Free‐radical grafting of monomers to polydienes. II. Kinetics and mechanism of styrene grafting to polybutadiene

Brydon, A.; Burnett, G. M.; Cameron, G. Gordon

doi:10.1002/pol.1974.170120509

Cited by 80 publications

(28 citation statements)

References 4 publications

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“…28 for a solution polymerization of St in the presence of PB at 60°C, was developed. The model distinguished between each of the consumed and produced polymer species, with the aim of calculating the detailed molecular macrostructure of the reaction mixture.…”

Section: Introductionmentioning

confidence: 99%

Bulk polymerization of styrene in presence of polybutadiene: Calculation of molecular macrostructure

Estenoz

Valdez

Oliva

et al. 1996

J. Appl. Polym. Sci.

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SYNOPSISIn our previous publication the detailed molecular macrostructure generated in a solution polymerization of styrene (St) in the presence of polybutadiene (PB) at 6OoC, was theoretically calculated. In this work, an extended kinetic mechanism that incorporates monomer thermal initiation, chain transfer to the rubber, chain transfer to the monomer, and the gel effect is proposed, with the aim of simulating a bulk high-impact polystyrene (HIPS) process. The mathematical model enables the calculation of the bivariate weight chainlength distributions (WCLDs) for the total copolymer and for each of the generated copolymer topologies and the univariate WCLDs for the free polystyrene (PS), the residual PB, and the crosslinked PB topologies. These last topologies are characterized by the number of initial PB chains per molecule; copolymer topologies are characterized by the number of PS and PB chains per molecule. The model was validated with published literature data and with new pilot plant experiments that emulate an industrial HIPS process. The literature data correspond to a dilute solution polymerization at a constant low temperature with chemical initiation and a bulk polymerization at a constant high temperature with thermal initiation. The new experiments consider different combinations of prepolymerization temperature, initiator concentration, and solvent concentration. One of the main conclusions is that most of the initial PB is transformed into copolymer. For example, for a prepolymerization temperature of 12OOC with addition of initiator, the experimental measurements indicate that the final total rubber mass is approximately three times higher than the initial PB. Also, according to the model predictions, the final weight fractions are: free PS, 0.778; graft copolymer, 0.220; initial PB, 0.0015; and purely crosslinked PB, 0.0005. The final graft copolymer exhibits the following characteristics: average molecular weights, Mn,c = 492,000 and Mw,c = 976,000; average weight fraction of St, 0.722; and average number of PS and PB branches per molecule, 5.19 and 1.13, respectively. 0 1996JohnWiley & Sons, Inc.

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Section: Introductionmentioning

confidence: 99%

Bulk polymerization of styrene in presence of polybutadiene: Calculation of molecular macrostructure

Estenoz

Valdez

Oliva

et al. 1996

J. Appl. Polym. Sci.

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“…At the final time, topology P(,,z, is more abundant than is the primary ( "H-shaped" ) topology P(l,z). Clearly, the "primary" (1,1) and (1,2 ) topologies are the first in their series to be consumed.…”

Section: Simulation Examplementioning

confidence: 99%

“…Copolymer-forming termination 1 (by combination ) : ( 8 ) kt P',+S',-,P n , m = l , 2 , ... 2 (by combination): (9) kt P',+P',-+P n , m = l , 2 , . .…”

Section: Ntrodu Ctlo Nmentioning

confidence: 99%

Grafting of styrene onto polybutadiene: Calculation of the molecular macrostructure

Estenoz

Meira

1993

J of Applied Polymer Sci

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SYNOPSISThe radical-induced grafting of styrene onto polybutadiene a t 60°C and in dilute solution is theoretically investigated, with the aim of estimating the detailed molecular macrostructure of the evolving polymer mixture. T o this effect, the kinetic mechanism proposed by Brydon et al. [J. Polym. Sci. Polym. Chem. Ed., 11, 3255 (1973) and 12, 1011 (1974)l was extended to evaluate the bivariate weight chain-length distribution (WCLD) for each of different copolymer topologies generated along the polymerization. Each molecular topology is characterized by two integers: the number of grafted styrene chains and the number of incorporated butadiene chains. Apart from the bivariate WCLDs for every topology and for the total copolymer, the molecular weight distributions of the accumulated polystyrene and of the unreacted polybutadiene are calculated. The model predictions of global variables (monomer conversion, polymer production, average molecular weights, grafting efficiencies, and average number of graft sites per reacted polybutadiene molecule) closely match the experimental measurements in the cited publications. 0 1993

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“…This requires the rubber carrying reactive groups for the forming polymer or reactive sites formation in the rubber chains during polymerization. [29][30][31] A typical situation is the interaction between the polymerizing monomer and rubber unsaturation. Moreover, radical formation onto the rubber backbone can also induce rubber grafting and crosslinking, thus influencing the final properties of the blend.…”

mentioning

confidence: 99%

Submicron structured polymethyl methacrylate/acrylonitrile–butadiene rubber blends obtained via gamma radiation induced “in situ” polymerization

et al. 2004

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ABSTRACT:The morphology and properties of PMMA/rubber blends, obtained through gamma radiation induced "in situ" polymerization of methyl methacrylate (MMA) in the presence of small quantities of an acrylonitrile-butadiene based rubber (ABN), are presented. Different systems have been obtained by irradiating at a fixed irradiation dose rate and temperature, varying the integrated dose. All the blends obtained were characterized with respect to their melt state and solid state dynamic-mechanical response and mechanical tensile properties. In particular, the effect on the blend properties of prolonging the irradiation time was investigated. Furthermore, a morphological characterization through atomic force microscopy (AFM) was performed in order to determine how the irradiation conditions affect the ABN rubber particle size and distribution. Finally, the stability of the obtained morphologies was investigated by performing post-irradiation thermal treatments at a temperature close to the glass transition of pure PMMA.

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Free‐radical grafting of monomers to polydienes. II. Kinetics and mechanism of styrene grafting to polybutadiene

Cited by 80 publications

References 4 publications

Bulk polymerization of styrene in presence of polybutadiene: Calculation of molecular macrostructure

Bulk polymerization of styrene in presence of polybutadiene: Calculation of molecular macrostructure

Grafting of styrene onto polybutadiene: Calculation of the molecular macrostructure

Submicron structured polymethyl methacrylate/acrylonitrile–butadiene rubber blends obtained via gamma radiation induced “in situ” polymerization

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