Structural heterogeneities and mechanical properties of vinyl/dimethacrylate networks synthesized by thermal free radical polymerisation

Rey, Laurent; Duchet, Jannick; Galy, Jean; Sautereau, H.; Vouagner, D.; Carrion, Lionel

doi:10.1016/s0032-3861(02)00266-5

Cited by 89 publications

(97 citation statements)

References 19 publications

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“…It has been observed that the more densely crosslinked polymer is more heterogeneous and the crack in such polymer materials propagates in the regions with a relatively low crosslinking density between highly crosslinked clusters, which is consistent with our findings [28].…”

Section: Results and Discussion 31 Particles Morphologysupporting

confidence: 93%

“…During the synthesis of particles, the polymerization is a coupled process of chemical (reaction) control and diffusion control. Resulting from an inhomogeneous distribution of crosslinking monomer, an inhomogeneous microstructure consisting of granules can form [28]. The granules can be considered as the aggregates of typically tiny particles with higher crosslinking density than the average.…”

Section: Results and Discussion 31 Particles Morphologymentioning

confidence: 99%

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Crosslinking effect on the deformation and fracture of monodisperse polystyrene-co-divinylbenzene particles

He¹,

Zhang²,

Kristiansen³

et al. 2013

Express Polym. Lett.

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Abstract. This study focuses on the effect of crosslinking density on the mechanical response of polystyrene-co-divinylbenzene (PS-DVB) particles under compression by means of nanoindentation-based flat punch method combined with SEM observation of particle morphologies. The monodisperse PS-DVB particles with about 5 !m in diameter are produced by the Ugelstad activated swelling method and the crosslinking density defined as the weight percentage of activated crosslinker DVB during the preparation process varies from 2.0 to 55.3%. Results show that the particle stress-strain behaviour is independent of the crosslinking density if the strain is less than 10%. With increasing strain level over 10%, a higher crosslinking leads to a stiffer behaviour of the particles. While slightly crosslinked (2.0 and 5.0 wt%) particles undergo plastic deformation with crazing and residual strain, highly crosslinked (21.3, 32.0 and 55.3 wt%) counterparts experience perfectly viscoelastic deformation. The crosslinking density significantly influences the fracture property as well as the failure morphology. Slightly crosslinked particles become permanently deformed after compression, while highly crosslinked ones are entirely fragmented once a critical strain is reached.

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Section: Results and Discussion 31 Particles Morphologysupporting

confidence: 93%

Section: Results and Discussion 31 Particles Morphologymentioning

confidence: 99%

Crosslinking effect on the deformation and fracture of monodisperse polystyrene-co-divinylbenzene particles

He¹,

Zhang²,

Kristiansen³

et al. 2013

Express Polym. Lett.

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“…A high cross-link density characterizes the formation of microgels of composite resin. As described by Rey et al, 33 they can be divided schematically into two parts:…”

Section: Discussionmentioning

confidence: 99%

Effect of the Curing Temperature of Dental Composites evaluated with a Fluorescent Dye

Silva-Jñnior

Lizarelli

Bagnato

et al. 2018

The Journal of Contemporary Dental Practice

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Aim: With the development of the light-emitting diode (LED) to photo-activate composite resin, greater intensities could be reached without greater elevation of temperature in the mass of the composite resin and in the dental structure arisen from the irradiance in comparison to halogen equipments. This new scenario created a necessity to investigate the influence of temperature over the composite polymerization. Materials and methods:Several curing temperatures 25, 50, 75, and 100°C) were used to polymerize a composite resin (Filtek Z250, 3M ESPE) for 40 and 60 s, using the halogen equipment Gnatus Optilight Digital (halogen) and two LEDs that use a new technology to assembly the diodes: LEC 1000 and bright LEC (MM Optics) (LED 1 and LED 2 respectively). The influence of curing temperature, added by the other variables studied, was evaluated using a methodology developed and improved at IFSC/USP, in which the penetration of a fluorescent dye in the body of the photopolymerized composite resin was quantified using fluorescence spectroscopy.Results: According to the final data submitted to an analysis of variance, the presence of two groups of results could be verified: Between 0 and 25°C, both had a great percentage of the dye penetration compared with other Tcure with a variation in penetration from 69.26 ± 8.19% to 90.99 ± 3.38%. In this analysis, the effects of time and temperature were highly notable (p < 0.05) and the lesser value of dye penetration took place at 60 s of photoactivation This penetration was, in average, smaller with the Tcure of 25°C. The results showed that there was an Araraquara, 14801903, São Paulo, Brazil, e-mail: macieljr@hotmail.com interaction between the equipment and time and between time and temperature; the other group is regarding the Tcure was from 50, 75, and 100°C, despite the p = 0.05, the effect of temperature was notable. The penetration of the dye ranged from 8.87 ± 3.55 to 39.47 ± 8.9%. The effects of equipment and time were highly notable. The penetration with the time of 60 s was in average smaller. Except with the equipment LED 1, the percentages of the dye penetration were greater with the Tcure of 100°C. The smallest average was the Tcure of 50°C and 60 s of photoactivation. Conclusion:Based on the available data regarding the influence of curing temperature on the polymerization process of composite resins, was possible to concluded that small increments of heat increased the degree of conversion. We can assume that the energy supply through the generation of heat by the photopolymerizing devices can function as a heating medium for the reagent system by reducing its viscosity and increasing the mobility and agitation of its components. Clinical significance:The dentist must be aware of the effects that exist between the activation devices on the light output and their heat transmission to the composite and the tooth itself. This heat transmission might create a polymer with better characteristics.

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“…Also, it showed the highest water sorption due to hydrophilic nature, however, solubility was the lowest among them. Generally, the more densely the cross-link network forms, the more heterogeneously the structure becomes 20,24,25) . Since TEGDMA has higher flexibility than Bis-GMA, it can swell by water and fill up more water into the space within the heterogeneous network.…”

Section: Discussionmentioning

confidence: 99%

Effect of flowability on the flow rate, polymerization shrinkage, and mass change of flowable composites

Ko²,

Jeong

et al. 2015

Dental Materials Journal

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As a lining or restoration material, flowable composites are popular due to their ease in use and agreeable marginal adaptation of tooth cavity. The purpose of the present study was to evaluate various properties of flowable composites which were claimed to be of high or low flowability by the manufacturers. For the study, twelve flowable composites from six different manufacturers were used. Based on the manufacturers' claim, they were divided into two groups: high or low flowability. The products grouped in high flowability showed significantly higher (p<0.05) flow rate (flow distance), polymerization shrinkage, and microhardness (on the top surface), regardless of light-curing unit, than those grouped in low flowability. On the other hand, water sorption and solubility showed nonsignificantly different values regardless of flowability. Through the study, flow rate had low correlation with microhardness (R<0.23), polymerization shrinkage (R<0.60), and water sorption and solubility (R<0.36) regardless of light-curing unit.

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Structural heterogeneities and mechanical properties of vinyl/dimethacrylate networks synthesized by thermal free radical polymerisation

Cited by 89 publications

References 19 publications

Crosslinking effect on the deformation and fracture of monodisperse polystyrene-co-divinylbenzene particles

Crosslinking effect on the deformation and fracture of monodisperse polystyrene-co-divinylbenzene particles

Effect of the Curing Temperature of Dental Composites evaluated with a Fluorescent Dye

Effect of flowability on the flow rate, polymerization shrinkage, and mass change of flowable composites

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