Microstructure of polyisoprenes synthesized with titanium- and neodymium-containing catalytic systems

Rare-Earth-Metal Allyl Complexes Supported by the [2-(N,N-Dimethylamino)ethyl]tetramethylcyclopentadienyl Ligand: Structural Characterization, Reactivity, and Isoprene Polymerization

“…On the other hand, systematic incorporation of 3,4-units has been proven to influence the physicochemical properties of such rubbers, as has been shown for the increase in wet skid resistance coupled with balanced abrasion and rolling resistance properties of produced tire treads . However, the majority of publications on the structural NMR analysis of polyisoprenes have dealt with the incorporation of 3,4-units in polymers with pronounced cis-1,4-microstructure. − The catalytic system 2 / B /AlMe 3 (Table , run 15) produced polyisoprene with predominant trans-1,4-regularity but also featured 15% of 3,4-units as determined by 1 H NMR spectroscopy. The 13 C NMR gave sharp resonances for both the trans-1,4- ( T ) and the 3,4-units ( V ) but no indication of any cis-1,4-microstructures (signals at 23.4, 26.4, and 32.2 ppm in the aliphatic region) (Figure ).…”

“…65 However, the majority of publications on the structural NMR analysis of polyisoprenes have dealt with the incorporation of 3,4-units in polymers with pronounced cis-1,4-microstructure. 66 any cis-1,4-microstructures (signals at 23.4, 26.4, and 32.2 ppm in the aliphatic region) ( Figure 5).…”

Isoprene Polymerisation in the Presence of Catalytic Systems based on Gadolinium Compounds

“…Toluene was used as the eluent. The microstructure of the polymers was assessed from IR spectra (IR Fourier spectrophotometer), and here we confined ourselves to determining the 3,4-units, as it was established earlier that "rare-earth" cis-1,4-polyisoprene does not contain trans-1,4-units [3][4][5]. The number of polymer molecules formed in the polymerisation process was calculated by means of the formula:…”

“…The dependence of T m1 on the content of 3,4-units under 300% elongation Figure 3. The dependence of the number-average molecular weight M n on the monomer conversion with a DIBAH:Gd molar ratio of 5 (1), 10 (2), 15 (3), and 20 (4)…”

Synthetic Polyisoprene Rubber as a Mimic of Natural Rubber: Recent Advances on Synthesis, Nanocomposites, and Applications

“…Currently, the SR industry is based primarily on the polymers and copolymers of butadiene and styrene; however, polyisoprene and copolymers containing isoprene should not be overlooked. In 2022, world SR output reached 14.9 MMT [31], where IR represented almost 5% of the market [34]. As mentioned above, SR production dropped during COVID-19; nonetheless, as the pandemic eases, global SR production rebounds steadily and will hopefully reach 17.69 MMT by 2027 [35].…”