Preparation and thermal properties of polystyrene/silica nanocomposites

Bera, Oskar; Pilić, Branka; Pavličević, Jelena; Jovičić, Mirjana; Holló, Berta Barta; Szécsényi, Katalin Mészáros; Špírková, Miléna

doi:10.1016/j.tca.2010.12.006

Cited by 66 publications

(46 citation statements)

References 30 publications

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“…[19][20][21][22][23][24][25][26][27][28] As a secondary aim of this work, we evaluate the glass transition behavior of the silica nanoparticle-containing PS nanocomposite as a function of pressure, as well as cooling rate. T g is important for practical reasons because it determines processing and use temperatures, and for composites based on amorphous polymeric matrices, the stress-free temperature is often considered to coincide with the glass transition temperature 29,30 which, in turn, depends on cooling rate.…”

Section: Introductionmentioning

confidence: 99%

Pressure‐volume‐temperature and glass transition behavior of silica/polystyrene nanocomposite

Tao

Simon

2015

J Polym Sci B Polym Phys

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The pressure-volume-temperature (PVT) behavior and glass transition behavior of a 10 wt % silica nanoparticlefilled polystyrene (PS) nanocomposite sample are measured using a custom-built pressurizable dilatometer. The PVT data are fitted to the Tait equation in both liquid and glassy states; the coefficient of thermal expansion a, bulk modulus K, and thermal pressure coefficient c are examined as a function of pressure and compared to the values of neat PS. The glass transition temperature (T g ) is reported as a function of pressure, and the limiting fictive temperature (T f 0 ) from calorimetric measurements is reported as a function of cooling rate. Comparison with data for neat PS indicates that the nanocomposite has a slightly higher T g at elevated pressures, higher bulk moduli at all pressures studied, and its relaxation dynamics are more sensitive to volume. The results for the glassy c values suggest that thermal residual stresses would not be reduced for the nanocomposite sample studied. INTRODUCTION In fiber-reinforced polymer composites, the build-up of residual stresses induced by the mismatch in thermal expansivities between filler and matrix is often inevitable during processing and application. These isotropic thermal residual stresses, which can lead to early failure or suboptimal performance of a material, depend on the thermal pressure coefficient c, which in turn depends on the product of the bulk modulus K (52V(@P/@V) T ) and the isobaric thermal expansion coefficient a p (51/V(@V/@T) P ).

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Section: Introductionmentioning

confidence: 99%

Pressure‐volume‐temperature and glass transition behavior of silica/polystyrene nanocomposite

Tao

Simon

2015

J Polym Sci B Polym Phys

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“…The addition of 0.5% multiwalled carbon nanotubes (MWCNTs) increased the flexural strength of PMMA by an average of 9.3, but 2% addition of MWCNTs resulted in a 11.4% decrease in flexural strength due to the poor dispersion of MWCNTs 27) . Compared with researches of the similar kind [11][12][13][14][15] , the 13.5% increase in flexural strength of PMMA by addition of PI in this study could be satisfying.…”

Section: Discussionmentioning

confidence: 45%

“…Many investigations have focused on nanoparticle addition to strengthen PMMA, such as addition of nanosilica 11) , carbon nanotube 12) or TiO2 and SiO2 nanoparticles 13) , and some of them have shown progress. But on the other hand, decreased mechanical properties of PMMA resulted from nanoparticle addition have also been reported 14,15) . Polyimide (PI) is a macromolecule polymer material, owning the collective advantages of excellent thermal stability, mechanical properties and chemical resistance.…”

Section: Introductionmentioning

confidence: 99%

Effect of polyimide addition on mechanical properties of PMMA-based denture material

Yang

Zhao

et al. 2017

Dent. Mater. J.

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The aim of the study was to evaluate the effect of modifying polymethyl methacrylate (PMMA) denture base material with polyimide (PI) on its flexural property and biocompatibility. Low molecular weight (1,500 g/mol) PI was synthesized and small amount of PI (0.4, 0.6, 0.8 and 1 wt%) was dispersed into the PMMA matrix. Three-point bending tests, scanning electron microscopy and thermal cycling were used to measure the mechanical properties, while MTT assay was used to evaluate the biocompatibility of the denture base material. The results showed that 0.6% addition of PI significantly increased flexural strength of PMMA denture base material by 13.5%, compared with the control group (p<0.05). Even after 5,000 hydrothermal cycling the reinforce effect still existed. However, when the PI content further increased, flexural strength of the denture base material decreased due to particle agglomeration. The MTT assay confirmed that the addition of PI did not change the biocompatibility of the PMMA denture base material. The present study suggested that blending polyimide in the proper proportion can be a potential method to strengthen the PMMA-based denture base material.

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“…Hydrophobic fumed silica Aerosil R8200, surface-modified with hexamethyldisilazane and with primary particle size of 12 nm, was used. Reinforcement of polyester systems with fumed silicas has been previously reported in literature [12][13][14]. 5 wt.% silica powder was added to the organic phase prior to emulsification of the aqueous phase, yielding a homogenous and stable dispersion.…”

Section: Table 1 Ftir Peak Intensity Ratiosmentioning

confidence: 99%

“…11 shows that silica-reinforced particles present a 75% increase in storage modulus below glass transition. Nano-silica loading also promotes a positive displacement in the damping coefficient peak, causing Tg to increase from 121 o C to about 140 o C. This is a consequence of homogeneous nano-filler dispersion and good interaction with the polymer matrix [13]. …”

Section: Table 1 Ftir Peak Intensity Ratiosmentioning

confidence: 99%

Physicomechanical characterization of monodisperse multivesiculated polyester particles

Fidalgo¹,

Mendes²,

Magalhães³

2014

European Polymer Journal

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This work describes physicomechanical properties of low-density polyester particles with multialveolar inner morphology, obtained via a water/oil/water double emulsion process. Monodisperse particle diameters were produced thanks to the use of a microchannel T-junction device for droplet generation. The drying conditions tested showed that rapid water evaporation at 120 o C, combined with slow diffusion towards the exterior, causes internal fracture and particle deformation. Interestingly, all particles present virtually identical internal damage and external deformation features under these drying conditions, demonstrating the uniformity in internal structures. Drying at 70 o C allows for efficient water removal with no damage. Thermomechanical transitions and thermal stability were analyzed by dynamic mechanical analysis (DMA in single-particle compression mode), dynamic scanning calorimetry (DSC) and thermogravimetry (TG). The effectiveness of curing conditions was evaluated by FTIR and DSC, allowing to identify the need of a thermal post-treatment for consumption of residual styrene. The consequent increase in degree of crosslinking produced a positive shift in glass transition temperature measured by DMA. Finally, mechanical reinforcement of the multivesiculated polyester particles was obtained by loading the polymer with surface-modified fumed silica, yielding 75% increase in storage modulus.

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Preparation and thermal properties of polystyrene/silica nanocomposites

Cited by 66 publications

References 30 publications

Pressure‐volume‐temperature and glass transition behavior of silica/polystyrene nanocomposite

Pressure‐volume‐temperature and glass transition behavior of silica/polystyrene nanocomposite

Effect of polyimide addition on mechanical properties of PMMA-based denture material

Physicomechanical characterization of monodisperse multivesiculated polyester particles

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