A Volume-Corrected Kratky Model and the Influence of the Shape of the Orientation Distribution Function on the Molecular Orientation in PPV and Its Precursor

Dermaut, Wim; Kerkhof, Tom Van den; Goderis, Bart; Mertens, R.; Dolbnya, Igor P.; Veken, B. Van der; Blockhuys, Frank; Geise, H.J.

doi:10.1021/ma034404y

Cited by 5 publications

(4 citation statements)

References 17 publications

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“…The relevant parameters are shown in Table S2. In addition, the Hermans orientation parameter f is introduced to quantitatively analyze the BNNS-OH orientation, which is calculated by …”

Section: Resultsmentioning

confidence: 99%

Biomimetic Nacreous Composite Films toward Multipurpose Application Structured by Aramid Nanofibers and Edge-Hydroxylated Boron Nitride Nanosheets

Zhao

Wei

Ren

et al. 2022

Ind. Eng. Chem. Res.

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High-performance dielectric film is one of the most promising materials for comprehensive applications ranging from high-voltage electrical equipment to high-power electronic devices. We here report the fabrication of biomimetic nacreous multifunctional composite films by self-assembling nanoscale building blocks of one-dimensional (1D) aramid nanofibers (ANFs) and two-dimensional (2D) edge-hydroxylated boron nitride nanosheets (BNNS-OH). Synchronously, poly(vinyl alcohol) was introduced as soft glue to improve the interfacial interaction between ANFs and BNNS-OH by building a three-dimensional (3D) hydrogen-bond network. Attributing to the well-designed nanostructure and favorable interfacial hydrogen bonding, the resultant composite films exhibited a ultrastrong tensile strength (∼329.6 MPa), a high thermal conductivity (16.03 W m −1 K −1 ), outstanding dielectric properties, superior thermostability, and long life. Moreover, these synergistic properties of composite films were tunable by changing the contents of BNNS-OH to accommodate the requirements of multipurpose applications in the development of advanced insulation systems and thermal management materials.

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“…The relevant parameters are shown in Table S2. In addition, the Hermans orientation parameter f is introduced to quantitatively analyze the BNNS-OH orientation, which is calculated by …”

Section: Resultsmentioning

confidence: 99%

Biomimetic Nacreous Composite Films toward Multipurpose Application Structured by Aramid Nanofibers and Edge-Hydroxylated Boron Nitride Nanosheets

Zhao

Wei

Ren

et al. 2022

Ind. Eng. Chem. Res.

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“…[19,24] The most popular is that of Holmes and Barrington Leigh (HBL), which, under the assumption of small misalignment, were able to calculate the F function, obtaining…”

Section: Profile Functions In Diffraction Patterns 585mentioning

confidence: 99%

“…[26] The integral representation of the modified Bessel functions of the second type of order zero used in Ref. 19 …”

Section: Profile Functions In Diffraction Patterns 585mentioning

confidence: 99%

“…This approach was introduced by Holmes and Barrington Leigh (HBL), who considered the case of small misalignment of identical particles, assumed a Gaussian ODF, and computed the profile function for the diffracted intensity. [18] Although the Gaussian assumption for the ODF can be questionable in view of specialized ODF for stretched fibers, direct experimental indications in favor of this conjecture have been given in a particular case [19] and the reasonable results obtained in diffraction analyses in terms of this assumption [20,21] are in themselves an indirect indication that in many cases the true ODF should not differ to much from a Gaussian one. The HBL formula is rather cumbersome for practical fitting pocedures and was not specialized for the case of polycrystalline fibers.…”

Section: Introductionmentioning

confidence: 99%

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Profile Functions in Diffraction Patterns of Semicrystalline Fibers with Gaussian Misalignment

Fedullo

Antinucci

Immirzi

et al. 2005

Journal of Macromolecular Science, Part B

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The profile functions expected in diffraction patterns of axially oriented semicrystalline fibers are discussed. Attention is focused on a Gaussian distribution of the crystallite unique axes. The limits of applicability of known approximations to the computationally demanding theoretical profile function have been found and a simple correction has been proposed enabling the computation of the profile functions near the meridian and on the meridian itself. Test calculations show that this correction leads to better agreement with the theoretical profile functions

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Reversible Addition−Fragmentation Chain Transfer Polymerization of N-Isopropylacrylamide: A Comparison between a Conventional and a Fast Initiator

Bouchékif

Narain

2007

J. Phys. Chem. B

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The reversible addition-fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide (NIPAM) was studied to determine the reasons for deviation of experimental molecular weights to lower molecular weight at high monomer conversion when S-1-dodecyl-S-(alpha,alpha'-dimethyl-alpha' '-acetic acid)trithiocarbonate (CTAm) and S,S-bis(alpha,alpha'-dimethyl-alpha' '-acetic acid)trithiocarbonate (CTAd) were used as RAFT agents at 65 degrees C. For this purpose, experiments were performed in N,N'-dimethylformamide (DMF) at the NIPAM/CTA ratio of 200 with initiators capable of yielding fast and slow initiation, respectively by photochemical and thermal process, either at ambient temperature or at 65 degrees C. When the polymerization of NIPAM was conducted under these conditions with Irgacure-2959 (IRGC) as photoinitiator, a continuing supply of primary radicals by incremental initiator addition was required to achieve reasonably high conversion. This effect was also apparent by the loss of linearity of the first-order kinetic plot with a conventional initiator (4,4-azobis(4-cyanovaleric acid) (ACVA) as azo-initiator, 10h (t1/2) decomposition at 65 degrees C) indicating that steady-state concentration of the macroradical decreases significantly with the initiator consumption. Nevertheless, polymers with predictable number-average molecular weight Mn (i.e., based on [monomer]/([CTA] + [initiator]) ratio) and narrow polydispersities were obtained (PDIs << 1.2) with CTAm indicating that the process of chain growth was controlled. When CTAd was used, instead of CTAm, the polymers obtained were characterized by a larger polydispersity (1.2 < PDIs < 1.3). The so-called "living steady-state concentration" in chain equilibration together with the linear dependence of Mn vs conversion was observed only when the 200/1 NIPAM/CTA mixture in DMF was subjected to a permanent photoirradiation at 65 degrees C. With ACVA, the deviation of the experimentally measured molecular weights at high conversion was accounted for by the simultaneous self-initiated polymerization of NIPAM with the controlled process in the presence of CTA at 65 degrees C. Similar drift from the linear dependence Mn vs conversion was also observed at 65 degrees C when a significant number of low molecular weight polymer chains were generated intentionally by photodecomposition of IRGC.

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A Volume-Corrected Kratky Model and the Influence of the Shape of the Orientation Distribution Function on the Molecular Orientation in PPV and Its Precursor

Cited by 5 publications

References 17 publications

Biomimetic Nacreous Composite Films toward Multipurpose Application Structured by Aramid Nanofibers and Edge-Hydroxylated Boron Nitride Nanosheets

Biomimetic Nacreous Composite Films toward Multipurpose Application Structured by Aramid Nanofibers and Edge-Hydroxylated Boron Nitride Nanosheets

Profile Functions in Diffraction Patterns of Semicrystalline Fibers with Gaussian Misalignment

Reversible Addition−Fragmentation Chain Transfer Polymerization of N-Isopropylacrylamide: A Comparison between a Conventional and a Fast Initiator

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