Polytetrahydrofuran

Dreyfuss, P.; Dreyfuss, M. P.

doi:10.1007/bfb0051094

Cited by 135 publications

(32 citation statements)

References 47 publications

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“…As no data have been reported about the solubility parameters of PA1012, the group contribution method of Van Krevelen was applied to estimate the solubility parameter . The solubility parameters are ~23.24 and 17.39 (J/cm 3 ) 0.5 for PA1012 and PTMO, respectively . Based on these values, the parameter χ of PA1012‐ mb ‐PTMO copolymers can be approximated to 1.38, and the corresponding χN value (at room temperature) falls into the range of 11‐27, which is shown in Table S1 (Supporting Information).…”

Section: Resultsmentioning

confidence: 94%

“…Based on the unit cell parameters for the hydrogen‐bonded sheet progressively stacked PA1012 α‐phase, the density of amorphous and crystalline regions within PA1012 is calculated to be 1.00 and 1.13 g/cm 3 , respectively . Although the corresponding density for PTMO is 0.99 and 1.06 g/cm 3 . These values are only approximated, as the amorphous phases are not pure but a mixture of amorphous chains in the PA1012‐rich and PTMO‐rich phases.…”

Section: Resultsmentioning

confidence: 99%

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Influence of soft block crystallization on microstructural variation of double crystalline poly(ether‐ mb ‐amide) multiblock copolymers

Cao

Zhu

Wang

et al. 2018

Polymer Crystallization

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This work reports the crystallization behavior of a series of poly(ether‐mb‐amide) multiblock copolymer (PEAc) samples, composed of long‐chain carbon polyamide 1012 (PA1012) as hard segments and poly(tetramethylene oxide) (PTMO) as soft segments. Rheological and dynamic mechanical results showed that PA1012‐mb‐PTMO multiblock copolymers are microphase segregated in the both melt and solid states, forming two partially miscible phases with distinct crystallization and glass‐transition temperatures that depend on composition. The copolymers are probably in the weak segregation limit, as the PA1012‐rich phase can break out and form spherulitic templates during cooling from the melt. For the PA1012‐mb‐PTMO copolymers with long PTMO segments, it was found that the crystallization of the PTMO‐rich phase induced a variation in the long period as temperature decreased. This effect was related to the content of PTMO segments. At room temperature, only the PA1012‐rich phase crystallized, whereas PTM‐ rich phase remained amorphous within the interlamellar regions of the PA1012 spherulitic templates. Upon further cooling, the PTMO‐rich phase crystallized forming crystalline lamellae located in between the adjacent PA1012 lamellae, forming double crystalline spherulites. Based on the research results, a schematic model was proposed to describe the multistage crystallization behavior of PA1012‐mb‐PTMO copolymers.

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Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Influence of soft block crystallization on microstructural variation of double crystalline poly(ether‐ mb ‐amide) multiblock copolymers

Cao

Zhu

Wang

et al. 2018

Polymer Crystallization

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“…Figure 2(a) is an infrared spectrum of the material formed during this oxidation process. It compares well to the infrared spectrum of polyTHF (12).…”

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confidence: 61%

Polythiophene/PolyTHF: A Multicomponent Electrically Conducting Polymer

Druy¹

1986

J. Electrochem. Soc.

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Electrically conducting polymers have been plagued in the past by problems associated with environmental stability and/or poor mechanical properties. Polyacetylene, the prototype conducting polymer, was successfully blended with elastomers (1) and thermoplastic elastomers (2). As a result its mechanical properties were dramatically improved. Blending, however, had no major impact on stability (1). Soluble processible conducting polymer precursors such as polyphenylene and polyphenylene sulfide have been doped in solution and conducting films of these materials could be cast from the solution (3). Unfortunately, once doped, polyphenylene and polyphenylene sulfide are quite reactive in air (4, 5).Polyheterocycles such as polythiophene and polypyrrole are polymers which have exhibited dramatic improvements in oxidative stability (6). Recent work by several investigators has enhanced the mechanical properties of polypyrrole by forming composites with polyvinyl alcohol and polyvinyl chloride (7).Polythiophene, however, has rather poor mechanical properties. In fact it is very difficult to synthesize polythiophene as a free-standing film (>10 microns thick). Most attempts to electrochemically synthesize polythiophene result in intractable powders which are deposited on the surface of an electrode (8,9). Only by keeping the current density at 10 tLAYcm 2 is it possible to peel off a fragile free-standing film (9). Since the conductivity of polythiophene is rather stable in air, attempts to improve its mechanical properties and processibility are warranted. Furthermore our research is aimed at obtaining structural modification and control of the morphology of polymers via electrochemical means. This communication describes a successful electrochemical approach to the improvement of the mechanical properties and processibility of polythiophene. Recent work by Frommer et al. suggests that polythiophene can be chemically polymerized in solution and conducting films can be cast (10). In another laboratory, free-standing films of polythiophene were grown electrochemically using large applied potentials (>10V) (11). Because of these high potentials, other reactions such as ring opening may occur and thus the material may contain species other than polythiophene.Experimental A three compartment electrochemical cell was used for the electrochemical synthesis of a polythiophene/ polyTHF multicomponent system. Figure 1 shows this cell. A Ag/Ag + reference electrode (+0.3V vs. SCE) was used to monitor the working electrode potential during the galvanostatic synthetic process. The working electrode was a 4 cm • 2.5 cm platinum working electrode, and a nickel mesh counterelectrode was used. The cell was filled with 50 ml of a 1M lithium perchlorate in tetrahydrofuran solution. The lithium perchlorate (G. F. Smith Company) had been previously dried at 110~ in dynamic vacuum for 36h, and then melted and allowed to cool under dynamic vacuum. The tetrahydrofuran (Fisher HPLC) was refluxed over lithium aluminum hydride, collected, and tra...

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“…The redistribution of molecular weight observed in certain THF polymerizations has been explained this way. 4 Triethyl orthoformate has been used as a chain transfer reagent to deliberately control polymer molecular weight in T H F polymerizations.…”

Section: Oxonium Ion Polymerizationmentioning

confidence: 99%

Some Comments on the Mechanisms of Epoxide Polymerization*

Kuntz¹

1971

Trans NY Acad Sci

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Polytetrahydrofuran

Cited by 135 publications

References 47 publications

Influence of soft block crystallization on microstructural variation of double crystalline poly(ether‐ mb ‐amide) multiblock copolymers

Influence of soft block crystallization on microstructural variation of double crystalline poly(ether‐ mb ‐amide) multiblock copolymers

Polythiophene/PolyTHF: A Multicomponent Electrically Conducting Polymer

Some Comments on the Mechanisms of Epoxide Polymerization*

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