Über die herstellung von makromolekülen mit funktionellen endgruppen 1. Mitt.

Greber, Von Gerd; Balciunas, Alberto

doi:10.1002/macp.1963.020690115

Cited by 23 publications

(5 citation statements)

References 15 publications

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“…This reaction proceeds efficiently to form the macromonomer in quantitative yield. [22][23][24] Asami and co-workers 15 investigated the effect of solvent and temperature on the direct reaction of poly(styryl)lithium with VBC. Quantitative macromonomer synthesis was achieved when THF (17 vol %) was added to poly(styryl)lithium before addition to a 13 M excess of VBC in THF at -10 °C.…”

Section: Introductionmentioning

confidence: 99%

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Efficient Synthesis of ω-(p-Vinylbenzyl)polystyrene by Direct Functionalization of Poly(styryl)lithium with p-Vinylbenzyl Chloride in Hydrocarbon Solvent with Lithium 2,3-Dimethyl-3-pentoxide

et al. 2006

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The direct functionalization of poly(styryl)lithium (M n ≈ 2000 g/mol) with p-vinylbenzyl chloride (VBC) has been investigated in hydrocarbon solvent. With a 9-fold excess of VBC and normal addition, the predominant product (55% yield) was the corresponding head-to-head dimer; the macromonomer was formed in only 20% yield as determined by 1 H NMR analysis. MALDI-TOF MS analysis of the products showed that the other major side reaction products resulted from addition of PSLi to the vinyl group of VBC. However, in the presence of excess lithium halides (LiCl, LiBr) the amount of dimer formation was reduced (30%), but the yield of macromonomer was increased only slightly (27%). The principal impurity was the corresponding nonfunctional polystyrene attributed to hydrogen abstraction from VBC by PSLi. A high yield (g98%) of ω-(p-vinylbenzyl)polystyrene macromonomer was obtained when the functionalization was effected in the presence of 10 equiv of lithium 2,3-dimethyl-3-pentoxide. No dimer formation was observed by SEC analysis, but the presence of a small amount (e2%) of nonfunctional polystyrene was detected by MALDI-TOF MS analysis of the product.

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Section: Introductionmentioning

confidence: 99%

“…ω-( p -Vinylbenzyl)-functionalized macromonomers have been prepared without end-capping by terminating poly(styryl)lithium and poly(styryl)sodium with p -vinylbenzyldimethylchlorosilane. This reaction proceeds efficiently to form the macromonomer in quantitative yield. − …”

Section: Introductionmentioning

confidence: 99%

Efficient Synthesis of ω-(p-Vinylbenzyl)polystyrene by Direct Functionalization of Poly(styryl)lithium with p-Vinylbenzyl Chloride in Hydrocarbon Solvent with Lithium 2,3-Dimethyl-3-pentoxide

et al. 2006

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“…Unfortunately, the reactivity of the siloxanolate anion is much less than that of the styryl anion and so SiO cannot be used to reinitiate styrene polymerization. As a consequence of this, a coupling reaction (Greber, 1963(Greber, , 1964, using a dichlorosiloxane, has to be employed finally to form the ABA copolymer. The reaction is illustrated in the scheme below.…”

Section: Methodsmentioning

confidence: 99%

Styrene-Siloxane ABA Block Copolymers. Synthesis and Dilute Solution Properties

Davies¹,

Jones²

1971

Product R&D

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Narrow molecular weight distribution (Mw/M" ~1.3) polystyrene (A)-polydimethylsiloxane (6) ABA block copolymers have been prepared using anionic polymerization techniques. These copolymers are structurally similar to polystyrene-polybutadiene block copolymers, as they possess well-defined block segments. The narrowness of their molecular weight distribution was confirmed by direct measurement of Mw and Mn and by gel permeation chromatography. Light scattering, using the Benoit and Krause approach to copolymer solutions, osmometry, and viscometry were used to study the molecular parameters of these block copolymers. The evidence from both light scattering and viscometry suggests that the preferred configuration of the copolymers in solution is that of randomly interpenetrating coils.

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“…Some researchers have introduced a PS component into PDMS by synthesizing PS‐ b ‐PDMS and PDMS‐ g ‐PS copolymers. For example, Morton et al10 synthesized a PS‐ b ‐PDMS copolymer by the ring‐opening polymerization of cyclic polysiloxanes with polystyryl potassium; Greber et al11 prepared a graft copolymer by anionic polymerization of styrene (St) with a macromolecular catalyst having a polysiloxane chain; Minoura et al12 prepared block and graft copolymers by the chain‐tranfer reaction of chlorosilyl compounds in the radical polymerization of St. In these copolymers, the soft PDMS component is chemically linked to the glassy PS segment, which plays a crucial role in enhancing the mechanical properties of the elastomer system.…”

Section: Introductionmentioning

confidence: 99%

Preparation, morphology, and mechanical properties of elastomers based on α,ω‐dihydroxy‐polydimethylsiloxane/polystyrene blends

Dong

Liu

Han

et al. 2004

J of Applied Polymer Sci

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␣,-Dihydroxy-polydimethylsiloxane/polystyrene (PDMS/PS) blends were prepared by the solution polymerization of styrene (St) in the presence of ␣, -dihydroxy-polydimethylsiloxane (PDMS), using toluene as solvent and benzoyl peroxide (BPO) as initiator. The PDMS/PS blends obtained by this method are a series of stable, white gums, which were vulcanized to elastomers at room temperature with methyl-triethoxysilicane (MTES). The use level of MTES was far more than the necessary amount used to end-link hydroxy-terminated chains of PDMS, with the excess being hydrolyzed to crosslinked networks, which were similar to SiO 2 and acted as filler. Investigations were carried out on the elastomeric materials by extraction measurement, swelling measurement, and scanning electron microscopy. The extraction data show that at each composition the amount of soluble fraction is less than expected and the difference between experimental and theoretical values becomes more and more significant as PS content increases. This is mainly due to the grafting of PS onto PDMS and the entanglement of PS in the interpenetrating polymer network (IPN), which consists of either directly linked PDMS chains or chains linked via PS grafts and is formed by free radical crosslinking of PDMS during the radical polymerization of St. PS grafted on PDMS is insoluble and PS entangled in the IPN is difficult to extract. Both render the soluble fraction to be less than expected. As the St content in preparing PDMS/PS blends increases, the probability of grafting PS onto PDMS also increases, which may subsequently produce a higher crosslinking level of PDMS networks that linked via PS grafts by radical crosslinking. As a result, not only the amount of insoluble PS increases but also PS entangled in the IPN is more difficult to extract. Scanning electron microscopy demonstrates that the elastomer system has a microphase-separated structure and a certain amount of PS remains in the PDMS networks after extraction, which is in accordance with the extraction data. Moreover, the mechanical properties of the elastormeric materials have been studied in detail.

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Über die herstellung von makromolekülen mit funktionellen endgruppen 1. Mitt.

Cited by 23 publications

References 15 publications

Efficient Synthesis of ω-(p-Vinylbenzyl)polystyrene by Direct Functionalization of Poly(styryl)lithium with p-Vinylbenzyl Chloride in Hydrocarbon Solvent with Lithium 2,3-Dimethyl-3-pentoxide

Efficient Synthesis of ω-(p-Vinylbenzyl)polystyrene by Direct Functionalization of Poly(styryl)lithium with p-Vinylbenzyl Chloride in Hydrocarbon Solvent with Lithium 2,3-Dimethyl-3-pentoxide

Styrene-Siloxane ABA Block Copolymers. Synthesis and Dilute Solution Properties

Preparation, morphology, and mechanical properties of elastomers based on α,ω‐dihydroxy‐polydimethylsiloxane/polystyrene blends

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