Physically crosslinked elastomers prepared from oligomeric polyolefins with mesogenic units

Ikeda, Yuko; Inaki, Mototaka; Kidera, Akinori; Hayashi, Hisao

doi:10.1002/1099-0488(20000901)38:17<2147::aid-polb50>3.0.co;2-1

Cited by 9 publications

(12 citation statements)

References 18 publications

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“…We compared the tensile properties of the TLCP prepared by Ikeda et al with those of the MJLCP-based triblock copolymer. The performance of the MJLCP-based triblock copolymer is superior to those of the TLCP, especially for the elongation at break (only 51% for the TLCP).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

ABA Type Triblock Copolymer Based on Mesogen-Jacketed Liquid Crystalline Polymer: Design, Synthesis, and Potential as Thermoplastic Elastomer

Yi¹,

Fan²,

Wan³

et al. 2004

Macromolecules

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We have designed and successfully prepared a well-defined ABA type triblock copolymer consisting of poly(n-butyl acrylate) as soft B block and poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene} (PMPCS) as hard A block with potential as liquid crystalline thermoplastic elastomer (LCTPE). The synthetic strategy is to obtain a difunctional poly(n-butyl acrylate) first and then use it as a macroinitiator for chain extension. Both steps employ atom transfer radical polymerization (ATRP). Kinetic study of the chain-extension polymerization demonstrates a well-controlled process. The resulted triblock copolymers have high molecular weights (M n > 70 000) and low molecular weight distributions (M w/M n < 1.2). Their chemical structures are confirmed by nuclear magnetic resonance. Curves of differential scanning calorimetry indicate the immiscibility of the two components. Morphological investigations were made with transmission electrical microscopy and gave direct evidence of the existence of nanophase-separated structures with long-range order. After examinations by polarized optical microscopy, we found the triblock copolymers are LC only if the molecular weight of PMPCS block exceeds 20 000. Wide-angle X-ray diffraction measurements indicate a very stable nematic phase between glass transition of PMPCS block and decomposition. We found three samples are elastomeric. Preliminary mechanical tests were done on their films. Typical dynamic mechanical analysis and tensile tests prove that the sample has the potential as thermoplastic elastomers (TPEs). According to our best knowledge, the unique triblock copolymer is the first reported well-defined ABA type TPE imparting liquid crystallinity to the hard domains which serve as “physical cross-links”. Since the novel LC block copolymer has the rod−coil−rod conformation, it is also a new type of elastic rod−coil block copolymer.

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Section: Resultsmentioning

confidence: 99%

“…There was only one report of LCTPE with the sequence of LC/I/LC. Ikeda et al 17 synthesized an elastomeric twin liquid crystalline polymer (TLCP) consisting of a polyolefin oligomer with two terminal mesogenic groups. In the TLCP films, the polar mesogenic groups aggregate and separate into ordered nanodomains which behave as hard blocks.…”

Section: Introductionmentioning

confidence: 99%

ABA Type Triblock Copolymer Based on Mesogen-Jacketed Liquid Crystalline Polymer: Design, Synthesis, and Potential as Thermoplastic Elastomer

Yi¹,

Fan²,

Wan³

et al. 2004

Macromolecules

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“…Each gymnosome specimen was placed in an individual 5 ml styrene syringe containing filtered (0.45 µm pore size) seawater treated with streptomycin and neomycin (each 25 mg l −1 ). Clark polarographic oxygen electrodes (Clark 1956) formed an airtight seal at the end of the syringes, opposite the plunger, and care was taken to ensure no air bubbles were in the syringe (Ikeda et al 2000, Kawall et al 2001. Each electrode was calibrated using air-and nitrogen-saturated seawater at experimental temperature (Childress 1971).…”

Section: Respirometry (Oxygen Consumption Rates) and Ammonia Excretiomentioning

confidence: 99%

Metabolism of gymnosomatous pteropods in waters of the western Antarctic Peninsula shelf during austral fall

Suprenand¹,

Ombres²,

Torres³

2015

Mar. Ecol. Prog. Ser.

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Two species of Southern Ocean gymnosomatous pteropods with dissimilar distributional ranges were collected from western Antarctic Peninsula (WAP) shelf waters in the vicinity of Anvers, Lavoisier, Adelaide and Charcot Islands from March to April 2010 and between 0 and 500 m. The sub-Antarctic gymnosome species, Spongiobranchaea australis, typically occupies regions north of the Polar Front, whereas the true Antarctic gymnosome species, Clione antarctica, inhabits colder waters and higher latitudes. Oxygen consumption rates, ammonia excretion rates, proximate body compositions and the activities of 3 metabolic enzymes-lactate dehydrogenase, malate dehydrogenase, and citrate synthase (CS)-were determined in both gymnosome species. Oxygen consumption rates of S. australis and C. antarctica were found to be similar; however, the mean ratio of oxygen consumed to ammonia excreted (O:N, 61.26 ± 18.68:1) indicated that S. australis was oxidizing primarily lipids while C. antarctica was oxidizing a mixture of proteins and lipids (26.41 ± 14.82:1). Proximate body compositions based on percent protein, percent lipid, and carbon to nitrogen ratios, suggested larger lipid storage in C. antarctica (~5%) than in S. australis (~3%). CS activities among gymnosomes were dissimilar, and comparisons of enzyme activities were made to other Antarctic organisms. Observed differences in S. australis' physiological indicators may be related to prolonged starvation, whereas C. antarctica appears ready to survive overwintering in Antarctica. Water mass advection from the Antarctic Circumpolar Current is thought to be transporting S. australis onto the WAP shelf, and away from its typical sub-Antarctic habitat.

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“…Recently, some research groups introduced liquid crystalline (LC) polymers to TPEs to obtain liquid crystalline thermoplastic elastomers (LCTPEs). , The introduction of liquid crystallinity can help improve the high service temperatures and mechanical properities of TPEs. Sanger et al attached LC units onto the soft block of SBS. − They investigated the relationships among liquid crystallinity, microphase-separated structures, and mechanical properties of the resulting LCTPEs.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of New Liquid Crystalline Thermoplastic Elastomers Containing Mesogen-Jacketed Liquid Crystalline Polymers

Zhang

Shen

et al. 2016

Macromolecules

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In order to improve the high-temperature performance of thermoplastic elastomers (TPEs), we designed and synthesized a new kind of ABA triblock copolymer containing a mesogen-jacketed liquid crystalline polymer (MJLCP), poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene} (PMPCS), as the hard blocks and polybutadiene (PB) as the soft block. The triblock copolymer, PMPCS-b-PB-b-PMPCS (M-B-M), was synthesized by ring-opening metathesis polymerization in the presence of a chain transfer agent and atom transfer radical polymerization. The glass transition temperature (T g ) of the PMPCS hard block is 110−118 °C in the triblock copolymers. In addition, the liquid crystalline (LC) phase of PMPCS is stable before thermal decomposition. All the triblock copolymers form lamellar microphase-separated structures, as demonstrated by small-angle X-ray scattering and transmission electron microscopy results. The triblock copolymer (M-B-M-55) with a mass fraction of 55% of PMPCS exhibits typical properties of an LC thermoplastic elastomer (LCTPE). The maximum elongation at break and the tensile strength of M-B-M-55 are 736% and 10.6 MPa, respectively, and the stretching strength at 300% is 6.9 MPa. Above the T g of PMPCS, the LC phase of PMPCS provides new physical cross-linking points in the LCTPEs, and the triblock copolymer M-B-M-55 still shows a relatively high modulus.

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Physically crosslinked elastomers prepared from oligomeric polyolefins with mesogenic units

Cited by 9 publications

References 18 publications

ABA Type Triblock Copolymer Based on Mesogen-Jacketed Liquid Crystalline Polymer: Design, Synthesis, and Potential as Thermoplastic Elastomer

ABA Type Triblock Copolymer Based on Mesogen-Jacketed Liquid Crystalline Polymer: Design, Synthesis, and Potential as Thermoplastic Elastomer

Metabolism of gymnosomatous pteropods in waters of the western Antarctic Peninsula shelf during austral fall

Synthesis and Characterization of New Liquid Crystalline Thermoplastic Elastomers Containing Mesogen-Jacketed Liquid Crystalline Polymers

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