Results 161 to 170 of about 11,202 (203)

Polyisoprene

Rubber Chemistry and Technology, 1979
Abstract From the time, more than, a century ago, that isoprene was isolated by pyrolysis of natural rubber, scientists around the world have attempted to reverse the process, namely, to prepare rubber from isoprene. Bouchardat, in 1879, reported what may have been the first preparation of a synthetic rubbery material.
E. Schoenberg, H. A. Marsh, S. J. Walters, W. M. Saltman   +3 more
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Nanoporous Crosslinked Polyisoprene from Polyisoprene?Polydimethylsiloxane Block Copolymer

Polymer Bulletin, 2004
The polyisoprene block of a polyisoprene-polydimethylsiloxane (PI-PDMS) diblock copolymer with 0.68 volume fraction of PI was tightly crosslinked with dicumylperoxide. The PDMS part of the obtained glassy material was subsequently quantitatively etched with anhydrous hydrogen fluoride or tetrabutylammonium- fluoride, in this way obtaining a nanoporous ...
Michael S. Hansen, Martin E. Vigild, Rolf H. Berg, Sokol Ndoni   +3 more
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Sequence distribution of polyisoprenes

Polymer, 1976
Abstract Isoprene can be polymerized into four types of isomeric structures; cis-1,4, trans-1,4, 3,4, and 1,2, depending on catalysts and polymerization conditions. So far, the difference of mechanical and thermal properties among polyisoprenes has been discussed chiefly on the basis of amounts of these isomeric structures. However, it is quite
Y. Tanaka, H. Sato
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Diffusion of linear polyisoprene molecules into polyisoprene networks

Journal of Polymer Science Part B: Polymer Physics, 1989
AbstractDiffusion and equilibrium absorption of polyisoprene liquids into crosslinked samples of cis‐polyisoprene (natural rubber) have been studied by direct observation of volume swelling. Natural rubber was crosslinked in the form of fine threads, about 40 ± 20 μm in diameter, using a gaseous reaction with SO2 and H2S (the Peachey process).
A. N. Gent, S. Y. Kaang
openaire   +1 more source

Polyisoprene modified polystyrene

Polymer, 1978
Abstract Polyisoprenes have been used to prepare modified polystyrenes in an attempt to improve impact strength. It has been determined that polyisoprene reinforces polystyrene by the formation of complex rubber phase particles, similar to those in commercial polybutadiene reinforced polystyrenes. These particles, however, are subject to breakdown by
H. Keskkula, S.G. Turley
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Anticoagulant mechanism of sulfonated polyisoprenes

Biomaterials, 2002
The influence of sulfonated polyisoprene (SPIP) on coagulation factors and human blood cells was investigated to elucidate and compare its anticoagulant mechanism with that of heparin. While the number of red cells was unaffected, the number of platelets decreased dramatically in the presence of SPIP due to aggregation.
Yasushi, Tamada, Mitsuhiro, Murata, Toshio, Hayashi, Kohei, Goto   +3 more
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Anticoagulant effects of sulphonated polyisoprenes

Biomaterials, 1998
Sulphonated polyisoprenes (SPIPs) having various molecular weights and sulphonate group contents were synthesized and their anticoagulant activities investigated. Prolongation of blood clotting time, prothrombin time and activated partial thromboplastin time were observed in the presence of SPIPs. The anticoagulant activity in blood was affected mainly
Y, Tamada, M, Murata, K, Makino, Y, Yoshida, T, Yoshida, T, Hayashi   +5 more
openaire   +2 more sources

Ozonolysis of 1,4-cis-polyisoprene and 1,4-trans-polyisoprene in solution

Polymer Degradation and Stability, 2000
The reaction of ozone with 1,4-cis-polyisoprene (E-IR) and 1,4-trans-polyisoprene (Z-IR) has been investigated in CCl4 solution. By means of IR-spectroscopy and 1H-NMR spectroscopy it was established that the basic ozonolysis products of both elastomers are ozonides, ketones, and aldehydes.
M.P Anachkov, S.K Rakovski, R.V Stefanova   +2 more
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Infrared Examination of Various Polyisoprenes

Rubber Chemistry and Technology, 1953
Abstract It is well known that, in general, the laboratory polymerization of diene monomers leads to materials which are intramolecular mixtures of various types of addition products. Thus, synthetic polyisoprene has been shown to contain chemical groupings arising from 1,2, 3,4, and 1,4 addition of the isoprene units.
W. S. Richardson, A. Sacher
openaire   +1 more source

Polymorphic crystallization behaviors in cis-1,4-polyisoprene/trans-1,4-polyisoprene blends

Polymer, 2015
Abstract Polymorphic crystallization behaviors in amorphous/crystalline polymer blends of cis-1,4-polyisoprene/trans-1,4-polyisoprene (CPI/TPI) have been not fully understood so far. In this work, we investigated the effects of CPI content and crystallization temperature on crystal nucleation, spherulite growth rate and crystallinity of α- and β-TPI ...
Kuncheng Yao, Huarong Nie, Yongri Liang, Dong Qiu, Aihua He   +4 more
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