The Effects of Gamma Irradiation on Medical Grade Poly(Methyl Methacrylate)

Barton, S.K.; Foot, P.J.S.; Tate, Philip C. Miller; Kishi, Mariko; Ghatora, Baljit

doi:10.1177/096739111302100101

Cited by 5 publications

(2 citation statements)

References 25 publications

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“…Radiolytic processes are involved in the sterilization of some polymers before implantation (Barton et al, 2013). Results obtained on PMMA unambiguously show the decrease of molar mass, which is ascribed to the mechanisms shown in Scheme 7.11.…”

Section: Chemical Ageing By Radiolysismentioning

confidence: 78%

Polymethacrylates

Pomes

Emmanuel

Nguyen

2019

Materials for Biomedical Engineering

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In the 1950s, composite restorations were made from PMMA. Significant polymerization induced volume shrinkage and heat release as well as the release of methyl methacrylate monomers resulting in marginal discoloration, pulp reactions, and secondary caries. In 1956, Bowen tried to reduce shrinkage by using a bigger monomer: the bisphenol A surrounded by two glycidyl groups. However, moisture tended to inhibit polymerization. Bisphenol A glycidyl methacrylate (Bis-GMA, Fig. 7.2) was obtained by substituting end groups with methacrylate functions and offered an excellent solution to the problem (Bowen, 1962; Soderholm and Mariotti, 1999). Bis-GMA has several advantages compared to PMMA, such as lower volatility, lower diffusion in dental tissues, and lower polymerization shrinkage because of its larger size, which explains its success. In addition, its tetrafunctional structure (i.e., two double bonds) makes it possible to obtain a crosslink network with better mechanical and physical properties. However, Bis-GMA shows a high viscosity (1200 Pa s) (Barszczewska-Rybarek, 2009) because of its large size, and rigidity due to the two aromatic rings and especially its hydroxyl groups creating strong hydrogen intermolecular bonds between them which significantly reduces the mobility and make the molecule more hydrophilic. As it will be seen later, this involves a low conversion degree (DC)-39% in the case of photopolymerization and a limited incorporation of fillers as well as difficulty to handle the material (Sideridou et al., 2002). Consequently, Bis-GMA is always associated with minor monomers such as triethylene glycol dimethacrylate-TEGDMA, with a viscosity of 0.011 Pa s FIGURE 7.1 Removable total denture.

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Section: Chemical Ageing By Radiolysismentioning

confidence: 78%

Polymethacrylates

Pomes

Emmanuel

Nguyen

2019

Materials for Biomedical Engineering

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“…Several studies analyzing the effects of different sterilization methods on the resulting properties of PMMA have already been conducted. [9][10][11][12][13][14] However, medical devices usually undergo a cleaning step preceding sterilization, [15] which could influence the material, as this process usually involves temperature, pressure, and an aqueous solution of washing agent. [16] It is known that polymers in general, and thus also PMMA, exhibit temperature-, [17] pressure- [18] and moisture-dependent [19,20] properties.…”

Section: Introductionmentioning

confidence: 99%

The Effects of Washing and Formaldehyde Sterilization on the Mechanical Performance of Poly(methyl Methacrylate) (PMMA) Parts Produced by Material Extrusion‐Based Additive Manufacturing or Material Jetting

et al. 2022

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Nowadays, personalized medical implants are frequently produced through additive manufacturing. As all medical devices have to undergo specific washing and sterilization before application, the effects of a predefined cleaning routine that is available to the clinical institutes, washing with chemical agent and formaldehyde fumigation, on the mechanical behavior of printed parts are examined. Mechanical properties of parts manufactured by fused filament fabrication (FFF) and ARBURG plastic freeforming (APF) using two poly(methyl methacrylate) (PMMA)‐based materials, 3Diakon and CYROLITE MD H12, respectively, are analyzed using flexural and impact tests. An influence of cleaning treatments on the mechanical properties of APF samples is not detected. FFF samples, however, show lower impact strength after washing, but not after sterilization. The fracture surfaces, porosity values, or chemical structure assessed by Fourier‐transform infrared (FTIR) spectroscopy could not explain this decrease. Influence of the cleaning treatments on the material itself is assessed using thin compression‐molded specimens. The influence on the stress–strain curves is negligible, apart from a slight but significant reduction in the yield stress. FTIR spectroscopy and scanning electron microscopy analyses of the fracture surfaces do not show detectable differences among differentially treated samples.

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Comparative morphological, thermal, and mechanical characteristics of doped bentonite and dolomite natural clay fillers into high‐density polyethylene

Mahmoud,

Khalifa,

Youssef

et al. 2024

J of Applied Polymer Sci

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Organic–inorganic composites have attracted great interest, due to their remarkable impact, causing improvements in the mechanical properties of polymers when compared with their pure forms. Hence, this study has been attempted to investigate and compare the various properties of high‐density polyethylene (HDPE), separately doped with two different types of clay minerals using melt‐mixing and compression‐molding techniques. The fourier transform infrared spectroscopy (FT‐IR), x‐ray diffraction (XRD), and scanning electron microscope (SEM) were used to characterize the structural and morphological properties of the resulting composites, while, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were employed to characterize their thermal properties. Morphological investigations indicated homogeneous dispersion of both clay materials in the HDPE matrix. Moreover, an investigation was conducted on the mechanical properties of composites, including elastic modulus, yield stress, tensile strain at break, tensile strain at yield, tensile stress at break, and ultimate tensile strength. According to the mechanical data, adding 6.0 wt% of bentonite or dolomite to HDPE led to an increase in the elastic modulus up to 125% and 116% increments, respectively. An increase in the filler content in the composite from 2.0 to 8.0 wt% resulted in a slight decrease in tensile stress at break, yield stress, tensile strain at break, and tensile strain at yield.

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The Effects of Gamma Irradiation on Medical Grade Poly(Methyl Methacrylate)

Cited by 5 publications

References 25 publications

Polymethacrylates

Polymethacrylates

The Effects of Washing and Formaldehyde Sterilization on the Mechanical Performance of Poly(methyl Methacrylate) (PMMA) Parts Produced by Material Extrusion‐Based Additive Manufacturing or Material Jetting

Comparative morphological, thermal, and mechanical characteristics of doped bentonite and dolomite natural clay fillers into high‐density polyethylene

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