Free Volume of Montmorillonite/Styrene‐Butadiene Rubber Nanocomposites Estimated by Positron Annihilation Lifetime Spectroscopy

Wang, Yiqing; Wu, Youping; Zhang, Huifeng; Zhang, Liqun; Wang, Bo; Wang, Zhifeng

doi:10.1002/marc.200400380

Cited by 63 publications

(36 citation statements)

References 22 publications

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“…In exfoliated state, the clay layers are completely separated in a continuous polymer matrix and a bigger surface area of dispersed phase is benefit to the formation of hydrogen bonding, which makes it easier for the polymer chains to pack more closely. However, in intercalated and agglomerated states, they are normally interlayer by a few molecular layers of polymer, and the poor interaction between stacked MMT and matrix has little restriction on the segmental mobility due to less contacting area between MMT and matrix [7], which leads to less formation of hydrogen bonding between urethane group and silicate layers. This result shows that the dispersion of MMT within polymer matrix plays a vital role in determining the microstructure.…”

Section: Analysis Of Palsmentioning

confidence: 99%

Influence of MMT content on the microstructure and miscibility for PU/EP IPN nanocomposites by positron

Zhu

Zhou

Wang

et al. 2007

Phys. Status Solidi (c)

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Effects of montmorillonite (MMT) content on the free volume hole and miscibility were first investigated for polyurethane/epoxy resin (PU/EP) interpenetrating polymer network (IPN) nanocomposites by positron annihilation lifetime spectroscopy (PALS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). An exfoliated (IPN/MMT1), a coexistence of exfoliated and intercalated (IPN/MMT3), and an intercalated (IPN/MMT5) structures were confirmed by XRD. Influences of two kinds of hydrogen bonding interactions including both between carbonyl group and N-H group, and the other between urethane group and silicate layers have been discussed. PALS results reveal that the size of the free volume holes decreases after the MMT loaded due to the increase of chain packing efficiency. The large difference between IPN/MMT1 and IPN/MMT5 in the free volume distribution was observed. 1 Introduction Interpenetrating polymer network (IPN) is superior in physical properties to ordinary polymer. It was widely used in engineering, industry and other fields. In recent years, the polymerlayered silicate nanocomposites have attracted considerable attention because of their unique properties. However, little information concerning montmorillonite (MMT) filled IPN and its microstructure has been investigated.Positron annihilation lifetime spectroscopy (PALS) has been become an increasing important method to detect atomic-scale microstructure in polymers currently. It is based on the fact that the lifetimes of positron and positronium (Ps) are sensitive to the existence of structural inhomogeneities, because the formation and annihilation of Ps is localized in nano-or subnanoscale level holes. In this work, the PALS X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were employed to study the effect of MMT content on the microstructure and miscibility for the polyurethane/epoxy resin (PU/EP) IPN nanocomposites.

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Section: Analysis Of Palsmentioning

confidence: 99%

Influence of MMT content on the microstructure and miscibility for PU/EP IPN nanocomposites by positron

Zhu

Zhou

Wang

et al. 2007

Phys. Status Solidi (c)

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“…Many reports point out the significance of PALS in estimating the variations in the type and concentration of the nanofillers. The reduction in free volume was correlated with enhanced interfacial interaction in styrene butadiene rubber/montmorillonite composites by Wang et al [14]. A dependence between the structure and properties of elastomers has also been systematically drawn using PALS.…”

Section: Introductionmentioning

confidence: 94%

Free-volume correlation with mechanical and dielectric properties of natural rubber/multi walled carbon nanotubes composites

Ponnamma

Ramachandran

Hussain

et al. 2015

Composites Part A: Applied Science and Manufacturing

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“…Another recent approach is positron annihilation lifetime spectroscopy for evaluation of the free volume fraction in PLSNCs. 91 …”

Section: Pressure Volume Temperature (Pvt) Behaviourmentioning

confidence: 99%

Recent advances in polymer/layered silicate nanocomposites: An overview from science to technology

Okamoto¹

2006

Materials Science and Technology

140

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Polymer/layered silicate nanocomposites (PLSNCs) offer remarkably improved mechanical and other properties with low inorganic filler loading. The major development in this field has been carried out over the last one and a half decades. However, the authors are far from the goal in terms of understanding the mechanisms of the enhancement effect in the nanocomposites. Continued progress in nanoscale controlling and an improved understanding of the physicochemical phenomena at the nanometre scale have contributed to the rapid development of novel PLSNCs. The present paper describes recent advances in PLSNCs with the primary focus on these advances from basic science to technology.Keywords: Nanocomposite, Layered silicate Introduction A decade of research has shown that nanostructured materials have the potential to significantly impact growth at every level of the world economy in the twenty-first century. This new class of materials is now being introduced in structural applications, such as gas barrier film, flame retardant product and other load bearing applications (see Table 1). 1Of particular interest is recently developed nanocomposites consisting of a polymer and layered silicate (LS), because they often exhibit remarkably improved mechanical and other properties 2 when compared with pure polymer or conventional composites (both micro and macrocomposites). A primary progress in polymer/ layered silicate nanocomposites (PLSNCs), a nylon 6/LS hybrid 3 reported by Toyota Central Research & Development Co. Inc. (TCRD), was successfully prepared by in situ polymerisation of e-caprolactam in a dispersion of montomorrillonite (MMT). The silicate can be dispersed in liquid monomer or a solution of monomer. It has also been possible to melt and mix polymers with layered silicates, avoiding the use of organic solvents. The latter method permits the use of conventional processing techniques such as injection moulding and extrusion.Continued progress in nanoscale controlling and an improved understanding of the physicochemical phenomena at the nanometre scale have contributed to the rapid development of novel PLSNCs. The present paper describes current research on PLSNCs with the primary focus on recent advances from basic science to technology. Historical point of viewEarlier attempts of preparing polymer/LS composites are found in almost half a century old patent literatures. 4,5 In such cases, incorporation of 40-50 wt-% clay mineral (bentonite, hectorite, etc.) into a polymer was attempted but ended up with unsatisfactory results: the maximal modulus enhancement was only y200%, although the clay loading was as much as 50 wt-%. The failure was obvious, because they failed to achieve good dispersion of clay particles in the matrix, in which silicate minerals existed as agglomerated tactoids. Such a poor dispersion of the silicate particles could improve the material rigidity, but certainly sacrificing the strength, the elongation at break and the toughness of the materials. 4,5 A major reason for this impossibil...

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Free Volume of Montmorillonite/Styrene‐Butadiene Rubber Nanocomposites Estimated by Positron Annihilation Lifetime Spectroscopy

Cited by 63 publications

References 22 publications

Influence of MMT content on the microstructure and miscibility for PU/EP IPN nanocomposites by positron

Influence of MMT content on the microstructure and miscibility for PU/EP IPN nanocomposites by positron

Free-volume correlation with mechanical and dielectric properties of natural rubber/multi walled carbon nanotubes composites

Recent advances in polymer/layered silicate nanocomposites: An overview from science to technology

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