Correlation between degree of conversion, filler concentration and mechanical properties of posterior composite resins

1990 ◽  
Vol 17 (5) ◽  
pp. 487-494 ◽  
Author(s):  
K.-H. CHUNG ◽  
E. H. GREENER
Keyword(s):  
Mechanical Properties ◽  
Composite Resins ◽  
Degree Of Conversion ◽  
Filler Concentration

scholarly journals Hydrophobic composite resins using a novel allylic urethane monomer as additive

2019 ◽  
Vol 63 (4) ◽  
Author(s):  
José Abraham González-López ◽  
Alma Antonia Pérez-Mondragón ◽  
Carlos E. Cuevas-Suárez ◽  
Juan Coreño Alonso ◽  
Nayely Trejo-Carbajal ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Organic Matrix ◽  
Polymerization Kinetics ◽  
Polymerization Rate ◽  
Composite Resins ◽  
Degree Of Conversion ◽  
Volumetric Shrinkage ◽  
Matrix System ◽  
Control Material ◽  
Hydrophobic Behavior

The purpose of this study is to report the formulation of photopolymerizable composites resins with hydrophobic behavior using a new urethane monomer (ETODC) as additive. The ETODC monomer was used together with Bis-GMA and TEGDMA to formulate a new organic matrix system. Mechanical and hydrophobic behavior were studied, also volumetric shrinkage, viscosity, polymerization kinetics and cytotoxicity were analyzed. Results were compared with a control resin prepared with Bis-GMA and TEGDMA. The results show that mechanical properties and volumetric shrinkage did not present statistical differences between the studied groups. When compared with the control material, the experimental resin formulated with the ETODC monomer showed higher hydrophobic behavior and higher values of degree of conversion and polymerization rate.

Light curing and ratio of glass/fumed silica fillers on degree of conversion and mechanical properties of experimental composite resins

2018 ◽  
Vol 136 (7) ◽  
pp. 47008
Author(s):  
A. F. Silva Prezotto ◽  
D. B. Silva ◽  
R. P. Vitti ◽  
M. A. C. Sinhoreti ◽  
W. C. Brandt
Keyword(s):  
Mechanical Properties ◽  
Fumed Silica ◽  
Composite Resins ◽  
Degree Of Conversion ◽  
Silica Fillers ◽  
Light Curing

Expanded vermiculite-filled flexible polymer composites

2021 ◽  
pp. 009524432110290
Author(s):  
Mukaddes Sevval Cetin ◽  
Ozan Toprakci ◽  
Omer Suat Taskin ◽  
Abdullah Aksu ◽  
Hatice Aylin Karahan Toprakci
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Contact Angle ◽  
Polymer Composites ◽  
Flame Retardancy ◽  
Composite Films ◽  
Filler Concentration ◽  
High Shear ◽  
Flexible Polymer ◽  
Shear Mixing

This study focuses on the fabrication and characterization of vermiculite-filled flexible polymer composites. Exfoliated vermiculite was incorporated into triblock thermoplastic elastomer copolymer, styrene- b-(ethylene- co-butylene)- b-styrene (SEBS), at various levels from 1 to 15 wt% by a high shear mixer. The composite films were obtained by the combination of solvent casting and compression molding. The morphological, structural, thermal, and mechanical properties and contact angle of the composites were determined. Some micro-morphological differences were observed between the samples and the difference was assumed to be caused by high shear mixing and filler concentration. High shear mixing was found effective in terms of the detachment of vermiculite layers at all concentrations. However, at low filler loading, that behavior was more obvious. At 1 wt% filler concentration, mechanical properties increased that was probably caused by good filler-matrix interaction stemmed from smaller particle size. At higher vermiculite concentrations, fillers found to show agglomerations that led to a decrease in mechanical strength and strain at break. Elastic and secant modulus showed an increasing trend. Contact angle measurements were carried out to determine the oleophilic character of the samples. An increase in the vermiculite content resulted in higher oleophilic character and the lowest contact angle was obtained at 15 wt% VMT loading. In addition to these, thermal stability, thermal dimensional stability and flame retardancy were improved by the incorporation of VMT. 15 wt% vermiculite-filled sample showed the best performance in terms of thermal stability and flame retardancy.

Effect of Wood Filler Concentration on Physical and Mechanical Properties of PLA-Based Composites

2021 ◽  
Vol 887 ◽  
pp. 110-115
Author(s):  
G.A. Sabirova ◽  
R.R. Safin ◽  
N.R. Galyavetdinov
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Composite Materials ◽  
Impact Strength ◽  
Wood Flour ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Filler Concentration ◽  
High Concentration

This paper presents the findings of experimental studies of the physical and mechanical properties of wood-filled composites based on polylactide (PLA) and vegetable filler in the form of wood flour (WF) thermally modified at 200-240 °C. It also reveals the dependence of the tensile strength, impact strength, bending elastic modulus, and density of composites on the amount of wood filler and the temperature of its thermal pre-modification. We established that an increase in the concentration of the introduced filler and the degree of its heat treatment results in a decrease of the tensile strength, impact strength and density of composite materials, while with a lower binder content, thermal modification at 200 °C has a positive effect on bending elastic modulus. We also found that 40 % content of a wood filler heated to 200 °C is sufficient to maintain relatively high physical and mechanical properties of composite materials. With a higher content of a wood filler, the cost can be reduced but the quality of products made of this material may significantly deteriorate. However, depending on the application and the life cycle of this product, it is possible to develop a formulation that includes a high concentration of filler.

The effect of preheating of nano-filler composite resins on their degree of conversion and microfiltration in dental fillings

2022 ◽  
Author(s):  
A. Catalán ◽  
A. Martínez ◽  
C. Muñoz ◽  
C. Medina ◽  
T. Marzialetti ◽  
...  
Keyword(s):  
Composite Resins ◽  
Degree Of Conversion ◽  
Dental Fillings

scholarly journals Deterioration of Mechanical Properties of Composite Resins

1995 ◽  
Vol 14 (1) ◽  
pp. 78-83,104 ◽  
Author(s):  
Hiroyuki ARIKAWA ◽  
Hiroyuki KUWAHATA ◽  
Hideo SEKI ◽  
Takahito KANIE ◽  
Koichi FUJII ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Resins

Physical–mechanical evaluation of a microhybrid and a nanofilled composite light activated by quartz-halogen tungsten and light-emitting diode

2018 ◽  
Vol 53 (7) ◽  
pp. 981-990
Author(s):  
Fernanda P Ritto ◽  
Eduardo Moreira da Silva ◽  
Hélio Rodrigues Sampaio-Filho ◽  
Raimundo A Lacerda ◽  
Márcio AP Borges ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Nuclear Magnetic Resonance ◽  
Light Emitting Diode ◽  
Degree Of Conversion ◽  
Dental Composite ◽  
Polymerization Shrinkage ◽  
Light Emitting ◽  
Scanning Electron

The aim of this study was to characterize organic and disperse phase of a microhybrid (Mh – Filtek Z250) and a nanofilled (Nf – Filtek Z350) dental composite and analyze the influence of two LCUs (QHT-quartz-halogen tungsten and LED – light-emitting diode) on its physical–mechanical properties (degree of conversion, polymerization shrinkage, Vickers hardness and diametral tensile strength). Surface morphology was studied by scanning electron microscopy. The disperse phase content was measured using thermogravimetric analysis (TGA) and the organic fractions were qualitatively analyzed by nuclear magnetic resonance spectroscopy. Physical–mechanical properties were analyzed varying dental composite and LCU: Mh-QHT, Nf-QHT, Mh-LED and Nf-LED. The degree of conversion was evaluated using Raman spectrophotometry and polymerization shrinkage was measured by water picnometry. Mechanical behavior was analyzed by Vickers microhardness and diametral tensile testing. Scanning electron microscopy analysis showed similar microstructure of the materials mainly composed with different-sized particles dispersed within methacrylate matrix. Thermogravimetric analysis shows 80.13% of inorganic fraction for microhybrid composite and 75.29% for nanofilled. Nuclear magnetic resonance analysis showed similar organic structure for composites and did not show the presence of the monomer TEGDMA. Different light sources did not influence the tested properties, but considering different composites, nanofilled showed the highest degree of conversion (Gr 2:77%, Gr 4: 79.4%). The study shows that when the optimum radiant exposure (24 J/cm2) was used for polymerization of composites, regardless of the polymerization source, the properties of these resin materials showed satisfactory and similar results in relation to the conversion of polymers, polymerization shrinkage and mechanical behavior.

Evaluation of the mechanical properties and degree of conversion of 3D printed splint material

2021 ◽  
Vol 115 ◽  
pp. 104254
Author(s):  
Leila Perea-Lowery ◽  
Mona Gibreel ◽  
Pekka K. Vallittu ◽  
Lippo Lassila
Keyword(s):  
Mechanical Properties ◽  
Degree Of Conversion ◽  
3D Printed

scholarly journals Improved Fracture Toughness and Conversion Degree of Resin-Based Dental Composites after Modification with Liquid Rubber

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2704
Author(s):  
Krzysztof Pałka ◽  
Joanna Kleczewska ◽  
Emil Sasimowski ◽  
Anna Belcarz ◽  
Agata Przekora
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Dental Materials ◽  
Degree Of Conversion ◽  
Dental Composites ◽  
Conversion Degree ◽  
Matrix Resin ◽  
Ceramic Filler ◽  
Liquid Rubber ◽  
The Matrix

There are many methods widely applied in the engineering of biomaterials to improve the mechanical properties of the dental composites. The aim of this study was to assess the effect of modification of dental composites with liquid rubber on their mechanical properties, degree of conversion, viscosity, and cytotoxicity. Both flow and packable composite consisted of a mixture of Bis-GMA, TEGDMA, UDMA, and EBADMA resins reinforced with 60 and 78 wt.% ceramic filler, respectively. It was demonstrated that liquid rubber addition significantly increased the fracture toughness by 9% for flow type and 8% for condensable composite. The influence of liquid rubber on flexural strength was not statistically significant. The addition of the toughening agent significantly reduced Young’s modulus by 7% and 9%, respectively, while increasing deformation at breakage. Scanning electron microscopy (SEM) observations allowed to determine the mechanisms of toughening the composites reinforced with ceramic particles. These mechanisms included bridging the crack edges, blocking the crack tip by particles and dissipation of fracture energy by deflection of the cracks on larger particles. The degree of conversion increased after modification, mainly due to a decrease in the matrix resin viscosity. It was also shown that all dental materials were nontoxic according to ISO 10993-5, indicating that modified materials have great potential for commercialization and clinical applications.

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