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Predecessor
Volume 76, Issue 8
Displaying 1-10 of 10 articles from this issue
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[in Japanese], [in Japanese]2003 Volume 76 Issue 8 Pages 273
Published: 2003
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSDownload PDF (179K) -
Katsuhiko TAKENAKA2003 Volume 76 Issue 8 Pages 274-280
Published: 2003
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSThe characteristics of various types of living polymerization such as free-radical, cationic, anionic, coordination and ring-opening metathesis polymerizations and the formation of block copolymers by sequential monomer addition method were reviewed. In the case of free-radical polymerization, three individual methods such as nitroxide-mediated polymerization (NMP), atom-transfer radical polymerization (ATRP) and reversible addition fragmentation chain-transfer (RAFT) processes were compared concerning with the reaction condition and the kinds of applicable monomers. For anionic processes, principle mechanisms of immortal polymerizations and group transfer polymerization (GTP) as well as classical living anionic polymerization were reviewed. The unique feature of ring-opening metathesis polymerization (ROMP) was also described.View full abstractDownload PDF (1222K) -
Kimio IMAIZUMI2003 Volume 76 Issue 8 Pages 281-284
Published: 2003
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSTo date, various kinds of high performance polymer materials have been used in the IT industry, or bio and biomedical industry. Such a magnified spreading of polymer materials is due to the nano-technologies supported by the recent well-defined polymer syntheses or molding technologies. To give a typical example, block copolymers consisting of two or more chemically different monomer units connected at the chain ends have various types of microphase separated structure depending on their components and molecular weights. In this report, we focus on the higher-order structure of the novel thermoplastic elastomers, 1, 3-cyclohexadiene (CHD) / butadiene block copolymers, that is the most important factor for affecting polymer properties.View full abstractDownload PDF (856K) -
Mitsuo SAWAMOTO, Masami KAMIGAITO, Tsuyoshi ANDO2003 Volume 76 Issue 8 Pages 285-288
Published: 2003
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSThis article presents a concise account for the synthesis of block copolymers by living cationic polymerization that are potential thermoplastic elastomers. Typical examples include ABA-block polymers of isobutylene or vinyl ethers (as B) for soft/mid segments and styrene derivatives (as A) for hard/end segments. The synthetic methodologies include consecutive cationic polymerization with bifunctional initiators and combinations of living cationic and metal-catalyzed living radical polymerizations. Brief dicsussion is also given for their elastic and mechanical properties.View full abstractDownload PDF (680K) -
Takeshi FUKUDA, Atsushi GOTO2003 Volume 76 Issue 8 Pages 289-293
Published: 2003
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSLiving radical polymerization (LRP) is distinguished from conventional radical polymerization by its including a reversible deactivation process of the growing radical. It has several different branches depending on the mechanism of reversible deactivation. This work gives a brief survey of recent development in the theory, kinetics, and techniques of LRP, emphasizing the importance of mechanistic understandings for a successful application of LRP. It then illustrates applications and possibility of LRP for the synthesis of new block copolymers including thermoplastic elastomers.View full abstractDownload PDF (981K) -
Masato KIJIMA2003 Volume 76 Issue 8 Pages 294-298
Published: 2003
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSWe feature of polymers obtained by metallocene catalysts and development of new elastomeric polyolefins are descrived here. Especially, ethylene-norbornene copolymer as ethylene based elastomer, and new elastomeric polypropylene as propylene based one are introduced previous report. That new polypropylene is prepared by specific control technology with metallocene catalysts. I assume that ethylene based elastomer will have been main material in elastomeric polyolefin market in the future. However, I think that new propylene based elastomer has high potential.View full abstractDownload PDF (1004K) -
Yasuhiro NISHIHARA2003 Volume 76 Issue 8 Pages 299-303
Published: 2003
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSThermoplastic polyester elastomers can be classified into two types depending on the soft segment in the copolymer that gives it resilience. Polyester-polyether-type is a block copolymer consisting of PBT as the hard segment and PTMG as the soft one. It covers general-purpose grades, being designed to have flexibility, heat resistance, cold resistance, chemical resistance, processability and more in the best balanced proportion. Polyester-polyester-type consists of PBT as the hard segment and PCL as the soft one, has physical properties comparable to Polyester-polyether-type, and has unequal heat aging and light resistance. In recent years, high durability special polyester-polyether-type grades with excellent fatigue endurance and resistance to grease have been developed and applied to CVJ boots. Also new generation TPEE consisting of PBN as the hard segment has excellent resistance to hydrolysis, chemicals, oil, high temperature, abrasion and low expansion coefficient. These will stretch the limit of TPEE.View full abstractDownload PDF (774K) -
Tsutomu YOKOZAWA, Akihiro YOKOYAMA2003 Volume 76 Issue 8 Pages 304-309
Published: 2003
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSThermoplastic elastomers containing condensation polymers have been produced as generally multiblock copolymers, not di- or triblock copolymers, because polycondensation proceeds in a step-growth polymerization manner, not in a chain-growth polymerization manner like living polymerization. We have recently developed novel polycondensation that propagates from an initiator in a chain-growth manner (chain-growth polycondensation) to yield condensation polymers with defined molecular weights and low polydispersities. This polycondensation method will open to an access to new thermoplastic elastomers made of triblock and star block copolymers containing well-defined condensation polymers as block units. Herein we describe the polycondensation for well-defined aromatic polyamides as an example of chain-growth polycondensation and the synthesis of block copolymers and star block copolymers, which consist of condensation polymers and general polymers such as polystylene and poly(ethylene glycol). Furthermore, its application to the synthesis of novel thermoplastic elastomers is also discussed.View full abstractDownload PDF (1021K) -
Junji KOJINA2003 Volume 76 Issue 8 Pages 310-315
Published: 2003
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSThermoplastic elastomers (TPE) produced by dynamic vulcanization which is one of the reactive processings are generally called thermoplastic vulcanizates (TPV). TPV are polymer alloys composed of themoplastics and elastomers.
The growth of demand for TPV is very high, so TPV becomes one of the majority of TPE. The manufacturing methods have been improved in order to make the cost/performance of TPV better. At first Internal mixers like Banbury mixers were used for dynamic vulcanization and recently the twin screw extruders seems to be used mainly. The twin screw extruders are more suitable for continuous production than the Banbury mixer. The performance of TPV is controlled by three main factors, the characteristic of the continuous phase polymer (thermoplastics), that of the dispersed phase polymer (elastomrers vulcanized dynamically), and the morphology. The particle size of dispersed phase is important for the mechanical properties, especially tensile strength and compression set. The smaller the dispersion size is, the better the performance is. The dispersion size is controlled by the operating condition of mixing machines.
The olefinic types of TPV have been mainly produced, but now some products except the olefinic TPV are developed commercially. In the future new types of TPV will be developed by manufacturing methods improved furthermore.View full abstractDownload PDF (1220K) -
[in Japanese], [in Japanese]2003 Volume 76 Issue 8 Pages 316-317
Published: 2003
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSDownload PDF (381K)
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