Solution Polymerization Of Methyl Methacrylate Research Articles

Steady-state multiplicity during solution polymerization of methyl methacrylate in a CSTR

This paper examines the steady-state behavior of a CSTR during solution polymerization of methyl methacrylate. Simulation studies reveal the hitherto unreported existence of multiple isolas and unusual multiplicity features, arising from isola evolution for some regions of reactor parameter space. The stability of some of these unusual steady states is analyzed. The influence of the reactor operating conditions on the molecular weight distribution (MWD) is also investigated and the various multiplicity features associated with the MWD are reported. The behavior of the reactor at very high conversion ( > 95%) and the associated MWD profiles are presented. Finally, the practical consequences of these phenomena on reactor control and MWD manipulation are further discussed.

Batch solution polymerization of methyl methacrylate: Parameter estimation

Conversion, number- and weight-average molecular weight data obtained over different operating conditions from a batch solution methyl methacrylate pol

Heterocyclic ylide initiated photopolymerization of methyl methacrylate

Solution polymerization of methyl methacrylate (MMA) was carried out in the presence of visible light (440 nm) using β-picolinium p-chlorophenacylide as a photoinitiator at 30°C. The initiator and monomer exponent values were calculated to be 0·5 and 1·0 ± 0·01, respectively. An average value of k p 2 k t was 4·07 × 10 −2. The polymerization was retarded in the presence of hydroquinone; however, a nonpolar solvent (cyclohexane) enhanced the rate of polymerization. Kinetic data and ESR studies indicate that the overall polymerization takes place by a radical mechanism via triplet carbene formation which acts as a source of free radicals.

Adaptive Pole-Placement Control of a Batch Polymer Reactor

This paper is concerned with the theoretical and practical aspects of adaptive pole-placement controllers. Following a brief review of the theory, the paper outlines an evaluation of an adaptive pole-placement controller. Simulation and experimental results on a batch polymer reactor for the solution polymerization of methylmethacrylate demonstrate the usefulness of this adaptive pole-placement control algorithm.

The kinetics of the polymerization of methyl methacrylate initiated by t-butylmagnesium bromide in THF, toluene or mixed solvent

The kinetics of the solution polymerization of methyl methacrylate in THF, toluene and their mixtures were studied between 200 and 300 K using dilatometry (in the systems where it was valid), gravimetric determination and monitoring monomer and polymer concentrations by NMR spectrometry. The reaction followed zero order kinetics at 200 K, first order kinetics at 275 K and mixed order in between. At both the limits and intermediate range, the reaction followed an integrated rate equation consistent with terminationless propagation proceeding through a complex between monomer and the propagating species. Above 275 K, termination and side reactions were evident and the yields of high mol. wt polymer were small. Density-temperature calibrations for monomer in THF, toluene and mixtures were constructed for the range 190–283 K. However for polymerizations in toluene-rich mixtures, where very high mol. wt polymer forms, the contraction did not correlate linearly with conversion.

Effects of Benzenethiol on the Continuous Solution Polymerization of Methyl Methacrylate

In order to obtain the relationships between the conversion and the number average degree of polymerization and those between the conversion and theresidence time, the solution polymerization of methyl methacrylate (MMA) by azobisisobtyronitrile (AIBN) in benzene was carried out in a continuously stirred tank reactor (CSTR), using benzenethiol as the chain transfer agent.It was found that the conversion increased as the benzenethiol concentration was increasedin the range of 8x10-4 to 3.2x10-8 (mol/l) and that the index of molecular weight distribution (Q=Pw/Pn) decreased as the benzenethiol concentration was increased.

The ferric hydroxide/hydrazine system as an initiator of vinyl polymerization

AbstractThe reaction between ferric hydroxide and hydrazine was used to initiate the solution polymerization of methyl methacrylate. Polymerization occurs readily at pH > 6, over a wide range of iron concentration and of temperature. The initiation reaction appears to be of heterogeneous nature, like those in similar metal hydroxide/hydrazine systems.

Branching of anionic poly(methyl methacrylate)

AbstractA viscometric determination of the degree of branching γ, of poly(methyl methacrylate) obtained by anionic polymerization proved the reaction of the growing center of poly(methyl methacrylate) with the ester group of another polymer molecule, accompanied by the formation of a trifunctional branch point. This reaction occurs if the solution polymerization of methyl methacrylate is initiated: (1) with butyllithium at −78°C only on attaining 100% conversion and after a long time or at +20°C immediately after the polymerization has set in; (2) with lithium tert‐butoxide at +20°C after a long time. The degree of branching of poly(methyl methacrylates) obtained under similar conditions in the presence of tetrahydrofuran reaches higher values than for polymers prepared in toluene. The tacticity of polymers does not affect the experimentally determined γ values.

The Precipitated Polymerization of Methyl Methacrylate in Cyclohexane

The solution polymerization of methyl-methacrylate (MMA) in cyclohexane was carried out to study the mechanism of the precipitated polymerization. The autoacceleration effect appeared from the initial stage of the polymerization and the smaller the concentration of monomer the more remarkable was its effect. As to the distribution of the chain length, there were two clear peaks and as polymerization proceeded, the peak of the low degree of polymerization was disappeared. These experimental results suggest that to make clear the mechanism of the precipitated polymerization analyticaly, it is effective to divide the reaction into two parts and to treat separately, namely the reaction in liquid phase and in solid phase.

The manganic hydroxide–hydrazine hydrate system as an initiator of vinyl polymerization

AbstractThe reaction of hydrazine hydrate with manganic hydroxide and its application to the solution polymerization of methyl methacrylate has been studied. The kinetic evidence suggests that the hydrazine and the monomer are both adsorbed on the surface of the manganic hydroxide sol and that the decomposition of the hydrazine and the polymerization of the methyl methacrylate follow zero‐order kinetics. The rate of polymerization increases slowly with increasing temperature, the activation energy for the polymerization being 4.9 ± 0.2 kcal/mole.

The cupric sulfate–hydrazine system as an initiator of vinyl polymerization. I. The polymerization of methyl methacrylate in aqueous solution in the presence of oxygen

AbstractThe cupric sulfate–hydrazine system has been used to initiate the aqueous solution polymerization of methyl methacrylate at pH 9.25 in the presence of oxygen. At cupric sulfate concentrations greater than the saturation solubility of cupric hydroxide, hydrazine is adsorbed on, and decomposes on, the surface of the hydroxide. The kinetics of the decomposition are zero‐order both in the absence and the presence of monomer. The initiation of the polymerization occurs both at the surface of the cupric hydroxide on to which some monomer is adsorbed and also in solution. Below the saturation solubility of cupric hydroxide, the initiation reaction between cupric ions and hydrazine occurs in solution.

Cupric sulfate–hydrazine system as an initiator of vinyl polymerization. II. Polymerization of methyl methacrylate in aqueous solution in the absence of oxygen

AbstractThe cupric sulfate–hydrazine system has been used to initiate the aqueous solution polymerization of methyl methacrylate at pH 9.25 in the absence of oxygen. There is no decomposition of hydrazine on the surface of the reduced cupric hydroxide until a flocculant precipitate is formed (cupric sulfate concentration of about 10−3 mole/1). Below this concentration, the initiating reaction occurs solely in solution, the rate of polymerization decreasing when the reaction mixture becomes depleted in cupric ions. When a suitable surface area of the precipitated polymer is attained, adsorption and decomposition of hydrazine occurs on its surface, causing further initiation of polymerization.

(74)メチルメタクリレートのベンゼン溶液重合において,触媒としての過酸化ベンゾイルとジメチルアニリンの使用比が重合初速度に及ぼす影響について(補遺)

(74)メチルメタクリレートのベンゼン溶液重合において,触媒としての過酸化ベンゾイルとジメチルアニリンの使用比が重合初速度に及ぼす影響について(補遺)