Tribological and mechanical characterization of PMMA/HAp nanocomposites obtained by free- radical polymerization

MRS Advances ◽  
2018 ◽  
Vol 3 (63) ◽  
pp. 3763-3768
Author(s):  
Virginia Campos-Sanabria ◽  
María T. Hernández-Sierra ◽  
Micael G. Bravo-Sánchez ◽  
Luis D. Aguilera-Camacho ◽  
J. S. García-Miranda ◽  
...  
Keyword(s):  
Free Radical ◽  
Methyl Methacrylate ◽  
Water Absorption ◽  
Benzoyl Peroxide ◽  
Radical Polymerization ◽  
Mechanical Characterization ◽  
Tribological Behavior ◽  
Free Radical Polymerization ◽  
Poly Methyl Methacrylate

ABSTRACTPoly (methyl methacrylate)/hydroxyapatite (PMMA/HAp) nanocomposites with HAp nanoparticles content of 12 wt.% were obtained by free-radical polymerization synthesis. Three different concentrations of benzoyl peroxide (PBO) of 3, 6, and 12 wt.% were studied. The results showed that the concentration of PBO has an effect on the performance of composites. In particular, the nanocomposite with the highest concentration of PBO presented the best mechanical and tribological behavior, as well as the lowest values of water absorption and porosity percent.

scholarly journals Effect of Ferocene Concentration on the Percent Conversion and Molecular Weight of Poly(Methyl Methacrylate) Homopolymers

2017 ◽  
Vol 14 (2) ◽  
pp. 311-319
Author(s):  
Baghdad Science Journal
Keyword(s):  
Molecular Weight ◽  
Free Radical ◽  
Methyl Methacrylate ◽  
Benzoyl Peroxide ◽  
Radical Polymerization ◽  
Free Oxygen ◽  
Poly Methyl Methacrylate ◽  
Methacrylate Monomer ◽  
Percent Conversion ◽  
Methyl Methacrylate Monomer

This research is addressing the effect of different ferrocene concentration (0.00, 2.15x10-3, 4.30x10-3, 8.60x10-3, and 12.9x10-3) on the bulk free radical polymerization of methyl methacrylate monomer in benzene using benzoyl peroxide as initiator. The polymerization was conducted at 60º C under free oxygen atmosphere. The resulting polymers were characterized by FTIR. The results were compared with the presence and absence of ferrocene at 10% conversion. The %conversion was 3.04% with no ferrocene present in the polymerization medium and its increase to 9.06 with a first lowest ferrocene concentration added, i.e. 2.15 x10-3mol/l. This was positively reflected on the poly(methyl methacrylate) molecular weight measured by viscosity technique, especially in the presence of ferrocene.

Tacticity of Poly(Methyl Methacrylate). Evidence for a Penpenultimate Group Effect in Free-Radical Polymerization

1986 ◽  
Vol 39 (1) ◽  
pp. 43 ◽  
Author(s):  
G Moad ◽  
DH Solomon ◽  
TH Spurling ◽  
SR Johns ◽  
RI Willing
Keyword(s):  
Free Radical ◽  
Methyl Methacrylate ◽  
Radical Polymerization ◽  
Free Radical Polymerization ◽  
Group Effect ◽  
Poly Methyl Methacrylate

The tacticity of poly(methyl methacrylate ) prepared by free-radical polymerization has been determined by analysing the carbonyl region of the 13C n.m.r . spectrum. This analysis demonstrates that the addition of poly(methyl methacrylyl ) radical to methyl methacrylate in benzene at 60°C is subject to a significant penpenultimate unit effect. The probability of forming a meso dyad is some 20% less if the preceding dyad in the chain is also meso . The polymerization (60°C, benzene) is described by the following parameters P(m) = 0.202, P(m|m) = 0.159, P(r | m) = 0.212.

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