Influence of 1,2 units content on the hydrogenation of polydienes by TSH

Santin, Cristiane Krause; Jacobi, Marly Antônia Maldaner; Schuster, R. H.

doi:10.1002/app.32775

Cited by 3 publications

(3 citation statements)

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“…Catalytic hydrogenation is the conventional one, but it has some drawbacks such as: ( i ) the high cost of the equipment, ( ii ) the use of expensive hydrogenation conditions, which are mostly associated with high pressure reactors and expensive catalyst, and ( iii ) the low efficiencies resulting from limited solubility of the reagents. Alternatively, the hydrogenation of unsaturated polymers by a non-catalytic way, in which the reaction is promoted by diimide (diazene, NH=NH), has been shown to be an attractive process and extremely efficient in the case of 1,3-diene polymers [ 36 , 37 ].…”

Section: Resultsmentioning

confidence: 99%

Isotactic and Syndiotactic Alternating Ethylene/Propylene Copolymers Obtained Through Non-Catalytic Hydrogenation of Highly Stereoregular cis-1,4 Poly(1,3-diene)s

et al. 2017

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The homogeneous non-catalytic hydrogenation of cis-1,4 poly(isoprene), isotactic cis-1,4 poly(1,3-pentadiene) and syndiotactic cis-1,4 poly(1,3-pentadiene) with diimide, formed by thermal decomposition of para-toluenesulfonylhydrazide, is examined. Perfectly alternating ethylene/propylene copolymers having different tacticity (i.e., isotactic and syndiotactic), which are difficult to synthesize by stereospecific copolymerization of the corresponding monomers, are obtained. Both isotactic and syndiotactic alternating ethylene/propylene copolymers are amorphous, with very low glass transition temperatures.

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Section: Resultsmentioning

confidence: 99%

Isotactic and Syndiotactic Alternating Ethylene/Propylene Copolymers Obtained Through Non-Catalytic Hydrogenation of Highly Stereoregular cis-1,4 Poly(1,3-diene)s

et al. 2017

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“…exert the decisive effect on the properties of PB. The relationship between the parameters (c, t, v) and properties of PB is still at the focus of researchers' attention [3][4][5][6][7]. In this case, the question arises as to whether the determination of the above parameters is correct [6].…”

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confidence: 95%

Determination of configurational isomers in polybutadienes by 1H and 13C NMR spectroscopy

Makhiyanov

2012

Polym. Sci. Ser. A

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In the polymerization of 1,3 butadiene, chain growth occurs via addition of the monomer at 1,2 or 1,4 positions; in the latter case, cis 1,4 and trans 1,4 configurations can form.It is well known [1,2] that the configurational-iso metric composition (c, t, v) along with other micro structure parameters (monomer unit distributions in a chain, average length of monomer block sequences, specific content of possible combinations of units, etc.) exert the decisive effect on the properties of PB. The relationship between the parameters (c, t, v) and properties of PB is still at the focus of researchers' attention [3][4][5][6][7]. In this case, the question arises as to whether the determination of the above parameters is correct [6].The structure of PB is investigated with the use of such nondestructive methods as vibrational spectros copy (IR and Raman) [8][9][10][11][12][13][14][15] and high resolution NMR . In research and industrial laborato ries, IR spectroscopy is the most popular method owing to its accessibility and simplicity. However, for quantitative measurements, this method requires cali bration [13] and is inferior to NMR spectroscopy in informative value. Over the past half century, the structure of PB has been intensively studied with the use of NMR spectroscopy: high resolution 1 H [16-36] and 13 C [33, 37-73] NMR spectroscopy of liquid (dissolved) samples, solid state 13 C NMR spectros copy [74][75][76], and two dimensional spectroscopy [73,[77][78][79]. Despite the considerable progress of mag netic resonance techniques, solid state and multidi mensional variants are still inferior to "classical" (i.e., liquid one dimensional) NMR for solving quantita tive problems. Therefore, our study concerns only the potential of the latter method for estimating the values of c, t, and v for polybutadiene.The use of NMR spectroscopy for the quantitative analysis of the structure of PB was discussed in [11,17,30,51,59,60]. However, this problem is still topical. First, the requirements imposed on the informative level and accuracy of the NMR method [80-82], including those for the study of polymers [83], are increasing steadily. Second, a widespread opinion about the completeness of assignment and easy analy sis of the spectra of PB as the simplest diene polymer is contrary to reality [6, 71-73, 79, 84].The goal of this study is to solve a complex of meth odological problems arising during determination of the isomeric composition of PB with the use of NMR spectroscopy. EXPERIMENTALCommercial PBs (DOW SE BR 1202D, BUNA CB 530T, DOW SE PB 5800, SKDN and SKD L rubbers manufactured by OAO Nizhnekam skneftekhim, and SKB and SKD 2 manufactured by the Kazan and Efremov synthetic rubber plants, respectively) and laboratory samples PB 11, PB 15, PB 35, PB 38, PB 55, and PB 67 were used in this study. Laboratory samples were synthesized with the use of a lithium containing initiation system, as described in [84]. The PB samples were dissolved in chloroform d and benzene d 6 (the solution concen tration was 1 wt %) when th...

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“…With regards to the properties of SBS and hydrogenated SBS, it has been demonstrated that the composition of the elastomeric block and the overall copolymer architecture play an important role in determining their thermal and mechanical properties .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of poly (styrene‐b‐[(butadiene)_1−x‐(ethylene‐co‐butylene)_x] ‐b‐styrene) star‐like molecular polymers produced by partial hydrogenation of SBS

Xicohtencatl-Serrano

Garcia-Leiner

Cabrera-Ortiz

et al. 2013

Polymer Engineering & Sci

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, 04510 M exico DF, MexicoThis article reports the synthesis and characterization of four arm star-shaped poly(styrene-b-[(butadiene) 12x -(ethylene-co-butylene) x ]-b-styrene) (SBEBS) copolymers. A series of SBEBS copolymers with different compositions of the elastomeric block were produced by hydrogenating a given poly(styrene-b-butadiene-b-styrene) (SBS) copolymer using a catalyst prepared from bis(g 5 -cyclopentadienyl)titanium(IV) dichloride and nbutyllithium. The characterization was accomplished by proton nuclear magnetic resonance spectroscopy ( 1 H NMR), infrared spectroscopy (FTIR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). The results indicate that there is a selective saturation of the polybutadiene block over the polystyrene block; this selectivity was determined by the Ti/Li molar ratio and the concentration of Ti. It was observed that the saturation rate of the 1,2-vinyl was higher than that of the 1,4-trans and 1,4-cis poly(butadiene)-b isomers. The DSC and DMA results indicate that the degree of hydrogenation had a profound effect on the polymer's relaxation behavior. All samples exhibited a biphasic system behavior with two distinct transitions corresponding to the elastomeric and polystyrene blocks. SBEBS copolymers with higher saturation levels (>33%) exhibited a crystalline character. The TGA results indicated a characteristic weight loss temperature in all samples, with slightly higher thermal degradation stabilities in the materials with higher degrees of saturation.

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Influence of 1,2 units content on the hydrogenation of polydienes by TSH

Cited by 3 publications

References 18 publications

Isotactic and Syndiotactic Alternating Ethylene/Propylene Copolymers Obtained Through Non-Catalytic Hydrogenation of Highly Stereoregular cis-1,4 Poly(1,3-diene)s

Isotactic and Syndiotactic Alternating Ethylene/Propylene Copolymers Obtained Through Non-Catalytic Hydrogenation of Highly Stereoregular cis-1,4 Poly(1,3-diene)s

Determination of configurational isomers in polybutadienes by 1H and 13C NMR spectroscopy

Synthesis and characterization of poly (styrene‐b‐[(butadiene)_1−x‐(ethylene‐co‐butylene)_x] ‐b‐styrene) star‐like molecular polymers produced by partial hydrogenation of SBS

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Influence of 1,2 units content on the hydrogenation of polydienes by TSH

Cited by 3 publications

References 18 publications

Isotactic and Syndiotactic Alternating Ethylene/Propylene Copolymers Obtained Through Non-Catalytic Hydrogenation of Highly Stereoregular cis-1,4 Poly(1,3-diene)s

Isotactic and Syndiotactic Alternating Ethylene/Propylene Copolymers Obtained Through Non-Catalytic Hydrogenation of Highly Stereoregular cis-1,4 Poly(1,3-diene)s

Determination of configurational isomers in polybutadienes by 1H and 13C NMR spectroscopy

Synthesis and characterization of poly (styrene‐b‐[(butadiene)1−x‐(ethylene‐co‐butylene)x] ‐b‐styrene) star‐like molecular polymers produced by partial hydrogenation of SBS

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Synthesis and characterization of poly (styrene‐b‐[(butadiene)_1−x‐(ethylene‐co‐butylene)_x] ‐b‐styrene) star‐like molecular polymers produced by partial hydrogenation of SBS