High-energy mechanical milling of poly(methyl methacrylate), polyisoprene and poly(ethylene- alt -propylene)

Smith, A. P.; Shay, Jennifer S.; Spontak, Richard J.; Balik, C. M.; Ade, Harald; Smith, Steven D.; Koch, Carl C.

doi:10.1016/s0032-3861(99)00830-7

Cited by 84 publications

(73 citation statements)

References 34 publications

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“…This effect is exemplified by PI, which contains a high level of unsaturation along the backbone and readily undergoes chemical crosslinking upon high-energy irradiation [21]. In a similar vein, cryogenic mechanical milling of PI has also been found [14] to promote chemical crosslinking. Fig.…”

Section: Molecular Characteristicsmentioning

confidence: 93%

“…The time independence of solubility after 1 h indicates that crosslinking occurs quickly and that a steady state ensues wherein chain crosslinking and scission occur at nearly equal rates. This steady state is attributed to an increase in chain scission efficiency with increasing molecular weight [14,29,30]. High-energy mechanical milling of PMMA, however, results in a rapid and dramatic decrease in molecular weight [14].…”

Section: Molecular Characteristicsmentioning

confidence: 99%

“…Similar behavior is observed during mechanical milling, as evidenced by the data provided in Table 1. The values of M w of PMMA and PS measured by GPC are listed [14], as is the M v of PET from viscometry measurements [33], before and after cryomilling. 2 The t c listed in Table 1 are conceptually inversely proportional to G-values, and proportional to a scissioning probability.…”

Section: Molecular Characteristicsmentioning

confidence: 99%

“…Two issues that must be overcome for this technique to become a viable processing strategy are the molecular weight degradation during alloying [14] and phase coarsening that proceeds during post-processing in the melt [17]. By recognizing that polymers respond in similar fashion to both high-energy irradiation and mechanical milling, and relying upon the body of knowledge accumulated from radiation damage studies of polymers, these identified shortcomings can be addressed in an expedient manner.…”

Section: Extension To Mechanical Alloyingmentioning

confidence: 99%

“…In several companion works, we have recently reported the effect of high-energy mechanical milling on the molecular characteristics of poly(methyl methacrylate) (PMMA), poly(ethylene-alt-propylene) (PEP) and polyisoprene (PI) [14], as well as the utility of high-energy cryogenic mechanical alloying to blend PMMA with either PEP or PI [15][16][17], poly(ethylene terephthalate) (PET) with poly(oxybenzoate-r-2-6-oxynaphthoate) (Vectra 1 ) [18], and PET with recycled tire [19]. An unexpected implication of our findings is that the molecular response of polymers subjected to high-energy ball milling appears mechanistically similar to that resulting from high-energy irradiation.…”

Section: Introductionmentioning

confidence: 99%

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On the similarity of macromolecular responses to high-energy processes: mechanical milling vs. irradiation

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2001

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Section: Molecular Characteristicsmentioning

confidence: 93%

Section: Molecular Characteristicsmentioning

confidence: 99%

Section: Molecular Characteristicsmentioning

confidence: 99%

Section: Extension To Mechanical Alloyingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the similarity of macromolecular responses to high-energy processes: mechanical milling vs. irradiation

Smith

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2001

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X‐ray Microscopy

Ade

2002

Encyclopedia of Polymer Science and Technology

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During the last few years near edge x‐ray absorption fine structure (nexafs) spectroscopy/microscopy has evolved into a useful characterization tool for polymer science, providing quantitative compositional mapping with minimal radiation damage at a spatial resolution of presently about 40 nm. This article reviews the spectroscopic principles of nexafs, discusses some polymer nexafs reference spectra to illustrate the underlying utility of nexafs spectroscopy to nexafs microscopy, and provides an overview of the state‐of‐the‐art of x‐ray microscopy instrumentation. Applications of nexafs microscopy are wide ranging and include mapping the composition of polymer thin films and their surfaces, as well as the composition of ultrathin sections of bulk materials ranging from polymer blends to multilayers. To date, nexafs microscopy is still a specialized technique that requires powerful synchrotron radiation sources, similar to established polymer science tools such as neutron and x‐ray small‐angle scattering and reflectivity.

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Chain‐Scission‐Induced Intercalation as a Facile Route to Polymer Nanocomposites

2007

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Polymer/clay nanocomposites (NCs) prepared using melt intercalation must be properly formulated and processed to achieve intercalation or exfoliation. Organically modified layered silicates (OMLSs) are often used to permit polymer intercalation and thereby separate the silicate platelets. Prior modeling efforts [1] suggest that high-molecular-weight (HMW) polymers tend to yield immiscible NCs unlike their low-molecular-weight (LMW) analogs, which commonly result in exfoliated or intercalated NCs. Although formulations containing LMW polar additives (e.g., maleic anhydride copolymers) have succeeded in producing at least partially exfoliated rather than immiscible NCs, [2][3][4] a need persists for simpler HMW formulations in order to expedite industrial scale-up. The present study examines blends composed of HMW polystyrene (PS) and an OMLS that remains largely immiscible when annealed under an inert N 2 atmosphere with little or no shear. Controlled thermal-oxidative chain scission of the HMW PS in an O 2 -rich environment promotes intercalation of short PS chains within the OMLS, thereby expanding and disordering the platelets as an intercalated NC develops. This scission-induced intercalation mechanism ensures that the resultant NC is in a thermodynamically stable state unlike NCs prepared using in situ polymerization, which may deintercalate during further processing. [5,6] Moreover, scission intercalation may be used as a general means by which to promote intercalation or possibly exfoliation in previously reported [4,7,8] immiscible NCs.Polymeric NCs containing clay have become an increasingly important topic in the development of lightweight, [9][10][11][12] tough, [13][14][15][16][17][18][19] and impermeable [18][19][20][21] materials since the Toyota research laboratories polymerized nylon-6 in the presence of sodium montmorillonite (Na-MMT) for automotive applications in the late 1980s. [22] In situ polymerization has enjoyed the most success in producing exfoliated NCs wherein individual clay platelets are uniformly dispersed in a polymeric matrix, because the polymer chains can grow within the silicate galleries. Another NC-fabrication strategy is solution intercalation, [23] in which polymer, solvent, and clay are mixed together. In this case, confinement of polymer chains upon diffusion into the silicate galleries is compensated for by the entropic gain caused by desorbed solvent molecules. Both in situ polymerization and solution intercalation typically require relatively large quantities of organic solvent, whereas melt intercalation [24] relies on annealing above the glass-transition (T g ) or melting (T m ) temperature of the polymer matrix under static or shear conditions. Melt intercalation constitutes an environmentally benign and commercially feasible process that successfully yields intercalated or exfoliated NCs from more polymer-clay pairs than either in situ polymerization or solution intercalation. Giannelis and co-workers [24][25][26] have previously demonstrated that sieved PS powder ...

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High-energy mechanical milling of poly(methyl methacrylate), polyisoprene and poly(ethylene- alt -propylene)

Cited by 84 publications

References 34 publications

On the similarity of macromolecular responses to high-energy processes: mechanical milling vs. irradiation

On the similarity of macromolecular responses to high-energy processes: mechanical milling vs. irradiation

X‐ray Microscopy

Chain‐Scission‐Induced Intercalation as a Facile Route to Polymer Nanocomposites

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