A study of shrinkage stress reduction and mechanical properties of nanogel-modified resin systems

The aim of this study was to evaluate the effect of camphorquinone concentration in physical-mechanical properties of experimental flowable composites in order to find the concentration that results in maximum conversion, balanced mechanical strength, and minimum shrinkage stress. Model composites based on BISGMA/TEGDMA with 70% wt filler loading were prepared containing different concentrations of camphorquinone (CQ) on resin matrix (0.25%, 0.50%, 1%, 1.50%, and 2% by weight). Degree of conversion was determined by FTIR. Surface hardness was assessed before and after 24 h ethanol storage and softening rate was determined. Depth of cure was determined by Knoop hardness evaluation at different depths. Color was assessed by reflectance spectrophotometer, employing the CIE-Lab system. Flexural strength and elastic modulus were determined by a three-point bending test. Shrinkage stress was determined in a Universal Testing Machine in a high compliance system. Data were submitted to ANOVA and Tukey’s test (α = 0.05). The increase in CQ concentration caused a significant increase on flexural strength and luminosity of composites. Surface hardness was not affected by the concentration of CQ. Composite containing 0.25% wt CQ showed lower elastic modulus and shrinkage stress when compared to others. Depth of cure was 3 mm for composite containing 1% CQ and 2 mm for the other tested composites. Degree of conversion was inversely correlated with softening rate and directly correlated with elastic modulus and shrinkage stress. In conclusion, CQ concentration affects polymerization characteristics and mechanical strength of composites. The concentration of CQ in flowable composite for optimized polymerization and properties was 1% wt of the resin matrix, which allows adequate balance among degree of conversion, depth of cure, mechanical properties, and color characteristics of these materials.

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Study of Hybrid Nanoparticles Modified Epoxy Resin Used in Filament Winding Composite

Materials ◽

10.3390/ma12233853 ◽

2019 ◽

Vol 12 (23) ◽

pp. 3853 ◽

Cited By ~ 3

Author(s):

Chengrui Di ◽

Junwei Yu ◽

Baoming Wang ◽

Alan Kin Tak Lau ◽

Bo Zhu ◽

...

Keyword(s):

Mechanical Properties ◽

Particle Size ◽

Tensile Strength ◽

Carbon Fiber ◽

Filament Winding ◽

Hybrid Nanoparticles ◽

Resin System ◽

Modified Epoxy ◽

Wound Composite ◽

Modified Resin

Hybrid nanoparticles modified bisphenol A type epoxy/acid anhydride resin system applicable for filament winding forming process was studied using elastic core-shell rubber (CSR) nanoparticles with a large particle size (nearly 100 nm) and rigid nano-SiO2 particles with a small particle size (about 16 nm). The formulation, process properties, mechanical properties, thermal properties and microstructure of modified resin and its wound composite were studied. The results suggested that at the content of 10 phr CSR and 2 phr nano-SiO2, the resin system achieved optimum comprehensive performance. The viscosity of modified resin system was nearly 1000 mPa·s at 25 °C and service life was over 6 h. The resin tensile strength and modulus were 89 MPa and 3.5 GPa, while flexural strength and modulus reached 128 MPa and 3.2 GPa, respectively. The impact strength was 26.6 kJ·m−2, and the glass transition temperature (Tg) reached 145.9 °C. Modified epoxy resin enhanced the mechanical properties of carbon fiber reinforced wound composite. The tensile strength, tensile modulus and interlaminar shear strength were enhanced by 14.0%, 4.56% and 18.9%, respectively, compared with a composite based on unmodified resin. The above test results and scanning electron microscopy (SEM) analysis suggest that the hybrid nanoparticles modified resin system was suitable for carbon fiber wet filament winding products.

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Evaluation of mechanical properties and shrinkage stress of thiol-ene-methacrylate dental composites with synthesized fluorinated allyl ether

Journal of the Mechanical Behavior of Biomedical Materials ◽

10.1016/j.jmbbm.2019.03.027 ◽

2019 ◽

Vol 95 ◽

pp. 53-59 ◽

Cited By ~ 2

Author(s):

Wen Fu ◽

Li Wang ◽

Jingwei He

Keyword(s):

Mechanical Properties ◽

Dental Composites ◽

Allyl Ether ◽

Shrinkage Stress

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Shrinkage stress and mechanical properties of photoactivated composite resin using the argon ion laser

Applied Physics B ◽

10.1007/s00340-009-3366-6 ◽

2009 ◽

Vol 96 (1) ◽

pp. 79-84 ◽

Cited By ~ 5

Author(s):

C. S. Delfino ◽

C. S. C. Pfeifer ◽

R. R. Braga ◽

M. N. Youssef ◽

M. L. Turbino

Keyword(s):

Mechanical Properties ◽

Composite Resin ◽

Shrinkage Stress ◽

Argon Ion Laser ◽

Ion Laser ◽

Argon Ion

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Reduction of Residual Quenching Stresses in 2A14 Aluminum Alloy Tapered Cylinder Forgings via a Novel Cold Bulging Process

Metals ◽

10.3390/met11050717 ◽

2021 ◽

Vol 11 (5) ◽

pp. 717

Author(s):

Bingxiang Wang ◽

Youping Yi ◽

Shiquan Huang ◽

Hailin He

Keyword(s):

Mechanical Properties ◽

Finite Element Method ◽

Residual Stresses ◽

Stress Reduction ◽

Fem Simulation ◽

Hole Drilling ◽

Fem Simulations ◽

Physical Experiments ◽

Transmission Electron ◽

Precipitated Phases

This study combined finite element method (FEM) simulations and physical experiments to develop a novel cold bulging process, with the aim of studying and mitigating the quenching residual stresses in 2A14 tapered cylinder forgings. The samples underwent cold bulging at different ratios (0–4.0%) to evaluate the residual stress reduction performance (via the hole-drilling strain-gauge method) and the improvements in their mechanical properties. The FEM simulation and experimental results revealed that our proposed cold bulging process reduced the quenching residual stresses by up to 85–87%. The density and uniformity of the precipitated phases increased along with the extent of cold bulging, as confirmed by transmission electron microscope (TEM) observations. Furthermore, compared to the unprocessed samples, the tensile and yield strengths, and elongation of the samples with 3% cold bulging were significantly enhanced (65 MPa, 55 MPa, and 1.7%, respectively).

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Influence of Modified Epoxy Resins on Peroxide Curing, Mechanical Properties and Adhesion of SBR, NBR and XNBR to Silver Wires. Part I: Application of Monoperoxy Derivative of Epoxy Resin (PO)

Materials ◽

10.3390/ma14051320 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1320

Author(s):

Joanna Chudzik ◽

Dariusz M. Bieliński ◽

Michael Bratychak ◽

Yuriy Demchuk ◽

Olena Astakhova ◽

...

Keyword(s):

Mechanical Properties ◽

Epoxy Resin ◽

Styrene Butadiene Rubber ◽

Dicumyl Peroxide ◽

Butadiene Rubber ◽

Acrylonitrile Butadiene Rubber ◽

Peroxide Curing ◽

Styrene Butadiene ◽

Modified Epoxy ◽

Modified Resin

The research was aimed at checking the effect of monoperoxy derivative of epoxy resin (PO) on the possibility of rubber crosslinking and a subsequent adhesion of the modified rubber to silver wires. Three of the commonly industrially used rubbers were selected for the study: styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR) and carboxylated acrylonitrile-butadiene rubber (XNBR), together with the popular, commercially available Epidian 6 epoxy resin, subjected to the functionalization. An improvement in the adhesion of rubbers to silver wires was observed when using the modified resin. In some cases, an improvement in the mechanical properties of the rubber was observed, especially when the resin was used for crosslinking together with dicumyl peroxide (DCP). Crosslinking synergy between dicumyl peroxide and the modified resin could be observed especially in the case of PO applied for peroxide curing of SBR and NBR.

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A Comparative Study of the Mechanical Properties of Selected Dental Composites with a Dual-Curing System with Light-Curing Composites

Coatings ◽

10.3390/coatings11101255 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1255

Author(s):

Monika Domarecka ◽

Agata Szczesio-Wlodarczyk ◽

Michał Krasowski ◽

Magdalena Fronczek ◽

Tomasz Gozdek ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Flexural Strength ◽

Comparative Study ◽

Wide Spectrum ◽

Shrinkage Stress ◽

Three Point Bending ◽

Light Curing ◽

Dual Curing ◽

Diametral Tensile Strength

Dual-curing composites have a wide spectrum of use in practice (rebuilding, reconstruction, and luting). The characterization of this type of material and comparative study of selected mechanical properties with light-cured materials were carried out for this paper. In this study, we used six materials with a dual-cure system—Bulk EZ, Fill-Up!, StarFill 2B, Rebilda DC, MultiCore Flow, Activa Bioactive-Restorative—and three light-cured materials—Filtek Bulk Fill Posterior, Charisma Classic, and G-aenial Universal Flo. The materials were conditioned for 24 h in water at 37 °C before testing. Selected material properties were determined: three-point bending flexural strength, diametral tensile strength, hardness, microhardness, and shrinkage stress. The highest three-point bending flexural strength (TPB) was 137.0 MPa (G-aenial Universal Flo), while the lowest amounted to 86.5 MPa (Activa Bioactive). The diametral tensile strength (DTS) values were in a range from 39.2 MPa (Rebilda DC) to 54.1 MPa (Charisma Classic). The lowest hardness (HV) value of 26 was obtained by the Activa Bioactive material, while the highest values were recorded for Filtek Bulk Fill Posterior and Charisma Classic-53. The shrinkage stress of the tested materials ranged from 6.3 MPa (Charisma Classic) to 13.2 MPa (G-aenial Universal Flo). Dual-curing composites were found to have similar properties to light-cured composites.

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