodified bitumen, the transition occurring in the temperature range of 55-65C can be associated with SBS, in specific, the PS in SBS (Masson, Bundalo-Perc, and Delgado 2005a). Though literature explaining such behaviour for CRMB is scarce, one can make similar arguments and associate the frequency independent tan δ observed in CRMB to the rubber constituent in crumb rubber. Estimation of the transition temperature from frequency independence of tan δ is associated with the response of the polymer rather than the base bitumen.