Dynamic Mechanical Behavior of Polystyrene-(Ethene-co-butene)-Polystyrene, Triblock Copolymer Films Cast from Various Solvents

Cowie, J. M. G.; Lath, D.; McEwen, I.J.

doi:10.1021/ma60067a011

Cited by 23 publications

(14 citation statements)

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“…Short ethylene sequences observed by 13 C n.m.r. (Figure 5) are responsible for this behaviour, in good agreement with the observations reported for SEBS triblock copolymers [19]. As shown in Tables 1 and 2, T g 2 for the hydrogenated triblock copolymers (HA1-HA4) is higher than T g 2 for the original MBM copolymers, which is thought to result from a more complete phase separation.…”

Section: Dsc Analysissupporting

confidence: 89%

Synthesis and characterization of hydrogenated poly[alkylmethacrylate(-b-styrene)-b-butadiene-b-(styrene-b-) alkylmethacrylate] triblock and pentablock copolymers

Yu¹,

Yu²,

Dubois³

et al. 1997

Polymer

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Triblock and pentablock copolymers of the X(Y)B(Y)X type have been synthesized by the sequential living anionic polymerization of butadiene (B), styrene (Y) and alkylmethacrylate (X), respectively. The diadduct of tBuLi onto m-diisopropenylbenzene (m-DIB) has been used as a difunctional initiator. Methylmethacrylate (MMA), t-butylmethacrylate (tBMA) and isobornylmethacrylate (IBMA) have been used as precursors of the outerblocks X. The polybutadiene (PBD) midblock that contains ca 42-45% 1,2-units has been selectively hydrogenated into a saturated poly(ethylene-co-1-butene) (PEB) block. The homogeneous hydrogenation catalysis has no deleterious effect on the copolymer integrity. These completely soluble thermoplastic elastomers have been characterized by FT i.r., n.m.r., d.s.c. and d.m.a. The PEB midblock has a low T g (-50°C) and a small propensity to crystallize. The effect of hydrogenation on the morphology and mechanical properties depends on the outer block. Upon hydrogenation of the PBD midblock in polymethylmethacrylate (PMMA) and polyisobornylmethacrylate (PIBMA) containing triblock copolymers, the ultimate tensile strength is increased (except for a hard block content > 50%) due to a sharper phase separation, whereas the elongation at break is decreased. The extent of phase separation is reduced in polyt-butylmethacrylate(PtBMA) containing triblock copolymers upon hydrogenation and the ultimate tensile strength is slightly decreased. Stereocomplexation of the syndiotactic PMMA outerblocks is observed to occur upon blending with isotactic PMMA

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Section: Dsc Analysissupporting

confidence: 89%

Synthesis and characterization of hydrogenated poly[alkylmethacrylate(-b-styrene)-b-butadiene-b-(styrene-b-) alkylmethacrylate] triblock and pentablock copolymers

Yu¹,

Yu²,

Dubois³

et al. 1997

Polymer

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“…When samples B1 and B3 are hydrogenated (HB1 and HB3: Table ), a broad, ill-defined melting endotherm is observed above T g 1 , with a maximum close to −7 °C. So the PEB component can crystallize, although with formation of a small number of poorly defined crystalline domains as previously reported, and discussed elsewhere . The melting enthalpy is quite comparable for HB1 and HB3, thus unaffected by the hard block content.…”

Section: Resultssupporting

confidence: 72%

Poly[poly(isobornyl methacrylate-co-methyl methacrylate) (poly(IBMA-co-MMA))-b-polybutadiene-b-poly(IBMA-co-MMA)] Copolymers: Synthesis, Morphology, and Properties

Dubois

Jérôme

1997

Macromolecules

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Anionic random and block copolymerization of isobornyl methacrylate (IBMA) and methyl methacrylate (MMA) has been studied in THF at −78 °C by using (1,1-diphenyl-3,3-dimethylbutyl)lithium (DDBLi) as initiator in the presence of LiCl. The random copolymerization of MMA and IBMA has also been carried out at 0 °C, all the other conditions being kept unchanged. Poly[poly(IBMA)-b-poly(BD)-b-poly(IBMA)] (IBI), poly[poly(IBMA-co-MMA)-b-poly(BD)-b-poly(MMA-co-IBMA)] (I/MBM/I), and poly[poly(IBMA)-b-poly(MMA)-b-poly(BD)-b-poly(MMA)-b-poly(IBMA)] (IMBMI) block copolymers have been synthesized by sequential anionic polymerization of butadiene, MMA, and IBMA initiated by the m-diisopropenylbenzene (m-DIB)/tert-butyllithium (t-BuLi) diadduct. These block copolymers of a monomodal and narrow molecular weight distribution (M̄ w/M̄ n = 1.1) have been analyzed by size exclusion chromatography (SEC), NMR, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and transmission electron microscopy (TEM). Stereocomplexation of IMBMA and I/MBM/I with iPMMA has also been studied by DSC. Although IBI triblock copolymers show a lamellar morphology even for relatively low hard block content (33 wt %), cylindrical and lamellar morphologies have been observed for the other block copolymers under consideration. These new block copolymers exhibit high ultimate tensile strength (30 MPa), elongation at break (1000%), and upper service temperature (140−200 °C).

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“…In case of sample HD, a broad, ill-defined melting endotherm is observed above T g1 , with a diffuse maximum close to −7 °C, which indicates a small number of poorly defined crystalline domains in the PEB matrix. Crystallization originates from short polyethylene blocks delimited by butylene units . Hydrogenation of the MBM copolymer D results in a 10 °C increase in T g2 (Table ), which indicates that the phase separation becomes sharper upon hydrogenation.…”

Section: Resultsmentioning

confidence: 99%

Poly[alkyl methacrylate-b-butadiene-b-alkyl methacrylate] Triblock Copolymers: Synthesis, Morphology, and Mechanical Properties at High Temperatures

Dubois

Jérôme

1996

Macromolecules

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Block copolymers of the ABA type, where B is polybutadiene (PBD) and A is poly(ethyl methacrylate) (PEMA), poly(tert-butyl methacrylate) (P-t-BMA), poly(methyl methacrylate) (PMMA), or poly(isobornyl methacrylate) (PIBMA), have been successfully synthesized by sequential anionic polymerization of butadiene and methacrylates with the diadduct of tert-butyllithium to m-diisopropenylbenzene as a difunctional initiator. Block copolymers of a narrow molecular weight distribution (1.10) have been analyzed by differential scanning calorimetry, transmission electron microscopy, and dynamic mechanical analysis. These materials are phase-separated and have high mechanical performances. Special attention has been paid to the service temperature of these thermoplastic elastomers in comparison with a styrene−butadiene−styrene (SBS) triblock copolymer. The upper service temperature (UST) has been estimated from the temperature dependence of the tensile properties in the 25−150 °C range and found to change with the outer blocks. Polystyrene (T g = 100°C) is at the origin of the lower UST, which is however comparable to PEMA (T g = 90 °C) and P-t-BMA (T g = 116 °C) containing triblock copolymers of similar molecular weight and composition. PMMA (T g = 132 °C) outer blocks increase the UST of the triblocks, which is further increased by hydrogenation of the PBD midblock. The higher UST has been found for a PIBMA (T g = 202 °C)-containing triblock copolymer that shows an ultimate tensile strength higher than 2 MPa at 150 °C.

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Dynamic Mechanical Behavior of Polystyrene-(Ethene-co-butene)-Polystyrene, Triblock Copolymer Films Cast from Various Solvents

Cited by 23 publications

References 0 publications

Synthesis and characterization of hydrogenated poly[alkylmethacrylate(-b-styrene)-b-butadiene-b-(styrene-b-) alkylmethacrylate] triblock and pentablock copolymers

Synthesis and characterization of hydrogenated poly[alkylmethacrylate(-b-styrene)-b-butadiene-b-(styrene-b-) alkylmethacrylate] triblock and pentablock copolymers

Poly[poly(isobornyl methacrylate-co-methyl methacrylate) (poly(IBMA-co-MMA))-b-polybutadiene-b-poly(IBMA-co-MMA)] Copolymers: Synthesis, Morphology, and Properties

Poly[alkyl methacrylate-b-butadiene-b-alkyl methacrylate] Triblock Copolymers: Synthesis, Morphology, and Mechanical Properties at High Temperatures

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