Selective hydrogenation of butadiene–styrene copolymers using a Ziegler–Natta type catalyst 2. Thermal properties

Escobar-Barrios, Vladimir Alonso; Petit, Alain; Pla, Fernand; Nájera, Rafael Herrera

doi:10.1016/s0014-3057(02)00380-4

Cited by 11 publications

(8 citation statements)

References 12 publications

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“…In addition, blends of PI with hPB and with PS homopolymers were also studied. In all the SBRs synthesized, TMEDA was added as a polar modifier to randomize the styrene–butadiene sequence as shown by Halasa and coworkers. , The butadiene units can be preferentially saturated over the styrene units using a variety of catalysts. ,,, For the SBRs, we employed a Li/Co catalyst which achieved ∼100% butadiene saturation (no detectable unsaturation by 1 H NMR) and ∼0% styrene saturation (no detectable saturation by 1 H NMR) within 5 h at 50 °C. The molecular weight distributions of a representative precursor SBR with 8.4 wt % styrene and its Li-/Co- saturated product, obtained from their elution traces, are shown in Figure ; these traces indicate that saturation proceeds without significant backbone rearrangements (scission or branching), with the reduction in “PS-equivalent” molecular weight resulting from a reduction in the polymer’s hydrodynamic volume in THF following saturation.…”

Section: Resultsmentioning

confidence: 99%

Blends of Polyisoprene with Model Styrene–Olefin Copolymers: Mixing Energetics in Blends versus Block Copolymers

et al. 2021

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Most theoretical treatments of polymer mixing thermodynamics assume that the phase behavior of both polymer blends and block copolymers is controlled by the same Flory segmental interaction parameter, χa quantity which is proportional to the interaction energy density, X. However, there are few comparative experimental studies on this point. This work presents a systematic experimental comparison between the interaction energy densities measured on model polydiene−polyolefin blends (X blend ) and analogous block copolymers (X BC ). Experimental cloud point temperature (T cl ) curves for blends of polyisoprene (PI) with selectively saturated poly(butadiene-r-styrene) (hSBR) random copolymers are fit to the Flory−Huggins theory, and the resultant values of X blend are corrected for critical fluctuations and for end-group contributions, wherever significant. The temperature-dependent PI/hSBR X blend (T) and previously reported PI−hSBR X BC values show satisfactory agreement at all levels of styrene incorporation, reinforcing the conclusion that random incorporation of styrene units into the saturated polybutadiene chain significantly enhances its compatibility with PI.

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Section: Resultsmentioning

confidence: 99%

Blends of Polyisoprene with Model Styrene–Olefin Copolymers: Mixing Energetics in Blends versus Block Copolymers

et al. 2021

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“…The UWP fiber is a semicrystalline material, and Fig. 7a shows the five diffraction peaks of WP fibers appearing at 14.8°, 17.0°, 19.7°, 22.3°, and 34.2° corresponding to the crystalline regions as cellulosic material [20, 21]. Figure 7b shows the peaks at the same 2θ values as UWP fibers with somewhat the same intensity due to the same fiber content as for the untreated sample (20 phr) and a low solid content of polystyrene emulsion.…”

Section: Resultsmentioning

confidence: 99%

Waste newsprint fibers for the reinforcement of radiation‐cured (styrene‐butadiene rubber)‐based composites. Part ii characterization and thermal properties

El‐Nemr

Ali

Hassan

2012

Vinyl Additive Technology

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Waste newsprint fibers were used as reinforcing fillers in composite materials based on a styrene-butadiene rubber matrix. Surface modification of the fibers was carried out by polystyrene emulsion treatment, and copolymerization with the rubber matrix was done by a radiation technique. Characterization of the modified surfaces and the adhesion between the treated newsprint paper fibers and the rubber matrix involved a variety of techniques, including X-ray diffraction, FTIR spectroscopy and differential scanning calorimetry, which revealed that the surface modification did occur and that it affected adhesion between the treated fibers and the rubber matrix upon irradiation. Thermogravimetric analysis indicated that the thermal stability of the fibers was enhanced by the treatment and that the thermal stability of irradiated composites was increased by the addition of treated newsprint fiber.

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“…This value was significantly lower than the T g at 100°C for a PS homopolymer of comparable molecular weight. The glass transition for the PS phase in thermoplastic elastomer block copolymer tends to be lower than that of pure homopolymer of the same chemical structure which is due to the entrapment of some centre block rubbery segments, a kinetic effect which is not thermodynamically favoured (Spaans &Williams, 1995;Escobar et al, 2003). This lowering effect is a consequence of premature molecular motions in the PS domain induced by PB segmental mobility.…”

Section: Thermal Properties Of a Sbs Copolymermentioning

confidence: 94%

Biomedical Engineering, Trends in Materials Science

Laskovski¹

2011

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Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published articles. The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book.

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Selective hydrogenation of butadiene–styrene copolymers using a Ziegler–Natta type catalyst 2. Thermal properties

Cited by 11 publications

References 12 publications

Blends of Polyisoprene with Model Styrene–Olefin Copolymers: Mixing Energetics in Blends versus Block Copolymers

Blends of Polyisoprene with Model Styrene–Olefin Copolymers: Mixing Energetics in Blends versus Block Copolymers

Waste newsprint fibers for the reinforcement of radiation‐cured (styrene‐butadiene rubber)‐based composites. Part ii characterization and thermal properties

Biomedical Engineering, Trends in Materials Science

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