Structure of solution-grown trans-1,4-polyisoprene crystals: 1. Determination of stem length and fold surface structure by ozonolysis-g.p.c. measurement

Block copolymer of trans‐polyisoprene and urethane segment: Crystallization behavior and morphology

“…As observed in this figure, the crystallinity of TPI decreases with the content of the hard segment increasing. There have been many studies that have elucidated comprehensively the crystalline properties of TPI;5–8, 20, 22 polymers of modified TPI were not involved, in contrast. Our studies find that TPI block in the copolymer is still capable of crystallizing but displays the crystallization behaviors distinguishing it from that of TPI.…”

“…It is worthwhile to mention that many studies concerning solution crystallizations of polyolefins have found that the polymer crystals generated almost appear in single form 8, 20. Although TPI usually crystallizes in two forms (HM and LM), the polymer is ready to crystallize into the HM crystals during the solution crystallization at −20°C 20. An interesting question arising is whether the urethane segment introduced affects the crystal forms of TPI.…”

“…Their difference in solubility may lead to a complete two‐phase separation in the solution, where each moiety manages to behave with its own properties during the crystallization. It is worthwhile to mention that many studies concerning solution crystallizations of polyolefins have found that the polymer crystals generated almost appear in single form 8, 20. Although TPI usually crystallizes in two forms (HM and LM), the polymer is ready to crystallize into the HM crystals during the solution crystallization at −20°C 20.…”

Synthetic Uniform Polymers and Their Use for Understanding Fundamental Problems in Polymer Chemistry

“…A topochemical approach toward almost uniform polymers has already been realized by Tanaka and his co-workers on diene polymers. [74,75] That is, ozonolysis of chain-folded lamellar crystals of cis-and trans-1,4-polyisoprenes and 1,4-polybutadienes gave the oligomers, the molecular weights of which most closely corresponded to the lamellar thickness, as the reaction occurred selectively on the fold parts of the lamellar surface. The resulting oligomers had a very narrow MWD and could be easily fractionated into uniform oligomers by SEC.…”

“…The resulting oligomers had a very narrow MWD and could be easily fractionated into uniform oligomers by SEC. [74,75] The template-controlled oligomerization of MMA was reported as an experimental approach that utilizes a large rigid spacer template to fix the positions of an initiating functionality and a terminating one (Scheme 11). [76] In this oligomerization reaction, propagation is expected to occur only within the initiator-terminator gap, and molecular weight of the resultant oligomer should depend solely on the template size.…”