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Acyclic polymers containing a large number of isoprene subunits, usually unsaturated.
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The elastomer compounds are compositions based on at least one diene elastomer selected from the group of polybutadienes (BRs), synthetic polyisoprenes (IRs), natural rubber (NR), isoprene copolymers, butadiene copolymers with the exception of butadiene-nitrile copolymers (NBRs), apart from diene elastomers bearing carboxyl functions, and mixtures of these diene elastomers.
The first extensive IR spectroscopic studies of synthetic polyisoprenes were undertaken by Binder, Cornell, and Koenig.
As it is well known, polyisoprene (PIp) is one kind of important rubbers, and there are four kinds of microstructure in its molecular chain which are cis-1,4-, trans-1,4-, 1,2-, and 3,4-polyisoprene.
Increasing the catalyst level and Al/Fe ratio from their low to high designed values will decrease the average DSV by 2.0 and 1.3, respectively; therefore, both variables should be maintained at high levels in order to produce low DSV polyisoprenes.
The goal of preparing synthetic polyisoprene as a potential replacement for natural rubber was vigorously pursued in the early 1950s and 1960s by several laboratories in the United States.
Key statement: Branched synthetic polyisoprenes are described having a macrostructure and a microstructure very similar to those of natural rubber.
Cotan [delta] [??] 0.3761 [[eta].sub.inh] + 0.15,: (i) where cotan [delta] is the cotangent of the loss angle of a sample of said polyisoprene, measured at 130[degrees]C.
(47) Structural development of polyisoprenes during uniaxial stretching by in-situ synchrotron WAXD and SAXS.
11), and defect structures in polyisoprenes (head-to-head and tail-to-tail structures) were studied by Hackathom and Brock in 1971 (ref.
Natural rubber is polyisoprene, and when pyrolyzed yields large amounts of the monomer (isoprene), the dimer (dipentene) and higher oligomers.
PBD-8 contains 8% 1,2 units) and for the polyisoprenes indicates the molecular weight (i.e.
Blends containing very high 1,2, contents had extremely broad Tgs much closer to the polyisoprene Tg.