Preparation and characterization of syndiotactic polystyrene/ethylene‐propylene copolymer blends

Choi, Won‐Mook; Park, Cheon-Il; Park, O Ok; Lim, Jae-Gon

doi:10.1002/app.10768

Cited by 8 publications

(4 citation statements)

References 21 publications

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“…It is well known that block copolymers can work as effective compatibilizers for immiscible polymer blends 39, 40. In fact, there have been many studies aimed at improving the inherent low impact strength of commercial syn ‐PS through blending with rubbery or elastic materials such as ethylene/propylene rubber or ST–BD–ST copolymers 41–44. To investigate the potential of the stereoregular PS–PB block copolymers obtained in this work, we created a series of binary syn ‐PS/ cis ‐PB blends with the addition of various amounts of the stereoregular syn ‐PS‐ b ‐ cis ‐PB copolymer.…”

Section: Resultsmentioning

confidence: 99%

Stereospecific sequential block copolymerizations of styrene and 1,3‐butadiene with a C₅Me₅TiMe₃/B(C₆F₅)₃/Al(oct)₃ catalyst

Tsunogae¹,

Shiono

2005

J. Polym. Sci. A Polym. Chem.

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This article reports a new methodology for preparing highly stereoregular styrene (ST)/1,3-butadiene (BD) block copolymers, composed of syndiotactic polystyrene (syn-PS) segments chemically bonded with cis-polybutadiene (cis-PB) segments, through a stereospecific sequential block copolymerization of ST with BD in the presence of a C 5 Me 5 TiMe 3 /B(C 6 F 5 ) 3 /Al(oct) 3 catalyst. The first polymerization step, conducted in toluene at Ϫ25°C, was attributed to the syndiospecific living polymerization of ST. The second step, conducted at Ϫ40°C, was attributed to the cis-specific living polymerization of BD. The livingness of the whole polymerization system was confirmed through a linear increase in the weight-average molecular weights of the copolymers versus the polymer yields in both steps, whereas the molar mass distributions remained constant. The profound cross reactivity of the styrenic-end-group active species with BD toward ST led to the production of syn-PS-b-cis-PB copolymers with extremely high block efficiencies. Because of the presence of crystallizable syn-PS segments, this copolymer exhibited high melting temperatures (up to 270°C), which were remarkably different from those of the corresponding anionic ST-BD copolymers, for which no melting temperatures were observed. Scanning electron microscopy pictures of a binary syn-PS/cis-PB blend with or without the addition of the syn-PS-b-cis-PB copolymers proved that it could be used as an effective compatibilizer for noncompatibilized syn-PS/cis-PB binary blends.

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Section: Resultsmentioning

confidence: 99%

Stereospecific sequential block copolymerizations of styrene and 1,3‐butadiene with a C₅Me₅TiMe₃/B(C₆F₅)₃/Al(oct)₃ catalyst

Tsunogae¹,

Shiono

2005

J. Polym. Sci. A Polym. Chem.

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“…The component may be a suitable block or graft copolymer or functional polymer, which are capable of acting as interfacial agents 20. It is well known that block copolymers can be effective compatibilizers for immiscible polymer blends containing sPS21–27 or epoxy resins 28, 29…”

Section: Introductionmentioning

confidence: 99%

Influence of PS‐b‐PEO diblock copolymers on the compatibility of syndiotactic polystyrene modified epoxy blends

Tercjak

Serrano

Martín

et al. 2006

J of Applied Polymer Sci

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Homogeneous solutions of syndiotactic polystyrene (sPS) in diglycidylether of bisphenol A (DGEBA), containing 2.5, 5 and 7.5 wt % of thermoplastic with or without 0.5 and 1 wt % of poly(styrene-b-ethylene oxide) (PS-b-PEO) block copolymer, were polymerized using a stoichiometric amount of an aromatic amine hardener, 4,4Ј-methylene bis (3-chloro-2,6-diethylaniline) (MCDEA). The dynamic-mechanical properties and morphological changes of sPS-(DGEBA/MCDEA) compatibilized with different amount of PS-b-PEO have been investigated in this paper. The addition of the block copolymer produced significant changes in the morphologies generated. The size of the dispersed spherical sPS spherulites does not change significantly, but less spherulites of sPS appeared upon network formation in the systems with compatibilizer, what means that addition of compatibilizer in this system delayed crystallization of sPS in sPS-(DGEBA/MCDEA) systems and change phase separation mechanism from crystallizationinduced phase separation (CIPS) and reaction-induced phase separation (RIPS) almost only to RIPS. Moreover, PS-b-PEO with higher molecular weight of PS block seems to be a more effective compatibilizer than one with lower molecular weight of PS block.

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“…Although sPS has many desirable properties as an engineering thermoplastic, its main disadvantage is its low impact strength. Therefore, improvements in the impact strength are very essential to the expansion of its various applications 2–4…”

Section: Introductionmentioning

confidence: 99%

Effect of diblock copolymers on morphology and mechanical properties for syndiotactic polystyrene/ethylene‐propylene copolymer blends

Choi

Park

Lim

2004

J of Applied Polymer Sci

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ABSTRACT:Interfacial agents are often used to compatibilize immiscible polymer blends. They are known to reduce the interfacial tension, homogenize the morphology, and improve adhesion between phases. In this study, two diblock copolymers of styrene/ethylene-propylene (SEP), which have different molecular weights, were used to compatibilize a blend of syndiotactic polystyrene (sPS) 75% and ethylene-propylene rubber (EPR) 25% so as to extend the applications of sPS as incoming thermoplastics. The morphological analysis and emulsification curve, which relates the average size of the dispersion particles to the concentration of diblock copolymers added, was used to investigate the efficiency of the interfacial agents on the blend morphology. A notched izod impact test and a tensile test were also performed to determine the compatibilization effect of different molecular weight copolymers on the mechanical properties of the blends and to establish links between morphology and mechanical properties. Results suggest that the lower molecular weight diblock copolymer showed an effective emulsifying capacity for sPS/ERP immiscible blend in morphology and mechanical properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3618 -3626, 2004

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Preparation and characterization of syndiotactic polystyrene/ethylene‐propylene copolymer blends

Cited by 8 publications

References 21 publications

Stereospecific sequential block copolymerizations of styrene and 1,3‐butadiene with a C₅Me₅TiMe₃/B(C₆F₅)₃/Al(oct)₃ catalyst

Stereospecific sequential block copolymerizations of styrene and 1,3‐butadiene with a C₅Me₅TiMe₃/B(C₆F₅)₃/Al(oct)₃ catalyst

Influence of PS‐b‐PEO diblock copolymers on the compatibility of syndiotactic polystyrene modified epoxy blends

Effect of diblock copolymers on morphology and mechanical properties for syndiotactic polystyrene/ethylene‐propylene copolymer blends

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Preparation and characterization of syndiotactic polystyrene/ethylene‐propylene copolymer blends

Cited by 8 publications

References 21 publications

Stereospecific sequential block copolymerizations of styrene and 1,3‐butadiene with a C5Me5TiMe3/B(C6F5)3/Al(oct)3 catalyst

Stereospecific sequential block copolymerizations of styrene and 1,3‐butadiene with a C5Me5TiMe3/B(C6F5)3/Al(oct)3 catalyst

Influence of PS‐b‐PEO diblock copolymers on the compatibility of syndiotactic polystyrene modified epoxy blends

Effect of diblock copolymers on morphology and mechanical properties for syndiotactic polystyrene/ethylene‐propylene copolymer blends

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Stereospecific sequential block copolymerizations of styrene and 1,3‐butadiene with a C₅Me₅TiMe₃/B(C₆F₅)₃/Al(oct)₃ catalyst

Stereospecific sequential block copolymerizations of styrene and 1,3‐butadiene with a C₅Me₅TiMe₃/B(C₆F₅)₃/Al(oct)₃ catalyst