scholarly journals Variability of Mechanical Properties of Collagen Membranes used in Dentistry

2018 ◽  
Vol 55 (4) ◽  
pp. 488-493
Author(s):  
Loredana Santo ◽  
Fabrizio Quadrini ◽  
Denise Bellisario ◽  
Antonella Polimeni ◽  
Anna Santarsiero
Keyword(s):  
Stress Relaxation ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Mechanical Tests ◽  
Static Behavior ◽  
Density Measurements ◽  
Dynamic Mechanical ◽  
Dependent Behavior ◽  
Order Of Magnitude ◽  
Collagen Membranes

The aim of this study is proposing a combination of measurements to assess the functional variability of collagen membranes used in Guided Bone Regeneration (GBR) and Guided Tissue Regeneration (GTR) techniques. As far as clinical applications are concerned, a proper qualification is critical when deciding, among commercially available collagen membranes, upon the most appropriate one for each specific clinical case. Two commercially available collagen membranes, namely Collprotect� and Jason�, were considered for the experimentation. After thickness and density measurements, the quasi-static behavior was studied for both membranes by means of conventional mechanical tests, i.e. tear and tensile tests, whereas their time-dependent behavior was evaluated by means of stress relaxation tests and dynamic mechanical analysis. Collagen membranes showed an elevated among samples variability. The variability within the same kind of membrane is of the same order of magnitude of the between membrane kinds variability. All the membranes showed strong time dependence both in stress relaxation and in dynamic mechanical tests. This fact should be taken under consideration for the membrane final application.

An Approach to Characterize Nonlinear Viscoelastic Material Behavior Using Dynamic Mechanical Tests and Analyses

1999 ◽  
Vol 66 (4) ◽  
pp. 872-878 ◽  
Author(s):  
H. J. Golden ◽  
T. W. Strganac ◽  
R. A. Schapery
Keyword(s):  
Viscoelastic Model ◽  
Dynamic Test ◽  
Mechanical Analysis ◽  
Mechanical Tests ◽  
Material Behavior ◽  
Dynamic Mechanical ◽  
Nonlinear Characterization ◽  
Nonlinear Viscoelastic ◽  
Linear Viscoelastic ◽  
Nonlinear Viscoelastic Model

Linear viscoelastic properties may be rapidly identified using dynamic mechanical analysis methods, yet these traditional methods do not properly identify nonlinear viscoelastic response. Herein, dynamic mechanical methodologies are extended to provide an approach for nonlinear characterization. The proposed method is based on Schapery's nonlinear viscoelastic model extended to dynamic mechanical theory. The oscillatory loading during a dynamic test is addressed within the nonlinear viscoelastic model. An experimental protocol is established. Analyses and experiments are performed for the characterization of thin-film polyethylene to validate the approach.

scholarly journals Biodegradable and Toughened Composite of Poly(Propylene Carbonate)/Thermoplastic Polyurethane (PPC/TPU): Effect of Hydrogen Bonding

2018 ◽  
Vol 19 (7) ◽  
pp. 2032 ◽  
Author(s):  
Dongmei Han ◽  
Guiji Chen ◽  
Min Xiao ◽  
Shuanjin Wang ◽  
Shou Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Propylene Carbonate ◽  
Thermoplastic Polyurethane ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Dynamic Mechanical ◽  
Brittle Ductile Transition ◽  
Poly Propylene

The blends of Poly(propylene carbonate) (PPC) and polyester-based thermoplastic polyurethane (TPU) were melt compounded in an internal mixer. The compatibility, thermal behaviors, mechanical properties and toughening mechanism of the blends were investigated using Fourier transform infrared spectra (FTIR), tensile tests, impact tests, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and dynamic mechanical analysis technologies. FTIR and SEM examination reveal strong interfacial adhesion between PPC matrix and suspended TPU particles. Dynamic mechanical analyzer (DMA) characterize the glass transition temperature, secondary motion and low temperature properties. By the incorporation of TPU, the thermal stabilities are greatly enhanced and the mechanical properties are obviously improved for the PPC/TPU blends. Moreover, PPC/TPU blends exhibit a brittle-ductile transition with the addition of 20 wt % TPU. It is considered that the enhanced toughness results in the shear yielding occurred in both PPC matrix and TPU particles of the blends.

Fabrication and Characterization of Sisal/Glass and Polypropylene Hybrid Composites

2007 ◽  
Vol 29-30 ◽  
pp. 271-274
Author(s):  
S.K. Samal ◽  
S. Mohanty ◽  
S.K. Nayak
Keyword(s):  
Storage Modulus ◽  
Mechanical Performance ◽  
Hybrid Composites ◽  
Loss Modulus ◽  
Analysis Data ◽  
Mechanical Analysis ◽  
Mechanical Tests ◽  
Sisal Fiber ◽  
Tensile Fracture ◽  
Dynamic Mechanical

The present work summarizes an experimental study on the dynamic mechanical behaviour of sisal – glass fiber reinforced PP composites (SGRP). Variation in mechanical strength, storage modulus (E’), loss modulus (E’’) and damping parameters (tan δ) with the addition of fibers and MAPP were investigated. Mechanical tests revealed an increase in the tensile, flexural and impact strength in the SFRP composites with an increase in the fiber loading from 10% to 30%. Further the SGRP composites prepared using 15 wt% of glass and 15 wt % of sisal fiber, exhibited improved mechanical performance as compared with the virgin matrix as well as 30% SFRP composites. The fiber matrix morphology of the interface region in the composites was examined employing SEM analysis of the tensile fracture specimens. Thermal stability in the composites was studied using TGA/DTG thermo grams. Dynamic mechanical analysis data showed an increase in the storage modulus of the treated composite. The tanδ spectra presented a strong influence of fiber content and coupling agent on the α and γ relaxation process of PP. FTIR spectra of the treated and untreated sisal fibers was also studied to ascertain the existence of the type of interfacial bonds.

scholarly journals Poly(ε-Caprolactone)/Brewers’ Spent Grain Composites—The Impact of Filler Treatment on the Mechanical Performance

2020 ◽  
Vol 4 (4) ◽  
pp. 167
Author(s):  
Aleksander Hejna
Keyword(s):  
Chemical Structure ◽  
Mechanical Performance ◽  
Natural Fiber ◽  
Reactive Extrusion ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Mechanical Tests ◽  
Interface Surface ◽  
Spent Grain ◽  
The Impact

Waste lignocellulose materials, such as brewers’ spent grain, can be considered very promising sources of fillers for the manufacturing of natural fiber composites. Nevertheless, due to the chemical structure differences between polymer matrices and brewers’ spent grain, filler treatment should be included. The presented work aimed to investigate the impact of fillers’ reactive extrusion on the chemical structure and the poly(ε-caprolactone)/brewers’ spent grain composites’ mechanical performance. The chemical structure was analyzed by Fourier-transform infrared spectroscopy, while the mechanical performance of composites was assessed by static tensile tests and dynamic mechanical analysis. Depending on the filler pretreatment, composites with different mechanical properties were obtained. Nevertheless, the increase in pretreatment temperature resulted in the increased interface surface area of filler, which enhanced composites’ toughness. As a result, composites were able to withstand a higher amount of stress before failure. The mechanical tests also indicated a drop in the adhesion factor, pointing to enhanced interfacial interactions for higher pretreatment temperatures. The presented work showed that reactive extrusion could be considered an auspicious method for lignocellulose filler modification, which could be tailored to obtain composites with desired properties.

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