scispace - formally typeset
Journal ArticleDOI

Polymerization of methyl methacrylate with the use of cetyl trimethyl ammonium bromide-benzoyl peroxide combination as the initiating system

01 Jan 1978-European Polymer Journal (Pergamon)-Vol. 14, Iss: 10, pp 855-859
Abstract: Methyl methacrylate (MMA) was polymerized at 40 in the presence of dimethyl formamide (DMF), using cetyl trimethyl ammonium bromide with benzoyl peroxide (CTABBZ 2 O 2 ) as the initiating system. At high dilutions the rate of polymerization was proportional to (initiator) 1–2 . In near-bulk conditions using low [DMF], the rate was practically independent of [BZ 2 O 2 ], while the kinetic order with respect to CTAB was about 0.16. The polymerization was inhibited by hydroquinone. A radical mechanism is suggested for the polymerization with primary radical termination significant in near-bulk systems and bimolecular termination significant for high dilution with DMF. Effects of various other solvents or additives on the polymerization were examined. DMF, acetonitrile and pyridine act as rate accelerating diluents; benzene, methanol, chloroform and acetone as inert diluents; formamide and acetamide cause pronounced retardation.
Topics: Polymerization (59%), Benzoyl peroxide (57%), Ammonium bromide (56%), Methyl methacrylate (54%), Acetamide (53%)
Citations
More filters

Journal ArticleDOI
Abstract: Photopolymerization of MMA at 35° was studied using benzophenone (BP)-dimethylaniline (DMA) combination as photo-redox initiator. Initiator exponent was 0.13; monomer exponent was 1.0 in other solvents. Photoreduction of BP by DMA is considered to produce chain-initiating radicals and analysis of kinetic data indicates this process to be solvent and monomer dependent. Chlorinated solvents are indicated to be much more reactive than other solvents. The photopolymerization is also characterized by significant primary radical termination.

23 citations


Journal ArticleDOI
Abstract: Styrene was polymerized with azobiscyanovaleric acid (ACVA) to obtain carboxy-telechelic polystyrene. Our aim was to synthesize an oligostyrene with a molecular weight of about 2000 g/mol. Thus, styrene was polymerized at 90 °C, where t 1/2ACVA is very short, and at very high initiator concentrations. In these conditions a new termination reaction appeared, known as the primary radical termination (PRT). At first, PRT was observed by a deviation from the simple kinetic law. Then, the constant of PRT was determined by several kinetic models to be more important than the constant of bimolecular termination. Finally, the PREDICI simulation program was used to confirm the predominance of PRT. This simulation program allowed the determination of the constant of primary radical deactivation k rr and the influence of this reaction on the conversion rate.

18 citations


Journal ArticleDOI
N.N. Dass1
Abstract: Systeme donneur d'electrons-tetrachlorure de carbone; systeme donneur d'electrons-dioxyde de soufre et halogenure organique; systeme carbonyle et CCl 4 ; systeme induit photochimiquement; systemes divers

15 citations


Journal ArticleDOI
Abstract: Polymerization of MMA was carried out in near-bulk and in fairly dilute solutions in DMF at 40° with (1) CPB-BZ2O2 combination as the redox initiator in the dark and (2) CPB as the sole photoinitiator in visible light. Rp was proportional to ([CPB] [BZ2O2])0.18 for the redox polymerization and to [CPB]0.35 for the photopolymerization both in near-bulk (10% DMF, v/v) and in high dilution (50% DMF, v/v). Polymerization was inhibited by hydroquinone in each case indicating a radical mechanism. Effect of several solvents/additives on the polymerization revealed that dimethyl formamide, acetonitrile and pyridine acted as rate enhancing solvents in the redox polymerization while in the photopolymerization they acted as normal diluents; benzene, methanol, acetone and chloroform exhibited inert nature while formamide and acetamide behaved as retarding additives in both types of polymerization. Initiator transfer of the degradative type reasonably explains kinetic nonidealities.

11 citations


Journal ArticleDOI
Abstract: Photopolymerization of methyl methacrylate (MMA) was kinetically studied using near UV/visible light at 40°C and by employing the morpholine (MOR)–bromine (Br 2 ) charge transfer (CT) complex as the photoinitiator. The rate of polymerization ( R p ) was dependent on the morpholine:bromine mole ratio; the 1:2 (MOR–Br 2 ) CT complex acted as the latent initiator complex C which underwent further complexation with monomer molecules to give the actual initiator complex, I. Using a 1:2 (MOR–Br 2 ) CT complex as the latent initiator, the initiator exponent for bulk photopolymerization of MMA was 0.08 and the monomer exponent determined from studies of photopolymerization in a carbon tetrachloride diluted system was 1.20. Benzoquinone behaved as a strong inhibitor and the polymers tested positive for the incorporation of bromine atoms as end groups. Polymerization followed a radical mechanism. Kinetic non-ideality was revealed by low (≪0.5) initiator exponent and a monomer exponent of greater than unity; it was explained in terms of primary radical termination.

11 citations


References
More filters

Book
01 Jan 1953-

16,813 citations


Book
01 Jan 1957-

710 citations


Journal ArticleDOI
01 Jan 1962-Polymer
Abstract: This is the first report of a series on the properties of dilute solutions of conventional polymethyl methacrylate designed to characterize the chain length and its distribution, the intramolecular chain interactions and the thermodynamic interactions with solvent and their effects on the chain dimensions, and to establish the accuracy and reproducibility of such data Herein [η] M n relations in benzene at 30° are established for both fractionated and unfractionated polymers from ebulliometric determinations in benzene for Mn from 200 to 6 × 103 and from osmotic pressure measurements in two or more solvents for Mn from 104 to 7 × 105 Evidence is presented that the values of Mn so obtained are generally accurate and reproducible within an uncertainty of three per cent The observed curvature and its molecular weight dependence in osmotic pressure/concentration relations is in general accord with theoretical expectation The identity of [η] M n relationships found for unfractionated polymers prepared both with and without added chain transfer agent indicates that both have the same molecular weight distribution and that disproportionation is the predominant mode of termination of methyl methacrylate radicals at 60°

154 citations


Journal ArticleDOI
Abstract: Styrene has been polymerized at 60° and methyl methacrylate at 0 and 60° using 2,2′-azo-bis-isobutyronitrile labeled with C14 as initiator. The average number of labeled end groups per molecule has been determined for the various polymers and so the relative importances of combination and disproportionation have been assessed. It has been found that polystyrene radicals undergo combination at 60°. In the case of methyl methacrylate, disproportionation occurs about 6 times as frequently as combination at 60° and about 1.5 times as frequently at 0° the activation energy for disproportionation is about 4 kcal. per mole greater than that for combination. The copolymerization of styrene and methyl methacrylate at 60° has been studied by this technique. It is found that when polystyrene radicals interact with polymethyl methacrylate radicals at this temperature combination occurs. The rates of initiation in the copolymerizations have been determined by a new method; the rate of this step is found to be virtually independent of the composition of the monomer mixture.

130 citations