The spontaneous polymerization of methyl methacrylate: 6. Polymerization in solution: participation of transfer agents in the initiation reaction

Lingnau, J.; Meyerhoff, G.

doi:10.1016/0032-3861(83)90233-1

Cited by 28 publications

(15 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Low rates of polymerization of MMA were found in nonpolar solvents,23 and high rates of polymerization were found in halogenated solvents and polar, protic solvents, such as thiophenol. Halogenated solvents and thiophenol were reported to increase the rate of polymerization because of the rapid chain transfer and crossing of diradical species from an unstable singlet to a stable triplet state via collisions with the heavy halogen or sulfur atom 23–25. However, the heavy atom effect in thiophenol was found to be less evident in comparison to halogenated solvents.…”

Section: Introductionmentioning

confidence: 99%

“…In nonstyrenic monomers, such as methyl methacrylate (MMA), Diels–Alder adducts lack the tendency to undergo hydrogen abstraction to generate monoradicals. Stickler, Meyerhoff, and coworkers18–25 studied the spontaneous thermal polymerization of MMA at high temperatures (100–130°C) and reported low‐conversion (≤ ∼ 5%), high‐average‐molecular‐weight polymers and the formation of a significant amount of dimers, trimers, and oligomers after 75 h of batch operation. The presence of diradical species and the initiation mechanism were identified from the predominant formation of a linear unsaturated dimer, dimethyl 1‐hexene 2,5 carboxylate 19–21…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Theoretical considerations lead to the conclusion that sustained polymer chain growth is not possible from diradical species 23. The role of the solvent as a chain‐transfer species was studied in the spontaneous thermal polymerization of MMA23–25 and pentafluorostyrene 26. Low rates of polymerization of MMA were found in nonpolar solvents,23 and high rates of polymerization were found in halogenated solvents and polar, protic solvents, such as thiophenol.…”

Section: Introductionmentioning

confidence: 99%

“…The role of the solvent as a chain‐transfer species was studied in the spontaneous thermal polymerization of MMA23–25 and pentafluorostyrene 26. Low rates of polymerization of MMA were found in nonpolar solvents,23 and high rates of polymerization were found in halogenated solvents and polar, protic solvents, such as thiophenol. Halogenated solvents and thiophenol were reported to increase the rate of polymerization because of the rapid chain transfer and crossing of diradical species from an unstable singlet to a stable triplet state via collisions with the heavy halogen or sulfur atom 23–25.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Experimental study of the spontaneous thermal homopolymerization of methyl andn‐butyl acrylate

Srinivasan

Kalfas

Petkovska

et al. 2010

J of Applied Polymer Sci

View full text Add to dashboard Cite

This article presents an experimental study of the spontaneous thermal homopolymerization of methyl acrylate (MA) and n-butyl acrylate (nBA) in the absence of any known added initiators at 120 and 140 C in a batch reactor. The effects of the solvent type, oxygen level, and reaction temperature on the monomer conversion and polymer average molecular weights were investigated. Three solvents, dimethyl sulfoxide (DMSO; polar, aprotic), cyclohexanone (polar, aprotic), and xylene (nonpolar) were used. The spontaneous thermal polymerization of MA and nBA in DMSO resulted in a lower conversion and higher average molecular weights in comparison to polymerization in cyclohexanone and xylene under the same conditions. The highest final conversion of both monomers was obtained in cyclohexanone. The high polymerization rate in cyclohexanone was most likely due to an additional initiation mechanism where cyclohexanone complexed with the monomer to generate free radicals. Bubbling air through the mixture led to a higher monomer conversion during the early stage of the polymerization and a lower polymer average molecular weight in xylene and cyclohexanone; this indicated the existence of a distinct behavior between the air-and nitrogen-purged systems. Matrixassisted laser desorption/ionization time-of-flight analysis of the polymer samples taken from nitrogen-bubbled batches did not reveal fragments from initiating impurities. On the basis of the identified families of peaks, monomer self-initiation is suggested as the principal mode of initiation in the spontaneous thermal polymerization of MA and nBA at temperatures above 100 C.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Experimental study of the spontaneous thermal homopolymerization of methyl andn‐butyl acrylate

Srinivasan

Kalfas

Petkovska

et al. 2010

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

Development of a poly(methyl methacrylate‐co‐n‐butyl methacrylate) copolymer binder system

Vail

Barlow

Beaman

et al. 1994

J of Applied Polymer Sci

View full text Add to dashboard Cite

SYNOPSISLow molecular weight poly (methylmethacrylate) and poly (methylmethacrylate-co-n-butylmethacrylate) emulsion-based polymers are developed for use as fugitive binders of high temperature powders to be used with the rapid prototyping method known as selective laser sintering. Kinetics of the homopolymerization of methylmethacrylate and n-butylmethacrylate are found to deviate from Smith-Ewart Type I1 predictions. Reactivity ratios for the monomer pair are determined and indicate the pair to yield random copolymers. Molecular weight was controlled by the addition of chain transfer agents. Several transfer agents were studied and one, Iso-octyl-3-mercaptopropionate, was selected for use with emulsion polymerizations. Glass transition temperatures of the homopolymers and copolymers were studied.

show abstract

Free‐Radical Acrylic Polymerization Kinetics at Elevated Temperatures

Wang

Hutchinson

2010

Chem Eng & Technol

View full text Add to dashboard Cite

Free-radical acrylic homo-and copolymerization kinetics are reviewed, focusing on secondary reactions that impact the polymerization rate and polymer molecular weight (MW) under industrially-relevant synthesis conditions. Dependent on the monomer type (acrylate, methacrylate, styrene), mechanisms that must be considered include chain-end depropagation, monomer self-initiation, formation and reaction of midchain radicals, and incorporation of macromonomers formed by b-scission of midchain radicals. The relative importance of these reactions varies with temperature and, for copolymerization, monomer composition. A comprehensive treatment of these complexities has been completed for polymerizations conducted up to 180°C, but further work is required to extend the applicability of the model to even higher temperatures. IntroductionThe production of low-density polyethylene and associated copolymers at 200-300°C and high pressure is perhaps the bestknown example of high-temperature free-radical polymerization (FRP). However, an increasing number of acrylic resins, produced from a mixture of monomers selected from the methacrylate, acrylate, and styrene families, are also manufactured under higher temperature conditions (>120°C) in homogeneous solution. Low-molecular-weight acrylic resins are the base polymer components for many automotive coatings due to their excellent resistance to chemicals, solvents, ultraviolet light, and abrasion, as well as their exterior durability after crosslinking on the surface of the vehicle [1]. High-temperature conditions are used to produce a variety of other materials for coatings, adhesives, and paints [2]. These conditions are chosen to increase production rates and to decrease (or eliminate) the solvent employed in the formulation while maintaining reasonable solution viscosity [2][3][4].While commercially advantageous, the high polymerization temperatures greatly promote the occurrence of secondary reactions that have a strong impact on polymerization rate and polymer MW, such as monomer self-initiation, chain depropagation, and the formation and subsequent reaction of midchain radicals and unsaturated polymer chains (macromonomers). These reactions occur in addition to the well-known and well-understood set of basic FRP mechanisms consisting of initiation, propagation, termination, and chain transfer [5,6]. This article provides an overview and summarizes recent experimental and modeling efforts by our group and other researchers to improve the understanding of these mechanisms. As most high-temperature acrylic polymerization processes involve multiple monomers, the complexities of including these reactions in copolymerization will also be addressed. An accurate treatment of high-temperature FRP kinetics is a critical component of larger-scale process models used to predict the influence of the operating conditions on reaction rate and polymer properties, guide the selection and optimization of standard operating conditions for existing and new polymer grades, and guide process ...

show abstract

The spontaneous polymerization of methyl methacrylate: 6. Polymerization in solution: participation of transfer agents in the initiation reaction

Cited by 28 publications

References 20 publications

Experimental study of the spontaneous thermal homopolymerization of methyl andn‐butyl acrylate

Experimental study of the spontaneous thermal homopolymerization of methyl andn‐butyl acrylate

Development of a poly(methyl methacrylate‐co‐n‐butyl methacrylate) copolymer binder system

Free‐Radical Acrylic Polymerization Kinetics at Elevated Temperatures

Contact Info

Product

Resources

About