Organolanthanides, catalysts for specific olefin-diene copolymerization: access to new materials

Recent Advances in Rare Earth Complexes Bearing Allyl Ligands and Their Reactivity towards Conjugated Dienes and Styrene Polymerization

“…In terms of reactivity, the allyl moiety is of specific interest because it makes it possible to carry out a certain number of elementary organometallic reactions, such as those involved in catalytic processes (insertion reactions [9], hydrogenolysis [10,11], hydrosilylation [12], alkyl exchange [13], etc.). Consequentially, the [RE-(allyl)] species has demonstrated its ability to catalyze polymerization reactions, with a particular behavior towards non-polar monomers (Scheme 1), some of which are highly stereo-selective [14][15][16]. The [RE-(allyl)] moiety has also been studied as a model for the chain initiation in olefin polymerization [17], and the coordination of the allyl ligand within the complexes, as well as the specificity of the rare earth metals used have shown to vary the outcome of the polymerizations.…”

Copolymerization of 1-hexene and 1-dodecene with 1,3-butadiene by a versatate/diisobutylaluminum hydride/t-butyl chloride catalyst system

“…This was expected, since according to the literature [26] the influence on material properties becomes more significant only with comonomers having at least 10 carbon atoms. Nevertheless, the reduction in the propagation constant because of the stereo hindrance provoked by dodecene-1 was so strong that with the reaction time used in this work (2 hours), no polymer was obtained from the addition of 5% wt of dodecene-1.…”

Synthesis and characterization of butadiene-1,3 and octene-1 copolymer prepared by a Ziegler-Natta catalyst based on neodymium

“…From the results obtained by FTIR, Table 1 shows that the microstructure of copolymers formed did not change with the variation of alpha-olefin content. This behavior was expected because with the presence of terminal olefins, such as octene-1, it is possible to obtain a copolymer with no changes in the structure of the material [16,26] . The literature [14,[16][17]23] shows that the number average molecular mass (Mn) and weight average molecular mass (Mw) of copolymers, under the same conditions, should increase with the increasing of alpha-olefin content incorporated in the polybutadiene chain, as shown in Figure 2.…”

“…Although these catalyst systems produce a polymer with good mechanical properties, especially higher tensile strength, lower heat buildup, and better abrasion resistance, the polymer chains are highly linear, which make difficult the processability of the material [1][2][3][4][5][6][7][8] . Some procedures can be carried out to improve the processability of polydienes, such as the insertion of some branches into polymer chain [3,[9][10][11][12] , copolymerization of dienes with oligomers [13] , copolymerization of dienes and α-olefin with different lengths chains [14][15][16] , insertion of branches with chain-end functionalized [17][18][19][20][21][22][23][24][25][26] . Visseaux et al [14] copolymerized isoprene with α-olefins of different lengths (from 6 to 18 carbons) and concluded that only a single chain of α-olefin was inserted between two units of trans-polyisoprene.…”

“…The short branches, under stress, escape easily from the entanglements and align with the polymer chain, provoking a softening under stretching [2] . Barbier-Baudry et al [16] utilized a non-hindered ansa dicyclopentadienylallyl complexes of samarium, [(CMe 2 C 5 H 4 ) 2 Sm(allyl)] n , and (CMe 2 C 5 H 4 ) 2 Sm(allyl)L (L = THF or allylLi) to polymerize isoprene without an aluminum cocatalyst. The results showed that the polymerizations were highly stereospecific, affording nearly quantitatively 1-4 trans polyisoprene.…”