Thiol‐Ene Radical Addition of L‐Cysteine Derivatives to Low Molecular Weight Polybutadiene

Abstract

The functionalisation of a low molecular weight, liquid 1,2‐polybutadiene (PBL) was performed by the addition of either N‐acetyl‐L‐cysteine or its methyl ester through the thiol‐ene radical reaction. The functionalisation runs were carried out in 1,4‐dioxane solution and in the presence of a free radical initiator (2,2′‐azobisisobutyrronitrile, AIBN). The initial feed ratio polymer/cysteine derivative/initiator was varied, in order to highlight the occurrence of side reactions and to understand their possible influence on the process. The 1H NMR determination of the functionalisation degree brought out high addition degrees of thiols, regardless of the initial thiol/double bonds ratio. This caused a drastic change in the macroscopic properties of the PBL with improved solubility in hydrophilic solvents (for instance in alkaline aqueous solutions) and impressive increase of the glass transition temperature. The propagation of chiral properties from the functionalising agents to the modified polymers was evaluated by polarimetry and circular dichroism in solution.magnified image

Interfacial interaction modes construction of various functional SSBR–silica towards high filler dispersion and excellent composites performances

“…The thiol-ene click addition reaction mainly occurs between the 1,2-polybutadiene units and sulydryl. 12,22,23 Approximately 4.9% and 4.8% 1,2-polybutadiene units reacted with MPL and MUA; approximately 0.8%, 2.7%, and 4.8% 1,2-polybutadiene units reacted with MPTES in our experiment. There were approximately 70 MPL and 70 MUA molecules in each SSBR-g-MPL and SSBR-g-MUA, namely, SSBR-g-MPL70 and SSBR-g-MUA70.…”

In-chain functionalized syndiotactic 1,2-polybutadiene by a Ziegler–Natta iron(iii) catalytic system

“…In the past few years, colossal advances have been made for the former strategy, due to the presence of highly active pendent vinyl substituents. [16][17][18][19][20][21][22] For instance, Mecking, Ndoni, et al, presented efficient functionalization of sPB via thiol-ene reaction, through which various types of functional groups, including ester, L-cysteine, carboxylic acid were successfully introduced; [23][24][25] Linford and Tang reported hydrosilation and hydrozirconation of 1,2-polybutadiene (1,2-PB) by Si-H and Zr-H reagents, and provided a platform for accessing diversied functional 1,2-PBs. 26,27 Despite of the facility and efficiency in these reports, all of them were built on the sacrice of pendent double bonds, which might cause irreversible damage to the inherent nature of sPB, such as crystallinity, 28 molecular weights, 16 and even causing cross-linking.…”

“…Static water contact angle measurements for the resultant copolymer products (runs11,14,19,25).33470 | RSC Adv., 2019, 9, 33465-33471This journal is © The Royal Society of Chemistry 2019 RSC Advances Paper Open Access Article. Published on 17 October 2019.…”

Telechelic Polybutadienes or Polyisoprenes Precursors for Recyclable Elastomeric Networks

“…In the case of rubbers, furanic groups were grafted onto high molar mass polybutadiene, containing a high proportion of pendant vinylic groups, through thiol‐ene reaction forming a thermosensitive dynamic network by the addition of bismaleimide. Nevertheless, with thiol‐ene chemistry, side reactions like cyclization or uncontrolled irreversible crosslinking can occur, causing detrimental changes on the properties . Moreover, the use of high molar mass PB could be highly restrictive regarding the solubilization time and molding process of the material that can be hampered by high viscosity.…”