Network formation and elasticity evolution in dibenzylidene sorbitol/poly(propylene oxide) physical gels

Dumitraș, Mihai; Friedrich, Chr.

doi:10.1122/1.1781169

Cited by 23 publications

(23 citation statements)

References 40 publications

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“…The onset of gel formation has been characterised by a gel concentration range rather than by a gel point for DBS/poly(propylene oxide). [17] A monotectic phase diagram of p-DMDBS/ iPP [18] was established and the development of organised structures for sheared melts was followed in real time by X-ray scattering. [19] Owing to their unique activity as CA, the concept of self-assembling or butterflyshaped molecules has been taken up again to design potential NA or better CA.…”

Section: Gelling Nucleating Agents Clarifying Agentsmentioning

confidence: 99%

Organogelators and Polymer Crystallisation

Thierry

Straupé

Wittmann

et al. 2006

Macromolecular Symposia

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The specific impact of low molecular weight organic gels on polymer crystallisation is examined. Conventional nucleating agents (NA) influence the polyolefins crystallisation and improve their mechanical properties, via an epitaxial mechanism. In the particular case where the pair NA/polymer form a gel at intermediate temperatures on cooling, optical properties (clarity) are significantly improved. This improvement is linked with the ability of organic gels to develop 3-D fibrillar network. The fibres morphology offers a large specific area, thus produces a high density of nuclei, homogeneously dispersed. Gelling organic molecules are certainly a promising route towards the design of efficient additives in polymer processing.

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Section: Gelling Nucleating Agents Clarifying Agentsmentioning

confidence: 99%

Organogelators and Polymer Crystallisation

Thierry

Straupé

Wittmann

et al. 2006

Macromolecular Symposia

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“…According to the previous literature, the matrix polarity, molecular weight, and DBS concentration influence gel formation and the rheological properties of the DBSinduced organogels. 5,10,[21][22][23][24] Here, we report the effects of DBS concentration on dynamic rheological data (elastic modulus G 0 and viscous modulus G 00 ) of DBS/PPG organogels. Moreover, we find that there is a certain period of time required for DBS/PPG organogels to reach equilibrium.…”

Section: Introductionmentioning

confidence: 99%

Studies on the self‐assembly of neat DBS and DBS/PPG organogels

Lai

2009

J of Applied Polymer Sci

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The self-assembly behavior of neat 1,3:2,4-dibenzylidene-D-sorbitol (DBS) and DBS/poly(propylene glycol) (PPG) organogels has been investigated by scanning electron microscopy, polarizing optical microscopy, and rheological measurements. DBS molecules are capable of selforganizing into fibrils and exhibit the birefringent spherulitic textures during cooling from the melt. On the other hand, DBS can self-assemble into a fibrillar network in PPG to produce organogels. DBS/PPG organogels also reveal a spherulite-like morphology. When a small amount of DBS is dispersed into a PPG matrix, we find that the spherulite sizes are much smaller than those of neat DBS. This is because the dilution of DBS causes DBS to self-assemble in PPG at a lower temperature. Therefore, more nucleation sites and smaller spherulite sizes are found in the DBS/PPG organogel system. The rheological measurements demonstrate that the elastic modulus (G 0 ) in DBS/PPG organogels increases as the DBS concentration increases. However, the increase in G 0 is less obvious, as the DBS content exceeds 3 wt %. suggesting that the DBS networks become saturated. Also, it is found that these organogels require a certain period of time to reach thermodynamic equilibrium, depending on DBS concentrations.

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“…Usually, when polymers form chemical or physical networks, the viscoelastic behaviors will exhibit sharp transitions from liquid to solid behaviors. These transition points are so called gel points, which may be critical temperature, time, and concentration of polymers or fillers . There are many ways to obtain the gel points, a popular method is according to the fact tan δ shows no dependence on ω at the gel point.…”

Section: Resultsmentioning

confidence: 99%

Comprehensively improved mechanical properties of silane crosslinked polypropylene/ethylene propylene diene monomer elastomer blends

Peng

Wang

et al. 2020

Polymer Engineering & Sci

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The properties and structure of silane crosslinked polypropylene (PP)/ethylene propylene diene monomer (EPDM) elastomer blends had been carried out. Fourier transform infrared spectroscopy and gel content tests were employed to evaluate the crosslinking reaction of PP/EPDM blends. Crosslinking efficiency of PP/EPDM blends was investigated using thermogravimetric analysis, differential scanning calorimeter, dynamic mechanical analysis, dynamic rheology, and tensile testing. Tanδ curves of silane crosslinked PP/EPDM blends exhibited an obvious "gel point" originated from the formation of dynamic crosslinking network. The blend corresponding to the "gel point" presented comprehensively improved mechanical properties. These results demonstrated that characteristic rheological parameters showed close correlations with key mechanical properties of silane crosslinked PP/EPDM blends. Scanning electron microscopy images illustrated that crosslinking had remarkably changed the morphologies of PP/EPDM blends. The large deformation mechanism of these blends had been suggested.

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Network formation and elasticity evolution in dibenzylidene sorbitol/poly(propylene oxide) physical gels

Cited by 23 publications

References 40 publications

Organogelators and Polymer Crystallisation

Organogelators and Polymer Crystallisation

Studies on the self‐assembly of neat DBS and DBS/PPG organogels

Comprehensively improved mechanical properties of silane crosslinked polypropylene/ethylene propylene diene monomer elastomer blends

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