Abstract : Sulfonated block copolymer ionomers possessing short (1K g/mol) styrene blocks and var... more Abstract : Sulfonated block copolymer ionomers possessing short (1K g/mol) styrene blocks and various rubber block lengths were synthesized via sequential anionic polymerization of styrene, isoprene, and styrene followed by hydrogenation and sulfonation. The ionomers were then characterized by small-angle x-ray scattering (SAXS) and atomic force microscopy (AFM). The SAXS data indicate the presence of microphase-separated sulfonated styrene domains within the rubber phase. The morphology of the phase separation in this system is not clear from SAXS due to the absence of higher order maxima. Increased Bragg spacing was observed as the rubber block molecular weights increased, but decreased upon neutralization of the sulfonic acid groups with sodium hydroxide. The intensity of the SAXS maxima increased for shorter rubber block segments. AFM images confirmed the presence of microphase-separated domains which appear spherical.
The present invention is at least two polymer end blocks A, but contains a polymer interior block... more The present invention is at least two polymer end blocks A, but contains a polymer interior block B of at least one kind, each A block resistant to sulfonation polymer block, easy-polymer block to each of the B blocks are sulfonated in, this A block and B blocks do not contain significant levels of olefinic unsaturation, to a solid block copolymer. Each A block is a polymerized (i) para-substituted styrene monomers, (ii) ethylene, (iii) the carbon atom 3 to 18 alpha olefin; (Iv) 10 hydrogenated 1,3-cyclodiene monomers, (v) hydrogenated monomers of conjugated dienes having a vinyl content of less than 35mol% prior to hydrogenation, (vi) acrylic esters, (vii) methacrylic esters, and (viii) containing at least one segment is selected from the mixtures thereof and each B block is (i) unsubstituted styrene monomers, (ii) ortho-substituted styrene monomers, (iii) meta-substituted styrene monomers, (iv) alpha-methylstyrene , (v) 1,1- diphenyl preferably contains ethylene, (vi) 1,2- diphenylethylene and (vii) one or more segments of polymerized vinyl aromatic monomer is selected from a mixture thereof. In addition, they provide a variety of end-use and the field of use of such a block copolymer manufacturing method, such a block copolymer of the polymer. Polymer end blocks, the polymer interior blocks, the sulfonated block copolymers
ABSTRACT Phosphonium ion-containing acrylate triblock (ABA) copolymers were synthesized using nit... more ABSTRACT Phosphonium ion-containing acrylate triblock (ABA) copolymers were synthesized using nitroxide mediated radical polymerization. The polymerization of styrenic phosphonium-containing ionic liquid monomers using a difunctional alkoxyamine initiator, DEPN2, afforded an ABA triblock copolymer with an n-butyl acrylate soft center block (DP 400) and symmetric phosphonium-containing external reinforcing blocks (DP < 30). Two phosphonium monomers with different alkyl substituent lengths enabled an investigation of the effects of ionic aggregation of phosphonium cations on the physical properties of ABA block copolymer ionomers. Subsequently, the thermomechanical properties and morphologies of these materials were compared to a noncharged triblock copolymer analogue with neutral polystyrene external blocks. Shortening the alkyl substituents on the phosphonium cation enhanced the hydrophilicity of tributyl-4-vinylbenzyl phosphonium chloride (BPCl) relative to trioctyl-4-vinylbenzyl phosphonium chloride (OPCl). In both cases, phosphonium cations promoted microphase-separation and thermoplastic elastomer performance for the OPCl- and BPCl-containing triblock copolymers compared to a less well-defined, microphase segregated morphology for the styrene analogue. Dynamic mechanical analysis (DMA) of phosphonium-containing triblock copolymers exhibited well-defined rubbery plateau regions, whereas the plateau was shortened for the nonionic analogue. The solid state morphologies of the block copolymers were studied using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM), and both techniques revealed phase separation at the nanoscale. DMA studies indicated that phosphonium aggregation governed flow activation energies.
A novel acid-cleavable diacrylate crosslinker, DCDA, was used as a difunctional Michael acceptor ... more A novel acid-cleavable diacrylate crosslinker, DCDA, was used as a difunctional Michael acceptor in the synthesis of acid-cleavable crosslinked networks via base-catalyzed Michael addition of telechelic poly(ethylene glycol) bis(acetoacetate). Michael addition networks containing DCDA were degraded in the presence of catalytic quantities of acids to form soluble polymeric products. Michael addition networks of non-degradable diacrylate crosslinkers were chemically unchanged under identical reaction conditions and remained insoluble. Thermal degradation of DCDA-containing networks was also investigated using TGA, which confirmed the thermal reactivity and concentration of the acid-labile crosslink points.
Abstract : Sulfonated block copolymer ionomers possessing short (1K g/mol) styrene blocks and var... more Abstract : Sulfonated block copolymer ionomers possessing short (1K g/mol) styrene blocks and various rubber block lengths were synthesized via sequential anionic polymerization of styrene, isoprene, and styrene followed by hydrogenation and sulfonation. The ionomers were then characterized by small-angle x-ray scattering (SAXS) and atomic force microscopy (AFM). The SAXS data indicate the presence of microphase-separated sulfonated styrene domains within the rubber phase. The morphology of the phase separation in this system is not clear from SAXS due to the absence of higher order maxima. Increased Bragg spacing was observed as the rubber block molecular weights increased, but decreased upon neutralization of the sulfonic acid groups with sodium hydroxide. The intensity of the SAXS maxima increased for shorter rubber block segments. AFM images confirmed the presence of microphase-separated domains which appear spherical.
The present invention is at least two polymer end blocks A, but contains a polymer interior block... more The present invention is at least two polymer end blocks A, but contains a polymer interior block B of at least one kind, each A block resistant to sulfonation polymer block, easy-polymer block to each of the B blocks are sulfonated in, this A block and B blocks do not contain significant levels of olefinic unsaturation, to a solid block copolymer. Each A block is a polymerized (i) para-substituted styrene monomers, (ii) ethylene, (iii) the carbon atom 3 to 18 alpha olefin; (Iv) 10 hydrogenated 1,3-cyclodiene monomers, (v) hydrogenated monomers of conjugated dienes having a vinyl content of less than 35mol% prior to hydrogenation, (vi) acrylic esters, (vii) methacrylic esters, and (viii) containing at least one segment is selected from the mixtures thereof and each B block is (i) unsubstituted styrene monomers, (ii) ortho-substituted styrene monomers, (iii) meta-substituted styrene monomers, (iv) alpha-methylstyrene , (v) 1,1- diphenyl preferably contains ethylene, (vi) 1,2- diphenylethylene and (vii) one or more segments of polymerized vinyl aromatic monomer is selected from a mixture thereof. In addition, they provide a variety of end-use and the field of use of such a block copolymer manufacturing method, such a block copolymer of the polymer. Polymer end blocks, the polymer interior blocks, the sulfonated block copolymers
ABSTRACT Phosphonium ion-containing acrylate triblock (ABA) copolymers were synthesized using nit... more ABSTRACT Phosphonium ion-containing acrylate triblock (ABA) copolymers were synthesized using nitroxide mediated radical polymerization. The polymerization of styrenic phosphonium-containing ionic liquid monomers using a difunctional alkoxyamine initiator, DEPN2, afforded an ABA triblock copolymer with an n-butyl acrylate soft center block (DP 400) and symmetric phosphonium-containing external reinforcing blocks (DP < 30). Two phosphonium monomers with different alkyl substituent lengths enabled an investigation of the effects of ionic aggregation of phosphonium cations on the physical properties of ABA block copolymer ionomers. Subsequently, the thermomechanical properties and morphologies of these materials were compared to a noncharged triblock copolymer analogue with neutral polystyrene external blocks. Shortening the alkyl substituents on the phosphonium cation enhanced the hydrophilicity of tributyl-4-vinylbenzyl phosphonium chloride (BPCl) relative to trioctyl-4-vinylbenzyl phosphonium chloride (OPCl). In both cases, phosphonium cations promoted microphase-separation and thermoplastic elastomer performance for the OPCl- and BPCl-containing triblock copolymers compared to a less well-defined, microphase segregated morphology for the styrene analogue. Dynamic mechanical analysis (DMA) of phosphonium-containing triblock copolymers exhibited well-defined rubbery plateau regions, whereas the plateau was shortened for the nonionic analogue. The solid state morphologies of the block copolymers were studied using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM), and both techniques revealed phase separation at the nanoscale. DMA studies indicated that phosphonium aggregation governed flow activation energies.
A novel acid-cleavable diacrylate crosslinker, DCDA, was used as a difunctional Michael acceptor ... more A novel acid-cleavable diacrylate crosslinker, DCDA, was used as a difunctional Michael acceptor in the synthesis of acid-cleavable crosslinked networks via base-catalyzed Michael addition of telechelic poly(ethylene glycol) bis(acetoacetate). Michael addition networks containing DCDA were degraded in the presence of catalytic quantities of acids to form soluble polymeric products. Michael addition networks of non-degradable diacrylate crosslinkers were chemically unchanged under identical reaction conditions and remained insoluble. Thermal degradation of DCDA-containing networks was also investigated using TGA, which confirmed the thermal reactivity and concentration of the acid-labile crosslink points.
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