Diffusion of Poly(dimethylsiloxane) Mixtures with Silicate Nanoparticles

Roberts, Claire; Cosgrove, Terence; Schmidt, Randall G.; Gordon, Glenn V.

doi:10.1021/ma001245z

Cited by 64 publications

(78 citation statements)

References 19 publications

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“…It is not clear what mechanism causes the reduction of melt viscosity in the nanocomposites with low GO loading. One possibility is acting of GO sheets as plasticizer, increasing the free volume and therefore decreasing the melt viscosity [36]. Whereas at higher GO loading, the polymer-GO and GO-GO interactions are predominate and causes increase the melt bulk viscosity.…”

Section: Physical Properties Of Nanocompositesmentioning

confidence: 99%

Structure and properties of nanocomposites based on PTT-block-PTMO copolymer and graphene oxide prepared by in situ polymerization

Paszkiewicz¹,

Szymczyk²,

Špitálský³

et al. 2014

European Polymer Journal

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a b s t r a c tPoly(trimethylene terephthalate-block-tetramethylene oxide) (PTT-PTMO) copolymer/ graphene oxide nanocomposites were prepared by in situ polymerization. From the SEM and TEM images of PTT-PTMO/GO nanocomposite, it can be seen that GO sheets are clearly well-dispersed in the PTT-PTMO matrix. TEM images also showed that graphene was well exfoliated into individual sheets, suggesting that in situ polymerization is a highly efficient method for preparing nanocomposites. The influence of GO on the two-phase structure, melt viscosity and mechanical properties of PTT-PTMO block copolymer was examined by using DSC, ARES rheometer and tensile tests. The DSC results imply that the introduction of GO did not affect the glass transition temperature of PTMO-rich soft phase, melting temperature of PTT hard phase and degree of crystallinity of the nanocomposites. As the graphene oxide loading in the nanocomposites increase, the enhanced Young's modulus and yield stress was observed. The tensile strength slightly increased with the increase of GO from 0 to 0.5 wt% when elongation at break was higher or comparable to the value of neat PTT-PTMO copolymer.

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Section: Physical Properties Of Nanocompositesmentioning

confidence: 99%

Structure and properties of nanocomposites based on PTT-block-PTMO copolymer and graphene oxide prepared by in situ polymerization

Paszkiewicz¹,

Szymczyk²,

Špitálský³

et al. 2014

European Polymer Journal

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“…Several publications cite these effects for polymer systems though the techniques and samples available for this work preclude a more detailed study. However, as we have shown in previous publications 19,20 a good qualitative description can be made by using the averaged relaxation time and these are the values plotted in the subsequent figures. Figure 6 shows plots of the spin-spin relaxation rate (1/T 2 ) as a function of molecular weight of the PDMS segment: reduced molecular mobility of polymers is indicated by an increase in relaxation rate.…”

Section: Diffusion Nmr Spectroscopymentioning

confidence: 74%

“…19,26 An acid-catalyzed polymerization of sodium silicate followed by a reaction with trimethylchlorosilane in a process described elsewhere 27 -using an equivalent molar ratio of trimethylsiloxy and silicate units-produced this amorphous nanoparticle with a weight-average radius of gyration of 1.5 nm and glass transition temperature of 96 ± 3 o C by dynamic mechanical thermal analysis.…”

Section: Trimethylsiloxy Polysilicate Nanoparticlesmentioning

confidence: 99%

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Impact of End-Tethered Polyhedral Nanoparticles on the Mobility of Poly(dimethylsiloxane)

et al. 2015

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A series of dumbbell-shaped nanocomposite materials of poly(dimethylsiloxanes) (PDMSs) and polyhedral oligomeric silsesquioxanes (POSSs) were synthesized through hydrosilylation reactions of allyl-and vinyl-POSS and hydrideterminated PDMS. The chemical structures of the dumbbellshaped materials, so-called POSS-PDMS-POSS triblocks, were characterized by 1 H NMR and FT-IR spectroscopy. The molecular weights of the triblock polymers were determined by gel permeation chromatography (GPC). Their size was analyzed by small-angle neutron scattering (SANS) and pulsed-field gradient stimulated echo (PFG STE) NMR experiments. The impact of POSS on the molecular mobility of the PDMS middle chain was observed by using 1 H spin−spin (T 2 ) relaxation NMR. In contrast to the PDMS melts, the triblocks showed an increase in mobility with increasing molecular weight over the range studied due to the reduced relative concentration of constraints imposed by the end-tethered nanoparticles. The triblock systems were used to compare the impact of tethered nanoparticles on the mobility of the linear component compared to the mobility of the polymer in conventional blended nanocomposites. The tethered nanoparticles were found to provide more reinforcement than physically dispersed particles especially at high molecular weights (low particle concentration). The physical blends showed an apparent percolation threshold behavior.

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“…In this process, uniformly dispersed nanoparticles reduce the entanglement of polymer chains while the blend viscosity reduces with the free volume associated with the nanoscale filler or particles, due to the rigid and stiff characteristics of the length sorted single-walled carbon nanotubes (SWNTs) rendering non-Einstein-like behavior. Roberts et al [11] found that clusters of silica caused viscosity reduction to the linear poly(dimethylsiloxane) when the nanoparticles were less than 0.7 nm in size, which facilitated plasticizing effects. Tuteja et al used PS nanoparticles and studied its viscosity reduction effect, at different molecular weights of the linear PS matrix [12].…”

Section: Introductionmentioning

confidence: 99%

Viscosity and Morphology Modification of Length Sorted Single-Walled Carbon Nanotubes in PIB Matrices

Huang

Simien

et al. 2017

Journal of Nanomaterials

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This work evaluates the effectiveness of nanoscale particulates in producing non-Einstein-like responses in polymer matrices, to reduce their negative effects in low shear rate processing. This is of value to material processing applications which encompass extrusion, flow into cold mold, and generalized processing of nanocomposites. Through control and understanding of the structure processing relationships entailed through nanoscale additive materials, we begin to manage dispersion characteristics for more reliable and defect-free product development. In pursuit of identifying system characteristics that produce non-Einstein-like responses we isolate and characterize homogenous fractions of single-walled carbon nanotubes (SWNTs) with singular lengths. This enables the definition of a well-defined nanoscale particulate phase, within the polymer matrices. The effect of nanotube length and weight fraction on the polyisobutylene (PIB) matrices was evaluated with thermal and rheological testing. Our findings show that the viscosity of the produced nanocomposite systems has a length dependence and does not demonstrate the expected monotonous increases in the viscosity with an increase in weight fraction of nanotube additive within the matrix, demonstrating a non-Einstein-like viscosity response. Furthermore, we demonstrate length dependent crystallization in the studied systems, as an intermediate length nanotube initiates crystallization of polyisobutylene (PIB) affecting viscosity and mechanical properties.

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Diffusion of Poly(dimethylsiloxane) Mixtures with Silicate Nanoparticles

Cited by 64 publications

References 19 publications

Structure and properties of nanocomposites based on PTT-block-PTMO copolymer and graphene oxide prepared by in situ polymerization

Structure and properties of nanocomposites based on PTT-block-PTMO copolymer and graphene oxide prepared by in situ polymerization

Impact of End-Tethered Polyhedral Nanoparticles on the Mobility of Poly(dimethylsiloxane)

Viscosity and Morphology Modification of Length Sorted Single-Walled Carbon Nanotubes in PIB Matrices

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