A-B-A Triblock Copolymers

Noshay, Allen; McGrath, James E.

doi:10.1016/b978-0-12-521750-7.50011-x

Cited by 13 publications

(18 citation statements)

References 202 publications

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“…Block structures result in the introduction of stable nonhomogeneous segments within a polymer matrix and are essential for the assembly of macromolecular structures (38,40). An example is the widely used SBS (styrene-butadiene-styrene) triblock thermoplastic elastomer formed via anionic polymerization (39). Of course, the ultimate functional, block copolymers are proteins and DNA.…”

Section: Applicationsmentioning

confidence: 99%

“…Each polymer chain remains active ("alive") until the reaction is terminated by added reagents. The only well-documented examples of living polymerization are anionic (38), cationic (39), and group-transfer polymerization (40). These processes opened new control in polymer synthesis and, before the new ROMP catalysts, were the only methods to prepare block polymers and related structures ofwell-defined molecular weight.…”

Section: <11111mentioning

confidence: 99%

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Polymer Synthesis and Organotransition Metal Chemistry

Grubbs

Tumas

1989

Science

482

271

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Mechanistic and synthetic studies in organometallic chemistry have provided considerable insight into olefin metathesis and Ziegler-Natta polymerization. New homogeneous olefin metathesis catalysts based on high oxidation state transition metals have opened new opportunities in polymer synthesis by providing unprecedented control in ring-opening polymerization of cyclic alkenes. The recent development of living coordinative polymerization systems has led to the preparation of a number of new, interesting materials, including block copolymers, conducting polymers or precursors, and ionophoric polymeric substrates.

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Section: Applicationsmentioning

confidence: 99%

Section: <11111mentioning

confidence: 99%

Polymer Synthesis and Organotransition Metal Chemistry

Grubbs

Tumas

1989

Science

482

271

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“…From the amounts of reactants and Me2S0 shown in Tables I and 11, the product of the concentrations of amine and acyllactam groups in the dextran-polyamide coupling reaction (run no. 1 in Table 11) was estimated to be only a two hundredth of the corresponding product in the D-maltosepolyamide coupling (run no. 1 in Table I ) .…”

Section: Influence Of Hydroxyl Groups Upon the Anionic Polymerizationmentioning

confidence: 99%

“…1 v/v) . The resulting colorless polymer was collected by centrifugation at room temperature, washed carefully with the mixed solvent several times, and dried in vacuo: yield of 8,2.50 g; M , 2700; functionality of acyllactam group, 0.97.To a solution of 8 (0.49 g ) in Me2S0 (1.6 mL) 0.36 g of ethylenediamine was added, and the mixture was stirred at 25°C for 2 h. After excess of eth-'H-NMR spectrum of the dextran-polyamide block copolymer (12c) (run no 1. inTable V, after deprotection) (5% MezSO-d6 solution; TMS; 80°C; 200 MHz) .…”

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confidence: 99%

“…ylenediamine and Me2S0 were distilled out with a rotary evaporator, the residue was added to a mixture of n-hexane and acetone( 2 : 1 v/v). The precipitate was collected by centrifugation and dried in vacuo; yield of 10, 0.44 g. The amino group in the polymer was determined by titration with 0.02 N perchloric acid in acetic acid under a nitrogen atmosphere using crystal violet as an indicator:34 M , value estimated by the titration, 3000.Coupling Reaction between D-Maitonolactone (15) and the Terminal Amine Group in the Polyamide (10)A mixture of 0.12 g of 15 and 0.47 g of 10 ( M n , 2500) was first dried in vacua in a 100 mL three necked round-bottom flask at room temperature for A GPC curves of polymers: (A) dextran derivative with an acyllactam group ( M , of parent dextran, 3600); ( B ) dextran-polyamide block copolymer (run no 1. in…”

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confidence: 99%

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Synthesis of block copolymer containing dextran and polyamide sequences

Hashimoto

Imanishi

Okada

et al. 1992

J. Polym. Sci. A Polym. Chem.

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A novel AB‐type block copolymer composed of dextran and polyamide sequences was prepared through the following two approaches. One is a coupling reaction of a terminal functional group introduced in the dextran chain with that in the polyamide chain, such as the reaction of an amine group with an acyllactam group or that of a lactone group with an amine group at the corresponding chain ends. The other is an anionic polymerization of a bicyclic lactam activated with a trimethylsilylated dextran derivative having an acyllactam end group. The latter procedure was found to be more effective for the preparation of the block copolymer having a high molecular weight polyamide sequence.

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Compatibility, adhesional interaction of components, impact strength, and rheological behavior of polycarbonate/polycarbonate-siloxane block copolymer

Песецкий¹,

Jurkowski

Koval³

2000

J. Appl. Polym. Sci.

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Polycarbonate (PC) blended with a polymer‐modifier polycarbonate–polydimethylsiloxane (PC–PDMS) of polyblock structure having equal molar ratios of soft (PDMS) and hard (PC) blocks have been investigated. The kinetics of adhesional interaction in blends and the analysis of interphase interaction conducted by using the relaxation spectrometry showed that intensive interactions between phases can occur. At a concentration of the modifier ≤5 wt %, these effects can lead to a partial compatibility of the components. The phase separation comes to completion when PC–PDMS content reaches 7 to 10 wt %. Here the impact strength of the blends improves compared with homopolycarbonate; this factor becomes less sensitive to the notch pattern or surface defects. The micro‐heterogeneous blends would fail by the multiple crazing mechanism. The mode of temperature vs impact strength relationship depends on the concentration of the modifier. Low shearing rates applied to the PC blends containing 3 to 7 wt % of PC–PDMS results in a lower melt flow index compared with that for a neat PC. The blends were more sensitive to shearing stresses than the homopolycarbonate. Therefore, they have lower viscosity at a high shearing rate than PC. Introduction of PC–PDMS into PC did not change its thermal stability significantly. The modifier inhibited the chemical crosslinking of PC chains if the melt had been kept for a long period. The optimal mechanical properties combined with improved processability were found in blends containing 7 to 10 wt % of PC–PDMS. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 858–869, 2000

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A-B-A Triblock Copolymers

Cited by 13 publications

References 202 publications

Polymer Synthesis and Organotransition Metal Chemistry

Polymer Synthesis and Organotransition Metal Chemistry

Synthesis of block copolymer containing dextran and polyamide sequences

Compatibility, adhesional interaction of components, impact strength, and rheological behavior of polycarbonate/polycarbonate-siloxane block copolymer

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