Controlled Synthesis of Siloxane Polymers and Siloxane-Siloxane Block Copolymers with 3-Chloropropyl Groups Pendant to the Siloxane Chain

Abstract

Linear polysiloxanes bearing 3‐chloropropyl groups pendant to the polymer chain and containing a vinyl functional group at one chain end were synthesized by anionic ring polymerizations of 2,4,6‐tri(3‐chloropropyl)‐2,4,6‐trimethylcyclotrisiloxane, 1, and 2‐(3‐chloropropyl)‐2,4,4,6,6‐pentamethylcyclotrisiloxane, 2, initiated with butyl lithium or lithium silanolate in tetrahydrofuran. The polymerizations led to high yields of polymers with narrow molecular weight distributions. The precise functionalizations of the polymers were performed by a termination method quenching the polymerization by dimethylvinylchlorosilane. Diblock copolymers AB of narrow molecular weight distribution and a high topological purity were obtained by the sequential anionic copolymerization of hexamethylcyclotrisiloxane, D3, with monomers 1 and 2.

Copolymerization of functional cyclotrisiloxanes – a reactivity comparison

“…The route C(a) is a commonly used procedure for making these monomers [25]. However it gives poor yields when X = chloropropyl and in this case the method C(b) appeared to be more effective [11].…”

“…The most common precursor group used in the anionic polymerization of cyclosiloxanes is the vinyl group [10]; chloropropyl and hydrogen groups were also used with caution [11,12].…”

Electrochemical‐Reduction‐Assisted Assembly of a Polyoxometalate/Graphene Nanocomposite and Its Enhanced Lithium‐Storage Performance

“…In this case, the sequential anionic polymerization of hexamethylcyclotrisiloxane and 2,4,6‐(3‐chloropropyl)‐2,4,6‐trimethylcyclotrisiloxane initiated with BuLi was exploited. The reaction has been described elsewhere 11…”

“…The diblock copolymer of DMS (A) and 3‐halogenopropylmethylsiloxane (B), 3a , was synthesized by the anionic sequential copolymerization of hexamethylcyclotrisiloxane and 2,4,6‐tri(3‐chloropropyl)‐2,4,6‐trimethylcyclotrisiloxane, as previously reported 11. According to the SEC analysis, 3a had M n = 10,900 g mol −1 and M w / M n = 1.08.…”

“…It is based on a cheap substrate that is manufactured on a broad scale, (3‐chloropropyl)methyldichlorosilane. The synthesis of various polymers and copolymers of 3‐chloropropylmethylsiloxane (CPMS) starting from this monomer is well elaborated10, 11 and opens the possibility of the synthesis of QAS‐containing polysiloxanes of various controlled structures.…”