X-ray spectrography of polymers and in particular those having a rubber-like extensibility

Κatz, J. R.

doi:10.1039/tf9363200077

Cited by 83 publications

(45 citation statements)

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“…[ 5 ] In contrast to common entropy-elastic materials, NR forms crystals upon strain (strain-induced crystallization (SIC)), which additionally contribute to the cooling of the rubber during relaxation because the necessary heat of fusion Δ h f is taken up from the surrounding. [6][7][8][9][10][11] Altogether the stored cold corresponds to the sum of Δ h f and Δ W .So far only a few materials are known that can store an elongation upon strain-induced crystallization. Unfortunately, the stored strain is less than 100%.…”

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confidence: 99%

Superheated Rubber for Cold Storage

2011

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Supercooled liquids are still considered to be magic materials that can store heat, which is easily to be released with a suited trigger. Storage of cold is much harder to achieve, e.g., by using superheated liquids or liquifi ed gases, which are naturally hard to handle and require laborious equipment. Storing cold with solid materials is not yet realized because superheated solids are generally assumed to be impossible. [ 1 ] Here we report on designed natural rubber (NR) networks that can store cold and release it on a trigger. The unique base of this effect in the NR networks is the ability to form stable crystals upon strain and to stabilize them at the stretching temperature after the stress is released, also retaining up to 1000% elongation. This is a 5-10 times greater strain storage capacity compared to recently described high-tech shape memory materials. [2][3][4] Increasing the temperature to a certain point, called the trigger temperature, results in a spontaneous collapse of the crystals that affords absorption of a signifi cant amount of heat originating from the disruption of the crystals and the relaxation of the rubber itself. This is the fi rst example of a solid material that is capable of storing a signifi cant amount of cold by bringing rubber in a superheated state. Furthermore, we found that the trigger temperature is tunable for one sample in a broad range by varying the stretching conditions.Energy storage is one of the greatest current scientifi c issues. Most systems store energy in the form of electron transfer processes by the heating of matter or pressurizing of gases. Only a few examples are known that use the enthalpy of phase transition (latent heat) for this purpose. The most popular example is the supercooled liquid sodium acetate trihydrate, which does not crystallize until a nucleus is added as trigger. The resulting crystallization releases heat into the environment. In order to have a cold storage system, one would need a material that conserves a superheated state, i.e., the material stores cold that can be released spontaneously via an external trigger. Up to now, such solid materials have been considered impossible. [ 1 ] An interesting way to cool a material is to release the strain of an elastomer. Because the internal energy Δ U of a rubber remains nearly unchanged during deformation ( Δ U = Δ Q -Δ W = 0), the performed work, Δ W , is directly released as heat, Δ Q , during the stretching process and is taken up during its relaxation. This behavior is well-known for NR, which shows a supercooling of up to 10 K by releasing an elongation of λ = 5 (400% strain). [ 5 ] In contrast to common entropy-elastic materials, NR forms crystals upon strain (strain-induced crystallization (SIC)), which additionally contribute to the cooling of the rubber during relaxation because the necessary heat of fusion Δ h f is taken up from the surrounding. [6][7][8][9][10][11] Altogether the stored cold corresponds to the sum of Δ h f and Δ W .So far only a few materials are known that can s...

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Superheated Rubber for Cold Storage

2011

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“…In the liquid and amorphous communities, the peak is called FSDP, and is known to be related to the intermediaterange order [37][38][39][40]. The equivalent peak in polymeric systems is known as the polymerization peak [41,42] or larger than van der Waals peak [43] (or low van der Waals peak [44]). The polymerization peak does not appear in every polymer melt (for example, it is absent in polyethylene melt [14,25,45]), and it is not seen in monomeric systems [41,42].…”

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confidence: 99%

“…The equivalent peak in polymeric systems is known as the polymerization peak [41,42] or larger than van der Waals peak [43] (or low van der Waals peak [44]). The polymerization peak does not appear in every polymer melt (for example, it is absent in polyethylene melt [14,25,45]), and it is not seen in monomeric systems [41,42]. Whereas the higher momentum-transfer peak is observed in all polymer glasses and melts and as such it is normally called the main peak [25,42] or van der Waals peak [43,44].…”

Section: Resultsmentioning

confidence: 99%

“…In polymers, the polymerization peak is usually assigned to backbonebackbone correlation [25,[41][42][43][44][45][46], which could also be thought of as a correlation of dense backbones surrounding voids that are sparsely filled by the side chains; a picture that is particularly true for P4MP1, because the side chains are bulky and inefficiently packed [23][24][25]. In fact, the polymerization peak in our measurements occurs at 0.6Å −1 , which corresponds to 2π/(0.6Å −1 ) ≈ 10.5Å in real space, which is consistent with the expected interbackbone distance for the melt (the distance is evaluated from that for the crystalline state [23][24][25]).…”

Section: Resultsmentioning

confidence: 99%

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Pressure-induced structural change of intermediate-range order in poly(4-methyl-1-pentene) melt

et al. 2012

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High-pressure in situ x-ray diffraction and specific-volume measurements on isotactic poly(4-methyl-1-pentene) melt have uncovered abrupt changes in the pressure dependence of microscopic structure as well as that of macroscopic density. The first sharp diffraction peak of the polymer melt, which is related to the intermediate-range order and is explained as resulting from the correlations between main chains, is suppressed at pressures less than 1 kbar. These changes in intermediate-range order show similarities to those seen in liquid-liquid or amorphous-amorphous transitions in simpler small molecule based systems, suggesting that this kind of phenomenon may occur in a wide range of materials.

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“…These polymer/clay nanocomposites are classified into a new family of engineering plastics in respect of their higher strength, higher modulus, higher heat distortion temperature, and lower gas permeability. 6) In previous studies about WAXS observation of PS [7][8][9][10][11] , it was shown that the two characteristic peaks were observed at q=7.5 nm − 1 (inner peak) and 10.0 nm − 1 (outer peak)…”

Section: Introductionmentioning

confidence: 99%

Filler-Induced Structural Order and Mechanical Properties of Polystyrene-Silica Nanocomposites

Kondo

Someya

Yamada

et al. 2005

J. Soc. Rheol., Jpn

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This study is concerned with the relationship between wide angle X-ray scattering (WAXS) analysis and physical properties of amorphous polystyrene (PS)-silica (SiO 2 ) composites. Nanoporous SiO 2 for the fillers was prepared by the hydrothermal reaction and the structures of the composites were examined by WAXS. In their WAXS patterns, two characteristic peaks, inner peak and outer peak, were observed at q 7 nm −1 and 15 nm −1 corresponding to the intermolecular structure of PS chains and the intramolecular order of benzene rings, respectively. The ratio (I in ⁄I out =P) in intensity of the inner peak (I in ) to outer peak (I out ) affords the structural parameter to well characterize the intermolecular and intramolecular structures of PS molecules and the P values are observed to change widely from 0.183 to 1.16 depending on the material compositions. The elongation at the break point increases monotonously with increasing P, whereas the yield strength and the Young's modulus decrease with P for P=0.497 or below but remain almost constant for larger P values. The elongation of 4.5% for (PS+MPS) / SiO 2 is enormously larger than those for PS and the other composites, in contrast to a slight decrease of the other two properties relative to those for PS. It is also revealed that a strong interaction works between the COO or COOH groups of maleic anhydride modified polystyrene (MPS) and the OH groups of SiO 2 , which makes the PS polymer molecules to stack regularly on SiO 2 nanofillers, leading to control the physical properties of the composites.

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X-ray spectrography of polymers and in particular those having a rubber-like extensibility

Cited by 83 publications

References 0 publications

Superheated Rubber for Cold Storage

Superheated Rubber for Cold Storage

Pressure-induced structural change of intermediate-range order in poly(4-methyl-1-pentene) melt

Filler-Induced Structural Order and Mechanical Properties of Polystyrene-Silica Nanocomposites

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