Coordinative Chain Transfer Copolymerization and Terpolymerization of Conjugated Dienes

Abstract

The coordinative chain transfer co-and ter-polymerizations of myrcene, isoprene and styrene have been achieved using Cp*La(BH 4 ) 2 (THF) 2 (Cp* = pentamethylcyclopentadienyl) combined with magnesium dialkyl and aluminum dialkyl. New highly stereoregular poly(myrcene-co-styrene), poly(myrcene-co-isoprene), and poly(myrcene-co-isoprene-co-styrene) copolymers have been obtained with good yields and a wide range of compositions. The concept of coordinative chain transfer polymerization (CCTP) induced control of the microstructure of statistical copolymers could be successfully extended to 1,4conjugated dienes statistical copolymerization and terpolymerization and to a renewable monomer. In addition to significant transmetalation in the course of the polymerization, a modification of the apparent comonomers reactivity ratio was observed in the presence of a chain transfer agent. This could be combined, depending on the nature of the chain transfer agent, with either a stereospecific polymerization of both conjugated dienes or the introduction of 3,4 enchainments in the microstructure. The former 1,4-trans stereoselective homo-, co-, and terpolymerizations enable the growth of several stereoregular chains per catalyst atom, providing significant catalyst economy, at the expense of the activity however. The latter affords an easy and straightforward modification of the microstructure of conjugated dienes co-and terpolymers in terms of both composition and regioregularity. This is particularly interesting regarding long and tedious catalysts synthesis required to reach the same array of polymeric materials via a classical living approach.

Stereoselective Copolymerization of Styrene with Terpenes Catalyzed by an Ansa-Lanthanidocene Catalyst: Access to New Syndiotactic Polystyrene-Based Materials

“…On the other hand, all poly(S-co-Fa) samples were white powders. The catalyst productivity decreased with an increase of the cases of styrene/β-myrcene and styrene/farnesene copolymerization, respectively, entries 4-10 and entries [13][14][15][16][17]; this is consistent with the fact that 1 is poorly active towards β-myrcene and farnesene homopolymerization (entries 1-2 and 11-12). On the other hand, as the [terpene] 0 /[St] 0 feed ratio was raised, the terpene content in the resulting copolymers increased as expected; thus, a wide range of compositions was obtained (My content = 5.6-30.8 mol % and Fa content = 1.5-9.8 mol %).…”

“…DSC (differential scanning calorimetry) analyses revealed a T g of ca. −58 • C, consistent with a 50:50 ratio of 1,4-and 3,4-segments [4,15]. Farnesene homopolymerization was also explored (Table 1, entries 11 and 12); however, the productivities were even lower than for β-myrcene homopolymerization (0.28-0.34 kg·mol −1 ·h −1 ) and a lower monomer loading was required to recover some poly(Fa) (i.e., [Fa] NMR data recorded for the recovered polymer were consistent with those reported in the literature [6,19], and revealed a poly(Fa) microstructure made of a mixture of 1,4-and 3,4-insertions (Supporting Information, Figures S6 and S7).…”

“…A few examples of styrene-myrcene polymers have already been reported, mostly via anionic or radical copolymerizations [12][13][14]. To our knowledge, only one paper has addressed the coordination copolymerization of styrene with β-myrcene (My) in the presence of the ternary system Cp * La(BH 4 ) 2 (THF) 2 /nBuEtMg/AliBu 3 , affording poly(S-co-1,4-trans-My) containing high amounts of myrcene (66-96 mol %) [15]. Yet, nothing has been reported about styrene-myrcene copolymers containing stereoregular PS sequences, nor about the copolymerization of styrene with β-farnesene.…”

Recent Progress in Sustainable Polymers Obtained from Cyclic Terpenes: Synthesis, Properties, and Application Potential

“…[55] In addition to radicala nd ionic methods, coordinativec haintransfer copolymerization and terpolymerizationo ft he conjugated dienes 9,i soprene, and styrene have recently been described by meanso fametallocene complex combined with magnesium anda luminum alkyl compounds, resulting in stereoregular copolymers ( Figure 2B). [56] In the presenceo f ac hain-transfer reagent, significant transmetalation during polymerization, asw ell as am odification of the apparent monomer reactivity ratio, was observed. Either stereospecific polymerization of both conjugated dienes or the introduction of 3,5-enchainments in the microstructures was accomplished, depending on the nature of the transfer reagent.…”

“…B) Coordinative chain-transferp olymerization (CCTP) of conjugated dienes (the top two are terpene based). [56] ChemSusChem 2015, 8,2455 -2471 www.chemsuschem.org…”