Pressure-Induced Polymerization in Solid Ethylene

Chelazzi, David; Ceppatelli, Matteo; Santoro, Mario; Bini, Roberto; Schettino, Vincenzo

doi:10.1021/jp0536495

Cited by 84 publications

(105 citation statements)

References 28 publications

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“…In our case, when either part or almost the full sample region is occupied by silicalite powder, we observe in the middle of the sharp doublet, due to bulk PE, a strong and broad single-chain bending peak at 1,468 cm À 1 with shoulders at 1,458 and 1,445 cm À 1 , and two broad wagging mode bands at 1,353 and 1,370 cm À 1 . The shoulders and the wagging peaks, which are very weak in the bulk polymer 21,31 , are entirely due to gauche defects. All these peaks correspond to disordered PE with gauche defects among others, which we assign to confined PE in the micro-channels of silicalite.…”

Section: Synthesis Of Pesilmentioning

confidence: 92%

High-pressure synthesis of a polyethylene/zeolite nano-composite material

et al. 2013

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Meso/micro-porous solids, such as zeolites, are complex materials used in an impressive range of applications. Here we photo-polymerized ethylene using non-catalytic high-pressure techniques at 0.5-1.5 GPa under ultraviolet (351-364 nm) irradiation on a sub-nanometre scale in the channels of a pure SiO 2 zeolite, silicalite, to obtain a unique nano-composite material with drastically modified mechanical properties. The structure obtained contains single polyethylene chains, which adapt very well to the confining channels as shown by optical spectroscopy and X-ray diffraction. The formation of this nano-composite results in significant increases in bulk modulus and density, and the thermal expansion coefficient changes sign from negative to positive with respect to silicalite. Mechanical properties may thus be tuned by varying the amount of polymerized ethylene. Our findings could allow the high-pressure, catalyst-free synthesis of a unique generation of technological, functional materials based on simple hydrocarbons polymerized in confining meso/micro-porous solids.

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Section: Synthesis Of Pesilmentioning

confidence: 92%

High-pressure synthesis of a polyethylene/zeolite nano-composite material

et al. 2013

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“…This method has obvious advantages: (i) the product tends to be of high purity; (ii) waste and toxicity aspects of catalysts are avoided; (iii) the reaction is performed in bulk without solvents; and (iv) potentially materials can be made that are unattainable at ambient pressure. There have been a few publications describing pressure-induced polymerization in unsaturated, hydrocarbons such as ethylene [6,7], propylene [8], benzene [9,10], isoprene [11,12], styrene [13], and butadiene [2,14]. In the case of ethylene, isoprene, and butadiene, laser irradiation of the system under high pressure can lead to new reaction pathways, producing unique polymer products.…”

Section: Introductionmentioning

confidence: 99%

Pressure-induced polymerization of phenoxyethyl acrylate

Kamiński¹,

Wrzalik²,

Paluch³

et al. 2008

J. Phys.: Condens. Matter

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“…The formation of extended covalently bonded solids has been observed through pressurizing simple molecular systems (1). High-quality polymeric materials have been recovered at ambient conditions by high-pressure processing of small hydrocarbon molecules (2)(3)(4)(5), demonstrating the potential of this approach for synthesis. In addition, attractive amorphous materials have been obtained by compressing model compounds.…”

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confidence: 99%

Role of excited electronic states in the high-pressure amorphization of benzene

Citroni¹,

Bini

Foggi

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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High-pressure methods are increasingly used to produce new dense materials with unusual properties. Increasing efforts to understand the reaction mechanisms at the microscopic level, to set up and optimize synthetic approaches, are currently directed at carbon-based solids. A fundamental, but still unsolved, question concerns how the electronic excited states are involved in the high-pressure reactivity of molecular systems. Technical difficulties in such experiments include small sample dimensions and possible damage to the sample as a result of the absorption of intense laser fields. These experimental challenges make the direct characterization of the electronic properties as a function of pressure by linear and nonlinear optical spectroscopies up to several GPa a hard task. We report here the measurement of two-photon excitation spectra in a molecular crystal under pressure, up to 12 GPa in benzene, the archetypal aromatic system. Comparison between the pressure shift of the exciton line and the monomer fluorescence provides evidence for different compressibilities of the ground and first excited states. The formation of structural excimers occurs with increasing pressure involving molecules on equivalent crystal sites that are favorably arranged in a parallel configuration. These species represent the nucleation sites for the transformation of benzene into amorphous hydrogenated carbon. The present results provide a unified picture of the chemical reactivity of benzene at high pressure.benzene crystal ͉ electronic transitions ͉ high-pressure chemistry ͉ two-photon spectroscopy

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Pressure-Induced Polymerization in Solid Ethylene

Cited by 84 publications

References 28 publications

High-pressure synthesis of a polyethylene/zeolite nano-composite material

High-pressure synthesis of a polyethylene/zeolite nano-composite material

Pressure-induced polymerization of phenoxyethyl acrylate

Role of excited electronic states in the high-pressure amorphization of benzene

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