Synthesis and Properties of Block Polymers. I. Poly-α-methylstyrene-Polyisoprene-Poly-α-methylstyrene

Fetters, Lewis J.; Morton, Maurice

doi:10.1021/ma60011a002

Cited by 161 publications

(101 citation statements)

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“…This reaction must however be selective in the presence of PMMA [10,21]. 1 H NMR analysis of the original MTM and the final MnBM copolymers shows that there are no residual tBA groups in MnBM, although some of them have been hydrolyzed rather than transalcoholyzed (2-5%). Fig.…”

Section: Synthesismentioning

confidence: 99%

“…The use of diene-based TPEs is however limited by the poor oxidation resistance of the unsaturated central block and the relatively low service temperature (60-70°C) in relation to the glass transition temperature of polystyrene. Accordingly, efforts have been made to improve the properties of the outer [1][2][3][4][5][6] and/or the inner [2,7] blocks. Substitution of fully (meth)acrylate TPEs for the traditional SBS and SIS copolymers would be potentially beneficial due to the large range of properties of poly(meth)acrylates.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of poly(methyl methacrylate)-b-poly(n-butyl acrylate)-b-poly(methyl methacrylate) triblocks and their potential as thermoplastic elastomers

Tong

Jérôme

2000

Polymer

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A series of well defined poly(methyl methacrylate) (PMMA)-b-poly(n-butyl acrylate) (PnBA)-b-PMMA triblock copolymers (MnBM) has been synthesized by transalcoholysis of PMMA-b-poly(tert-butylacrylate) (PtBA)-b-PMMA precursors (MTM) by n-butanol. Phase separation is observed for all the investigated triblock copolymers, which contain PMMA outer blocks in the 5000-50 000 molecular weight (MW) range and PnBA inner blocks with MW in the 100 000-200 000 range. Although the ultimate tensile properties of these MnBM triblock copolymers are poor compared to traditional diene-based TPEs (SBS and SIS), they are much better than those ones reported for PMMA-b-poly(isooctyl acrylate) (PIOA)-b-PMMA triblocks (MIM). A reasonable explanation for this observation is found in the average molecular weight between chain entanglements (M e ) that has been estimated to be 28 000 for the central PnBA rubbery block, which is consistently much smaller than for PIOA (59 000) and substantially higher than M e for polybutadiene (1700) and polyisoprene (6100). The tensile behavior of MnBM copolymers cannot be fitted by either a simple elastomer model free from chain entanglements (suitable to MIM) or by a "filler" modified rubber model (suitable for diene-based TPEs), supporting the hypothesis that the mechanical properties of the investigated (meth)acrylate thermoplastic elastomers are significantly affected by any change in M e of the central acrylate block. Viscoelastic analysis shows that MnBM triblocks are of higher complex viscosity than the SBS and SIS analogs, leading to a shift in the order-disorder transition temperature to much higher temperature, unless the outer PMMA blocks are of very low molecular weight (5000).

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Section: Synthesismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis of poly(methyl methacrylate)-b-poly(n-butyl acrylate)-b-poly(methyl methacrylate) triblocks and their potential as thermoplastic elastomers

Tong

Jérôme

2000

Polymer

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“…T h e triblock elastomers are: styrenebutadiene-styrene (S B s); s tyrene-isoprene-styrene (SIS); and a-methylstyrene-isoprene-a-methylstyrene (mSImS). Values of AbUb were computed from data given by Morton and Fetters (64,65) on the triblock elastomers, by Vaughn (66) on the segmented siloxanecarbonate copolymers, and in Du Pont trade literature on the Adiprene elastomers. The cross-linked polyurethane elastomers are termed quasihomogeneous (5) because their polar (hard) segments, consisting of dipropylene glycol and toluene diisocyanate moieties, do not form plastic domains.…”

Section: For Both Elastomers [(Aand)mentioning

confidence: 99%

Strength of elastorners—a perspective

Smith

1977

Polymer Engineering & Sci

125

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The dependence of stress-strain curves on temperature and extension rate is first discussed qualitatively along with aspects of the fracture process. Considered thereafter are the strength and extensibility, measured over broad ranges of temperature and extension rate, of elastomers in several classes: (a) singlephase non-crystallizable; (b) crystallizable, both unfilled and containing a reinforcing filler; and (c) block copolymers which contain plastic domains. It is shown that all single-phase noncrystallizable elastomers lack toughness except under restricted test conditions and that toughness necessitates a dispersed phase. Data are presented on crystallizable rubber vulcanizates and on polyurethane and poly(urea-urethane) block copolymers to show that plastic domains are highly effective sources of strength. The properties of these block copolymers are examined in detail, and their strengths are compared with those of other segmented copolymers and triblock elastomers. Factors responsible for strength are delineated.

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“…Modification of the polydiene block in polystyrene-polydiene-polystyrene block copolymers has received much attention [35][36][37][38][39][40][41], including the selective hydrogenation of the midblock. Because the transition temperature from a rubbery gel to a plastic fluid (T P ) is too low for many applications, polystyrene has been either replaced by a higher T g block [42][43][44][45] or chemically modified [46][47]. An alternative strategy is the physical modification of one phase of the gel by appropriate additives.…”

Section: Introductionmentioning

confidence: 99%

Silica reinforced triblock copolymer gels

Theunissen

Overbergh

Reynaers

et al. 2004

Polymer

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The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has been investigated. Different types of chemically modified silica have been compared in order to evaluate the influence of the compatibility between gel and filler.Time-resolved SANS and small-angle X-ray scattering (SAXS) shows that the presence of silica particles affects the ordering of the polystyrene domains during gelsetting. The scattering pattern of silica-reinforced gels reveals strong scattering at very low q, but no structure and formfactor information. However, on heating above the viscoelastic to plastic transition, the 'typical' scattering pattern of the copolymer gel builds-up. All reinforced gels are strengthened by the addition of the reinforcing agent. The transitions from a viscoelastic rubber to a plastic fluid and from a plastic fluid to a viscoelastic liquid are shifted to more elevated temperatures when silica is added to the triblock copolymer gel.

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Synthesis and Properties of Block Polymers. I. Poly-α-methylstyrene-Polyisoprene-Poly-α-methylstyrene

Cited by 161 publications

References 0 publications

Synthesis of poly(methyl methacrylate)-b-poly(n-butyl acrylate)-b-poly(methyl methacrylate) triblocks and their potential as thermoplastic elastomers

Synthesis of poly(methyl methacrylate)-b-poly(n-butyl acrylate)-b-poly(methyl methacrylate) triblocks and their potential as thermoplastic elastomers

Strength of elastorners—a perspective

Silica reinforced triblock copolymer gels

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