Synthesis of polysiloxanes with electron‐donating groups by anionic ring‐opening polymerization

Chojnowski, Julian; Rózga, Krystyna; Fortuniak, Witold; Kowalewska, Anna

doi:10.1002/masy.19930730118

Cited by 8 publications

(11 citation statements)

References 31 publications

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“…[1 -3] The chlorine atom in c position to silicon is readily displaced by many nucleophiles, such as ammonia, and amines, [4,5] nitrile, [6] thiols and sulfides, [7 -9] azide, [10] carboxylates, [11] phosphines and phosphites [12] and others. Siloxane polymers bearing 3-chloropropyl substituents are used for the synthesis of interesting organofunctional polymers via transformation of the reactive haloalkyl group.…”

Section: Introductionmentioning

confidence: 99%

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

Fortuniak

Chojnowski²,

Sauvet³

2001

Macromol. Chem. Phys.

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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.

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Section: Introductionmentioning

confidence: 99%

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

Fortuniak

Chojnowski²,

Sauvet³

2001

Macromol. Chem. Phys.

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“…Thus, they could be applied for various purposes. They were used as efficient catalysts in homogeneous reaction systems, − phase transfer catalysts, polymeric ligands for anchoring transition metal catalysts, − intermediates for chemical reactions, − polymer electrolytes, , ion extractants, , and materials for chromatography, as well as for other applications …”

Section: Introductionmentioning

confidence: 99%

Controlled Synthesis of Siloxane Copolymers Having an Organosulfur Group by Polymerization of Cyclotrisiloxanes with Mixed Units

Rózga-Wijas¹,

Chojnowski²,

Zundel³

et al. 1996

Macromolecules

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The preparation of poly(dimethylsiloxane)s having part of the siloxane units substituted with a model organic thioether was investigated. The sulfur group was generated by the ene−thiol addition to the vinyl function bound to silicon. Two synthetic routes to this copolymer were compared (i) one-step kinetically controlled polymerization of organosulfur-substituted hexamethylcyclotrisiloxane and (ii) two-step synthesis including kinetically controlled polymerization of 1,3,3,5,5-pentamethyl-1-vinylcyclotrisiloxane followed by the thiol addition to the vinyl group in the polymer. A cryptand−lithium silanolate complex generated from [(trimethylsilyl)methyl]lithium was selected as the initiator in this polymerization, while tert-butyl mercaptan was used as the hydrosulfidation reagent. It was shown that synthesis routes lead to a high yield of copolymers having a fairly regular chain structure. The arrangement of siloxane units in the polymer chain was controlled by the propagation step. Polymerization of the vinyl-substituted monomer exhibited a significant degree of regioselectivity as one of the three possible modes of the monomer ring opening contributed over 70% to the propagation. Addition of t-BuSH to the vinyl group in the polymer proceeded without rearrangement of the polymer chain and could be performed without any side reaction of the vinyl group. Model copolymers of regular alternating structure were synthesized by the heterofunctional polycondensation of [2-(tert-butylthio)ethyl]methyldichlorosilane with a series of diols, HO(Me2SiO) n H, n = 1−4. They were used for comparison with the copolymers obtained by ring-opening polymerization.

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“…24–26 °C). The simultaneous slow addition of the two compounds used in the previously reported conventional syntheses of VD2 , and ClPD2 from dichlorosilanes and HO-D2-OH was not required because the reactions of the acetoxysilanes were not very fast, and the intramolecular cyclization of the intermediate 1-acetoxy-3-hydroxytrisiloxane was faster than the intermolecular condensation with another silanol or acetoxysilane. FnD2 was obtained in high purity after distillation of the crude products.…”

Section: Resultsmentioning

confidence: 99%

Precise Synthesis of Side-Chain-Functionalized Linear Polysiloxanes by Organocatalytic Ring-Opening Polymerization of Monofunctional Cyclotrisiloxanes

2021

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The organocatalytic controlled/living ring-opening polymerization (ROP) of monofunctional cyclotrisiloxanes using water or silanols as initiators, guanidines as catalysts, and organochlorosilanes as end-capping agents produced side-chainfunctionalized linear polysiloxanes with controlled number-average molar mass (M n ), narrow molar-mass dispersity (Đ M ), the desired terminal structures, and good distribution of the side-chain functionalities, namely, vinyl, 3-chloropropyl, and allyl groups. The synthesis of monofunctional cyclotrisiloxanes, such as v i n y l p e n t a m e t h y l c y c l o t r i s iloxane, (3-chlorop ropyl)pentamethylcyclotrisiloxane, and allylpentamethylcyclotrisiloxane was achieved by the reaction of 1,3-dihydroxy-1,1,3,3-tetramethyldisiloxane and diacetoxysilanes using simple synthetic procedures. Control over the composition and monomeric sequences of the resulting side-chain-functionalized polysiloxanes was conveniently achieved using either polymerization or copolymerization and varying the initial feed ratio of the two monomers and the timing of monomer addition, i.e., using either the premix or two-stage method, in the copolymerizations. Analysis of the monomeric sequence using 29 Si{ 1 H} NMR measurements revealed that the propagation reaction with VD2, ClPD2, and AD2 proceeded almost completely via a statistical manner. Plausible monomeric sequences and chain-length distributions of the resulting side-chainfunctionalized polysiloxanes were visualized using two simulation methods.

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Synthesis of polysiloxanes with electron‐donating groups by anionic ring‐opening polymerization

Cited by 8 publications

References 31 publications

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

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

Controlled Synthesis of Siloxane Copolymers Having an Organosulfur Group by Polymerization of Cyclotrisiloxanes with Mixed Units

Precise Synthesis of Side-Chain-Functionalized Linear Polysiloxanes by Organocatalytic Ring-Opening Polymerization of Monofunctional Cyclotrisiloxanes

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