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Journal ArticleDOI

Synthesis of triblock copolymers?(polyA-poly butadiene-polyA)?via metathesis polymerization

01 Oct 1998-Journal of Polymer Science Part A (Wiley)-Vol. 36, Iss: 14, pp 2601-2610

Abstract: A series of triblock copolymers of the type A-B-A were synthesized using tungsten chloride-anchored hydroxyl-terminated polybutadiene (HTPBD) catalyst. Monomers like phenylacetylene (PA), norbornene (NBE), cyclooctadiene (COD), and cyclopentene (CP) were polymerized via metathesis pathway using this catalyst. The efficiency of this anchored catalyst in producing A-B-A triblock copolymers was explored and compared under the same experimental conditions like solvent system and reaction temperature. This anchored catalyst upon reaction with PA produced polyPA-block-polyBD-block-polyPA in high yield and with low polydispersity (pdi) compared to HTPBD. The formation of the triblock copolymers by this method was evinced by NMR, TGA, and GPC data as well as by delinking and inverse addition studies. All the cycloalkenes polymerized via ring-opening metathesis polymerization (ROMP) with the catalyst and yielded triblock copolymers. The mode of synthesis of triblocks could be construed as switching the mechanism of polymerization from radical to olefin metathesis.
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Journal ArticleDOI
Zhiyi Yang1Institutions (1)
28 Feb 2008-Macromolecules
Abstract: Linear dynamic viscoelasticity of miscible polymer blends with hydrogen bonding has been investigated. The polymer blend systems investigated are (1) blends of poly(vinylphenol) (PVPh) and poly(vinyl acetate) (PVAc), (2) blends of PVPh and poly(vinyl methyl ether) (PVME), (3) blends of PVPh and poly(2-vinylpyridine) (P2VP), and (4) blends of PVPh and poly(4-vinylpyridine) (P4VP). Fourier transform infrared (FTIR) spectroscopy was employed to find that both the intraassociation (self-association) of the phenolic −OH groups in PVPh and interassociation (intermolecular interactions) between the constituent components in each blend system have profound influence on the frequency dependence of dynamic moduli in the terminal region of the PVPh-based miscible blend systems. It has been found further that time−temperature superposition (TTS) is applicable to all four PVPh-based miscible blend systems forming hydrogen bonds, including the PVPh/PVME blends having the difference in component glass transition tempera...

70 citations

Cites methods from "Synthesis of triblock copolymers?(p..."

  • ...Sundararajan et al.171 used a macro-difunctional initiator for metathesis polymerization to obtain triblock copolymers....


  • ...Sundararajan et al.(171) used a macro-difunctional initiator for metathesis polymerization to obtain triblock copolymers....


Journal ArticleDOI
02 Jul 2004-Macromolecules
Abstract: High molecular weight telechelic [dicyano- and dichloro-] polybutadienes (TPBs) have been synthesized via ring-opening metathesis (ROM) polymerization of 1,5-cyclooctadiene (COD) in the presence of the difunctional chain transfer agents (CTAs), 1,4-dicyano- or 1,4-dichloro-2-butene. To achieve high molecular weights, it was critical that the COD monomer contained very low levels of the contaminating, isomeric 4-vinylcyclohexene (VCH), since the latter serves as a competing CTA. An NMR method for determining the level of VCH was developed as well as “reactive purification” strategy in which the VCH was selectively depleted by its (faster) hydroboration. A “two-stage” protocol for preparation of the TPBs was developed wherein a small portion of the eventual charge of COD and the entire quantity of the CTA were first copolymerized to produce telechelic oligomeric butadiene (TOB) of low viscosity. After all of the CTA had been consumed, the remaining COD was charged. This protocol allowed for better MW contro...

51 citations

Journal ArticleDOI
Peng Liu1, Chunjin Ai2, Chunjin Ai1Institutions (2)
Abstract: The olefin metathesis reaction has showed promising application in rubber chemistry and industry in the last decades for the production of specialty rubbers (polyene rubbers, low-molecular-weight telechelic oligomers, hydrogenated diene-based rubbers, liquid rubbers, and other functional rubbers) and characterization and recycling of rubber products (waste tires or others) via ring-opening metathesis polymerization (ROMP) or the cross-metathesis (CM) degradation technique. Here, recent advances in both molecular modeling and experimental investigations of the olefin metathesis reaction in rubber chemistry and industry are reviewed, and the challenges of future applications are also prospected.

20 citations

Book ChapterDOI
E. Maréchal1Institutions (1)
09 Feb 2006-

11 citations

01 Jan 2010-
Abstract: Much interest on the thermoplastic elastomers (TPEs) has recently been attracted in commercial fields as well as scientific and applied researches. The TPEs have their own characteristic area especially in relation with block copolymers as well as many other polymeric materials, since they show interesting features displayed by the conventional vulcanized rubber, and at the same time, by the thermoplastics. In addition, they are characterized by a set of interesting properties inherent to block and graft copolymers, variety of blends and vulcanized materials. The importance of TPE as organic materials can be evaluated by the number of published reports (papers, patents, technical reports, etc). The input of the concept 'thermoplastic elastomer' to SciFinderScholar yields 18,508 results between 1939 and July 10, 2010, and the number increased exponentially after the mid of 1990. For the suitable introduction of the TPE, historic, scientific, technical and commercial considerations should be taken into account. This review article starts with a brief discussion on historical considerations, followed by a introduction of the main preparations and analytical techniques utilized in chemical, structural, and morphological studies. The properties, processing tools, the position among organic materials, and applications of TPEs are also briefly reviewed. Finally, the most probable trends of their future development are discussed in a short final remarks.

7 citations

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