Poly(methyl methacrylate)-block-polysulfide-block-poly(methyl methacrylate) copolymers obtained by free-radical polymerization combined with oxidative coupling

2006 ◽  
Vol 56 (4-5) ◽  
pp. 359-368 ◽  
Author(s):  
Mircea Teodorescu ◽  
Constantin Draghici
Keyword(s):  
Free Radical ◽  
Methyl Methacrylate ◽  
Radical Polymerization ◽  
Oxidative Coupling ◽  
Free Radical Polymerization ◽  
Poly Methyl Methacrylate ◽  
Methacrylate Copolymers

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.

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.

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