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.

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.

Synthesis and thermal properties of triblock copolymers of methyl methacrylate using combination of anionic and controlled radical polymerization: Poly(methyl methacrylate) center block bearing different microstructures

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhengji Song ◽  
Carole Pelletier ◽  
Yinghua Qi ◽  
Jasim Ahmed ◽  
Sunil K. Varshney ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Block Copolymers ◽  
Methyl Methacrylate ◽  
Radical Polymerization ◽  
Triblock Copolymers ◽  
Controlled Radical Polymerization ◽  
Alkyl Methacrylate ◽  
Poly Methyl Methacrylate ◽  
H Nmr

AbstractABA and/or ABC type triblock copolymers were synthesized by living anionic and controlled radical polymerization in which poly(methyl methacrylate) was used as central block. The structural composition of these block copolymers were determined by 1H NMR. The block length/molecular weight and microstructure of these polymers were measured by SEC. The microstructure of resultant central alkyl methacrylate block can be tailored from highly syndiotactic to highly isotactic structure by varying the solvent and/or initiator. The thermal and rheological properties of center poly(methyl methacrylate) block and poly(styreneb- methyl methacrylate-b- styrene) tri block copolymers were studied in detail.

scholarly journals Initiator Feeding Policies in Semi-Batch Free Radical Polymerization: A Monte Carlo Study

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1291 ◽  
Author(s):  
Ali Seyedi ◽  
Mohammad Najafi ◽  
Gregory T. Russell ◽  
Yousef Mohammadi ◽  
Eduardo Vivaldo-Lima ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Monte Carlo ◽  
Free Radical ◽  
Methyl Methacrylate ◽  
Radical Polymerization ◽  
Average Molecular Weight ◽  
Free Radical Polymerization ◽  
Monte Carlo Algorithm ◽  
Single Shot ◽  
The Impact

A Monte Carlo simulation algorithm is developed to visualize the impact of various initiator feeding policies on the kinetics of free radical polymerization. Three cases are studied: (1) general free radical polymerization using typical rate constants; (2) diffusion-controlled styrene free radical polymerization in a relatively small amount of solvent; and (3) methyl methacrylate free radical polymerization in solution. The number- and weight-average chain lengths, molecular weight distribution (MWD), and polymerization time were computed for each initiator feeding policy. The results show that a higher number of initiator shots throughout polymerization at a fixed amount of initiator significantly increases average molecular weight and broadens MWD. Similar results are also observed when most of the initiator is added at higher conversions. It is demonstrated that one can double the molecular weight of polystyrene and increase its dispersity by 50% through a four-shot instead of a single shot feeding policy. Similar behavior occurs in the case of methyl methacrylate, while the total time drops by about 5%. In addition, policies injecting initiator at high monomer conversions result in a higher unreacted initiator content in the final product. Lastly, simulation conversion-time profiles are in agreement with benchmark literature information for methyl methacrylate, which essentially validates the highly effective and flexible Monte Carlo algorithm developed in this work.

Synthesis of acrylic hot-melt adhesive based on poly(methyl methacrylate)-b-poly(2-ethylhexyl acrylate) copolymer using atom transfer radical polymerization for a nylon fabric bonding system

2019 ◽  
Vol 89 (23-24) ◽  
pp. 5177-5186
Author(s):  
Chung-Feng Jeffrey Kuo ◽  
Jiong-Bo Chen ◽  
Po-Yen Chen ◽  
Garuda Raka Satria Dewangga
Keyword(s):  
Molecular Weight ◽  
Block Copolymer ◽  
Methyl Methacrylate ◽  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Atom Transfer ◽  
Poly Methyl Methacrylate ◽  
Bonding System ◽  
Nylon Fabric ◽  
Hot Melt

Adhesives, such as hot-melt adhesives (HMAs), are widely used in the textile industry for bonding layers of materials and have replaced traditional sewing methods. The block copolymer is a common type of HMA that provides excellent physical features and mechanical properties compared with others. Acrylate-based monomers, methyl methacrylate (MMA), and 2-ethylhexyl acrylate (2-EHA) were used as ingredients to form a linear block copolymer using atom transfer radical polymerization. MMA provides excellent cohesive strength, while 2-EHA provides good adhesion properties. An end-brominated poly(methyl methacrylate) (PMMA-Br) macroinitiator was synthesized from a MMA monomer and initiator, with the best composition obtained by the addition of a 0.6 mol initiator. The macroinitiator had the lowest molecular weight with highest conversion (97%). The addition of a 0.3 mol macroinitiator showed the lowest molecular weight with the highest conversion of acrylic copolymer PMMA- b-poly(2-ethylhexyl acrylate) (PEHA). The glass transition temperature increased with the addition of the macroinitiator concentration, from −43.7℃ to −37.6℃. The thermal stability was reduced with the addition of macroinitiator content, from 332.37℃ to 286.81℃. The shear strength and peel strength of the PMMA- b-PEHA HMAs on nylon fabrics were enhanced from 11.24 to 16.92 kg cm−2 and from 0.29 to 0.61 kg cm−1, respectively, and did not change significantly after being washed 50 times and then kept in low-temperature storage, with the addition of the macroinitiator concentration. The block copolymer PMMA- b-PEHA prepared in this study could be used as a HMA for nylon fabric bonding systems.

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