Comparative study on the mechanical and fracture properties of acrylic bone cements prepared with monomers containing amine groups (original) (raw)
Related papers
2008
This study investigated experimentally the fracture properties, i.e., the fatigue strength, the resistance to crack propagation and the fracture toughness, of an acrylic bone cement (Cemex RX). The mean endurance limit was determined following the staircase method. The endurance limit was estimated at 9.2 MPa. The fatigue crack propagation rate was measured according to the ASTM E647 standard. The equation of the line fitting the crack growth per cycle (da/dN) versus the stress-intensity factor range (∆K), in a log–log graph, was used to calculate the empirical constants of Paris’ law for the selected bone cement: da/dN (m/cycle) = 3.56·10·∆K (MPa·m). This power-law relationship described well (R = 0.96) the growth rate in the stable crack growth region, i.e., in the mid ∆K range. The fracture toughness KIC of the bone cement was determined according to the ASTM E399 standard. The KIC mean value was 1.38 MPa·m. These experimental results provide the set of necessary inputs for numer...
Mechanical properties of oligomer-modified acrylic bone cement
Biomaterials, 2003
The aim of this study was to determine the mechanical properties of acrylic bone cement modified with an experimental oligomer filler, based on an amino acid of trans-4-hydroxy-L-proline synthesized in the laboratory. The test specimens were tested either dry, or after being stored in distilled water or in simulated body fluid (SBF) for 1 week and then tested in distilled water. The three-point bending test was used to measure the flexural strength and flexural modulus of the cement, and the compression tests were used to measure the compression strength and modulus. One test specimen from each group was examined under a scanning electron microscope (SEM) to determine the nature of the oligomer filler in the polymethylmethacrylate-polymethylacrylate copolymerbased (PMMA-PMA/PMMA) polymer blend. In dry conditions, the flexural strength of the test specimens tested in air was 66 MPa; and the compression strength was 93 GPa (po0:001) for the plain bone cement. For the test specimens including 20 wt% of oligomer filler, the flexural strength was 37 MPa; and the compression strength was 102 MPa ðpo0:001Þ in dry conditions. The storage in wet conditions (in distilled water and the SBF) decreased the flexural strength of the test specimens with 20 wt% of oligomer filler ðpo0:001Þ by 60% and the flexural modulus by 44% compared to the plain bone cement specimens stored in the same conditions. The reduction in compression strength in wet conditions was 32%, and that of the compression modulus was 30% ðpo0:001Þ: No significant differences were found between test specimens stored in distilled water or SBF (ANOVA, po0:001). In the SEM examinations, random voids were observed in the oligomer-PMMA-PMA/PMMA polymer blend after water or SBF storage. The results suggest that both water and SBF storage decrease the mechanical properties of the PMMA-PMA/PMMA bone cement modified with oligomer, while at the same time, there was porous formation in the bone cement structure. r (M.A. Puska).
Journal of Materials Science-materials in Medicine, 1999
Fracture and mechanical characterization of bone composite composed of polymethylmethacrylate and hydroxyapatite (HA) at different contents was carried out. Hydroxyapatite is added in order to improve cement biocompatibility, but it is expected that it also affects mechanical properties. Specimens were either stored in air at 37°C for 120 h or in physiological solution (PhS-37), in order to establish the influence of storage conditions upon mechanical behavior. One set of specimens was also postcured at 120°C for 4 h to take into account the influence of free monomer. Fracture experiments revealed some non-linearity in load–displacement records and differences in trends between initiation and propagation values of the fracture surface energies. The trends in the data shows that HA acts as a rigid filler enhancing fracture resistance, flexural modules and yield stress, up to a certain content. Beyond the latter limit, properties suffer a deterioration because the addition of HA also affects the cement porosity. Absorbed water acts as plasticizer leading to a decrease in mechanical properties. The highest propagation strain energies were exhibited by materials aged in PhS-37. ©1999 Kluwer Academic Publishers
Effects of ingredients on thermal and mechanical properties of acrylic bone cements
Journal of Applied Polymer Science, 2009
There is a very delicate relation between the amounts of all the ingredients present in the cement composition and the properties of the product. In this study, homogeneous poly(methyl methacrylate) (PMMA) microspheres were prepared by suspension polymerization technique, and used in cement formulations. Various acrylic cements with different compositions were prepared by using PMMA microspheres, methyl methacrylate (MMA) monomer, radiopaque agent of barium sulfate (BaSO 4 ), inorganic particles of hydroxyapatite (HA), initiator and chain stopping agent of 1dodecyl mercaptan (DDM). The effects of these additives on mechanical and thermal properties of the resultant cements were examined. Addition of 8% HA relative to the solid parts caused an increase in both tensile and compressive strengths from 20.40 to 25.20 MPa, and from 84.04 to 89.57 MPa, respectively, while curing temperature was decreased about 3 degrees. Chain stopping agent of DDM caused a sharp decrease about 30 degrees in the curing temperature. Radiopaque agent of barium sulfate caused inverse effect on mechanical and thermal properties.
Fracture properties of an acrylic bone cement
Acta of bioengineering and biomechanics / Wrocław University of Technology, 2008
This study investigated experimentally the fracture properties, i.e., the fatigue strength, the resistance to crack propagation and the fracture toughness, of an acrylic bone cement (Cemex RX). The mean endurance limit was determined following the staircase method. The endurance limit was estimated at 9.2 MPa. The fatigue crack propagation rate was measured according to the ASTM E647 standard. The equation of the line fitting the crack growth per cycle (da/dN) versus the stress-intensity factor range (∆K), in a log-log graph, was used to calculate the empirical constants of Paris' law for the selected bone cement: da/dN (m/cycle) = 3.56·10 -7 ·∆K (MPa·m 1/2 ) 5.79 . This power-law relationship described well (R 2 = 0.96) the growth rate in the stable crack growth region, i.e., in the mid ∆K range. The fracture toughness K IC of the bone cement was determined according to the ASTM E399 standard. The K IC mean value was 1.38 MPa·m ½ . These experimental results provide the set of necessary inputs for numerical studies aimed to investigate the damage accumulation process in the mantle fixing cemented prostheses.
Influence of mixing techniques on the physical properties of acrylic bone cement
Biomaterials, 2001
Palacos R bone cement was prepared using three commercially available mixing techniques, "rst generation, second generation and third generation, to determine the mechanical properties and porosity contents of the bone cement. The compressive strengths, bending strengths and #exural moduli were expressed as a function of void content. The volume of pores within the cement structure was found to be a contributing factor to the physical properties of acrylic bone cement. The lower the volume of voids in the cement the better the compressive and #exural properties, hence stronger bone cement. It was found that the best results were obtained from cement that had been mixed using the Mitab Optivac or Summit HiVac Syringe systems at a reduced pressure level of between !72 and !86 kPa below atmospheric pressure, resulting in cement of porosity 1.44}3.17%; compressive strength 74}81 MPa; #exural modulus 2.54}2.60 GPa; and #exural strength 65}73 MPa.
Biomaterials, 1996
The effect of the size and the size distribution of poly(methyl methacrylate) (PMMA) beads on the classical kinetic parameters, peak temperature and setting time, for acrylic bone cement formulations prepared with PMMA particles in the range 10-60~m of average diameter and a relatively wide size distribution is analysed. In addition, the combined effects of the concentration of the free radical initiator benzoyl peroxide and the activator N,N-dimethyl-4-toluidine for the different particle sizes are studied and compared with those of commercially available formulations like CMW or Rostal. The results obtained indicate that the use of PMMA particles with average diameter of 50-60pm, and a relatively wide size distribution (lO-140pm diameter), significantly changes the curing parameters (peak temperature and setting time) of the cement formulations in comparison with the classical behaviour of the commercial systems CMW and Rostal, without any noticeable loss in the mechanical properties, such as tensile strength, elastic moduli, compressive strength and plastic strain.
Journal of Applied Polymer Science, 2012
In this work, a thermal and a dynamic mechanical study of new formulations self-curing acrylic bone cements is reported. The basic formulation of poly(methylmethacrylate) (PMMA)-based acrylic bone cements has been modified with biodegradable polyesters such as poly(L-lactic acid), poly(b-hydroxybutyrate), and different kinds of thermoplastic starches. Differential scanning calorimetry (DSC) (dynamic and isothermal conditions), thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), and scanning electron microscopy (SEM) were used to determine the influence of the biodegradable polymer in the behavior of the biomedical formulations. DSC assay revealed a strong dependence of the polymerization enthalpy (DH cur) with increasing solid : liquid ratio and a low influence of the nature of the added biodegradable polymer on glass transition. TGA analysis showed the different mechanism of PMMA-biodegradable polymer interaction depending on the solubilization of the added polymer in methylmethacrylate monomer during curing. DMTA showed the reinforcing capacity of segregated phases of the polymer included in the cement. The solubilization of aliphatic polyesters in the resulting PMMA polymerized phase led to a drop in mechanical stiffness observed from storage modulus (E 0) profiles. Moreover, tan d shifts to higher temperatures (4-7 C) during a second scan, confirming the presence of residual monomer content. V
Journal of Applied Polymer Science, 2014
The effect of the particle size of poly(methyl methacrylate) (PMMA) and the incorporation of chitosan (CH) on the mechanical and thermal properties and the biocompatibility of acrylic bone cements were investigated. Three groups of bone cements were prepared with different PMMA particles. Groups 1 (BC1) and 2 (BC2) contained ground and sieved PMMA with particle sizes in the ranges 50-150 lm and 1-50 lm, and group 3 (BC3) contained synthesized PMMA microspheres with a size of about 1 lm. The mechanical properties of the three groups were similar, but their curing properties were significantly affected. The presence of CH improved the mechanical and thermal properties. For the BC1 group, the compressive strength increased more than 10 MPa, and the curing temperature decreased 12 . The cement having the optimum properties (BC1) was applied to rats, where it enhanced the bone bonding ability, and bioactivity was observed.