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Bernard Boutevin - One of the best experts on this subject based on the ideXlab platform.
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telomerization of Acrylic Acid with mercaptans part 2 kinetics of the synthesis of star shaped macromolecules of Acrylic Acid
Polymer International, 2001Co-Authors: Cedric Loubat, Bernard BoutevinAbstract:The telomerization of Acrylic Acid with a polyfunctional transfer agent initiated by 2,2′-azobisisobutyronitrile, was first investigated in an organic medium (THF) at 65 °C. Transfer constants (CT) for three mercaptans, ethylene glycol bisthioglycolate, trimethylolpropane tris(2-mercaptoacetate) and pentaerythritol tetrakis(3-mercaptopropionate) of about 6.1, 6.3 and 7.3, respectively, were determined. From these results, it followed that a well-defined star poly(Acrylic Acid) could not be synthesized via telomerization of Acrylic Acid in THF. Nevertheless, the same study was performed with the tetrafunctional transfer agent in water/THF mixtures. This work emphasized that the nature of the solvent plays an important role in determining the transfer constant. Thus, the value of CT for the tetrafunctional transfer agent decreased from 7.3 in THF to 1, the ‘ideal’ case for telomerization (CT ≈ 1), for the mixture of solvents water/THF (80%, 20%, v/v). With this route, it seems that Acrylic Acid star-shaped macromolecules could be synthesized via telomerization. © 2001 Society of Chemical Industry
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Telomerization of Acrylic Acid with mercaptans: Part 2. Kinetics of the synthesis of star‐shaped macromolecules of Acrylic Acid
Polymer International, 2001Co-Authors: Cedric Loubat, Bernard BoutevinAbstract:The telomerization of Acrylic Acid with a polyfunctional transfer agent initiated by 2,2′-azobisisobutyronitrile, was first investigated in an organic medium (THF) at 65 °C. Transfer constants (CT) for three mercaptans, ethylene glycol bisthioglycolate, trimethylolpropane tris(2-mercaptoacetate) and pentaerythritol tetrakis(3-mercaptopropionate) of about 6.1, 6.3 and 7.3, respectively, were determined. From these results, it followed that a well-defined star poly(Acrylic Acid) could not be synthesized via telomerization of Acrylic Acid in THF. Nevertheless, the same study was performed with the tetrafunctional transfer agent in water/THF mixtures. This work emphasized that the nature of the solvent plays an important role in determining the transfer constant. Thus, the value of CT for the tetrafunctional transfer agent decreased from 7.3 in THF to 1, the ‘ideal’ case for telomerization (CT ≈ 1), for the mixture of solvents water/THF (80%, 20%, v/v). With this route, it seems that Acrylic Acid star-shaped macromolecules could be synthesized via telomerization. © 2001 Society of Chemical Industry
C.e. Park - One of the best experts on this subject based on the ideXlab platform.
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Effect of Acrylic Acid content in poly(ethylene-ran-Acrylic Acid) on the morphology and mechanical properties of poly(ethylene-ran-Acrylic Acid)/polystyrene blends compatibilized by poly(styrene-ran-glycidyl methacrylate)
Polymer, 1997Co-Authors: Sanghyo Kim, Jin Kon Kim, C.e. ParkAbstract:Abstract Three poly(ethylene-ran-Acrylic Acid)s (PE-AAs) with different amounts of Acrylic Acid but exhibiting similar rheological properties were studied to investigate the effect of Acrylic Acid content in PE-AAs on the morphology and mechanical properties of PE-AA/polystyrene (PS) blend compatibilized by poly(styrene-ran-glycidyl methacrylate) (PS-GMA). From morphological observations, there appears to be an optimum amount of Acrylic Acid in PE-AA that effectively reduces the dispersed domain size in PE-AA/PS blend systems. The existence of an optimum value is due to the combined effects of a sufficient reaction near the interface giving enough amounts of graft copolymers as a compatibilizer between PE-AA and PS, and fast diffusion of reactive species toward the interface. However, the tensile strength (σb) and the elongation at break (ϵb) for these blend systems steadily increased with an increase in the amount of Acrylic Acid in PE-AA. By increasing the amount of PS-GMA, σb and ϵb for all blend systems increased rapidly, and then levelled off. Impact strength of these blend systems was investigated by varying them amount of Acrylic Acid in PE-AA.
Cedric Loubat - One of the best experts on this subject based on the ideXlab platform.
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telomerization of Acrylic Acid with mercaptans part 2 kinetics of the synthesis of star shaped macromolecules of Acrylic Acid
Polymer International, 2001Co-Authors: Cedric Loubat, Bernard BoutevinAbstract:The telomerization of Acrylic Acid with a polyfunctional transfer agent initiated by 2,2′-azobisisobutyronitrile, was first investigated in an organic medium (THF) at 65 °C. Transfer constants (CT) for three mercaptans, ethylene glycol bisthioglycolate, trimethylolpropane tris(2-mercaptoacetate) and pentaerythritol tetrakis(3-mercaptopropionate) of about 6.1, 6.3 and 7.3, respectively, were determined. From these results, it followed that a well-defined star poly(Acrylic Acid) could not be synthesized via telomerization of Acrylic Acid in THF. Nevertheless, the same study was performed with the tetrafunctional transfer agent in water/THF mixtures. This work emphasized that the nature of the solvent plays an important role in determining the transfer constant. Thus, the value of CT for the tetrafunctional transfer agent decreased from 7.3 in THF to 1, the ‘ideal’ case for telomerization (CT ≈ 1), for the mixture of solvents water/THF (80%, 20%, v/v). With this route, it seems that Acrylic Acid star-shaped macromolecules could be synthesized via telomerization. © 2001 Society of Chemical Industry
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Telomerization of Acrylic Acid with mercaptans: Part 2. Kinetics of the synthesis of star‐shaped macromolecules of Acrylic Acid
Polymer International, 2001Co-Authors: Cedric Loubat, Bernard BoutevinAbstract:The telomerization of Acrylic Acid with a polyfunctional transfer agent initiated by 2,2′-azobisisobutyronitrile, was first investigated in an organic medium (THF) at 65 °C. Transfer constants (CT) for three mercaptans, ethylene glycol bisthioglycolate, trimethylolpropane tris(2-mercaptoacetate) and pentaerythritol tetrakis(3-mercaptopropionate) of about 6.1, 6.3 and 7.3, respectively, were determined. From these results, it followed that a well-defined star poly(Acrylic Acid) could not be synthesized via telomerization of Acrylic Acid in THF. Nevertheless, the same study was performed with the tetrafunctional transfer agent in water/THF mixtures. This work emphasized that the nature of the solvent plays an important role in determining the transfer constant. Thus, the value of CT for the tetrafunctional transfer agent decreased from 7.3 in THF to 1, the ‘ideal’ case for telomerization (CT ≈ 1), for the mixture of solvents water/THF (80%, 20%, v/v). With this route, it seems that Acrylic Acid star-shaped macromolecules could be synthesized via telomerization. © 2001 Society of Chemical Industry
Milan Marić - One of the best experts on this subject based on the ideXlab platform.
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Effect of Acrylic Acid neutralization on ‘livingness’ of poly[styrene‐ran‐(Acrylic Acid)] macro‐initiators for nitroxide‐mediated polymerization of styrene
Polymer International, 2008Co-Authors: Benoît H. Lessard, Milan MarićAbstract:BACKGROUND: The effect of Acrylic Acid neutralization on the degradation of alkoxyamine initiators for nitroxide-mediated polymerization (NMP) was studied using styrene/Acrylic Acid and styrene/sodium acrylate random copolymers (20 mol% initial acrylate feed concentration) as macro-initiators. The random copolymers were re-initiated with fresh styrene in 1,4-dioxane at 110 °C at SG1 mediator/BlocBuilder® unimolecular initiator ratios of 5 and 10 mol%. RESULTS: The value of kpK (kp = propagation rate constant, K = equilibrium constant) was not significantly different for styrene/Acrylic Acid and styrene/sodium acrylate compositions at 110 °C (kpK = 2.4 × 10−6–4.6 × 10−6 s−1) and agreed closely with that for styrene homopolymerization at the same conditions (kpK = 2.7 × 10−6–3.0 × 10−6 s−1). All random copolymers had monomodal, narrow molecular weight distributions (polydispersity index Mw/Mn = 1.10–1.22) with similar number-average molecular weights Mn = 19.3–22.1 kg mol−1. Re-initiation of styrene/Acrylic Acid random copolymers with styrene resulted in block copolymers with broader molecular weight distributions (Mw/Mn = 1.37–2.04) compared to chains re-initiated by styrene/sodium acrylate random copolymers (Mw/Mn = 1.33). CONCLUSIONS: Acrylic Acid degradation of the alkoxyamines was prevented by neutralization of Acrylic Acid and allowed more SG1-terminated chains to re-initiate the polymerization of a second styrenic block by NMP. Copyright © 2008 Society of Chemical Industry
Sanghyo Kim - One of the best experts on this subject based on the ideXlab platform.
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Effect of Acrylic Acid content in poly(ethylene-ran-Acrylic Acid) on the morphology and mechanical properties of poly(ethylene-ran-Acrylic Acid)/polystyrene blends compatibilized by poly(styrene-ran-glycidyl methacrylate)
Polymer, 1997Co-Authors: Sanghyo Kim, Jin Kon Kim, C.e. ParkAbstract:Abstract Three poly(ethylene-ran-Acrylic Acid)s (PE-AAs) with different amounts of Acrylic Acid but exhibiting similar rheological properties were studied to investigate the effect of Acrylic Acid content in PE-AAs on the morphology and mechanical properties of PE-AA/polystyrene (PS) blend compatibilized by poly(styrene-ran-glycidyl methacrylate) (PS-GMA). From morphological observations, there appears to be an optimum amount of Acrylic Acid in PE-AA that effectively reduces the dispersed domain size in PE-AA/PS blend systems. The existence of an optimum value is due to the combined effects of a sufficient reaction near the interface giving enough amounts of graft copolymers as a compatibilizer between PE-AA and PS, and fast diffusion of reactive species toward the interface. However, the tensile strength (σb) and the elongation at break (ϵb) for these blend systems steadily increased with an increase in the amount of Acrylic Acid in PE-AA. By increasing the amount of PS-GMA, σb and ϵb for all blend systems increased rapidly, and then levelled off. Impact strength of these blend systems was investigated by varying them amount of Acrylic Acid in PE-AA.