Entry rate coefficients in emulsion polymerization systems

1986 ◽  
Vol 82 (7) ◽  
pp. 2247 ◽  
Author(s):  
Ian A. Penboss ◽  
Robert G. Gilbert ◽  
Donald H. Napper
Keyword(s):  
Emulsion Polymerization ◽  
Rate Coefficients ◽  
Entry Rate

Polymer-Fraction Dependence of Entry Rate Coefficients in Emulsion Polymerization

1992 ◽  
Vol 45 (12) ◽  
pp. 2057 ◽  
Author(s):  
GL Leslie ◽  
DH Napper ◽  
RG Gilbert
Keyword(s):  
Emulsion Polymerization ◽  
Aqueous Phase ◽  
Rate Coefficient ◽  
Monomer Concentration ◽  
Weight Fraction ◽  
Rate Coefficients ◽  
Seeded Emulsion Polymerization ◽  
Entry Rate ◽  
Initiator Efficiency ◽  
Approach To Steady State

Data on the rate of approach to steady state in a series of studies of the seeded emulsion polymerization of styrene yield the dependence of the rate coefficient for entry of free radicals into latex particles as a function of the weight-fraction polymer and hence of monomer concentration in the aqueous phase. The results are in accord with a model for the entry process (i.e., for the initiator efficiency) based on aqueous-phase propagation and termination being the rate-controlling events.

Propagation rate coefficients from electron spin resonance studies of the emulsion polymerization of methyl methacrylate

1986 ◽  
Vol 19 (5) ◽  
pp. 1303-1308 ◽  
Author(s):  
Mathew J. Ballard ◽  
Robert G. Gilbert ◽  
Donald H. Napper ◽  
Peter J. Pomery ◽  
Paul W. O'Sullivan ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Methyl Methacrylate ◽  
Emulsion Polymerization ◽  
Electron Spin ◽  
Propagation Rate ◽  
Rate Coefficients ◽  
Spin Resonance

An approach to predicting indoor radon concentration based on depressurisation measurements

2020 ◽  
pp. 1420326X2092474
Author(s):  
James A McGrath ◽  
Miriam A Byrne
Keyword(s):  
Radon Concentration ◽  
Indoor Radon ◽  
Power Laws ◽  
Rate Coefficients ◽  
Indoor Radon Concentration ◽  
Entry Rate ◽  
Energy Retrofit ◽  
Building Characteristics ◽  
Passive Measurements ◽  
Radon Concentrations

Exposure to radon is recognised as the second-leading cause of lung cancer after tobacco smoke. The passive measurements typically take up to three months to be representative of the annual radon concentration. A recently developed approach depressurises a dwelling to heighten the convective radon flux determining radon entry rate coefficients. The current study characterises the ventilation status, air tightness and eight selected hourly air change rates measurements, of a sample of naturally ventilated dwellings in Ireland. The household averaged air change rate ranged from 0.28 to 1.87 h−1 and airtightness measurements ranged from 4.830 to 9.423 m3 h−1 m−2 @ 50 Pa, depending on the building characteristics. The experimentally obtained values were used to parameterise a computational model for these selected dwellings and to predict radon concentrations. The radon entry rate power laws ranged from 0.18ΔP0.97 to 1.28ΔP1.18 Bq s−1. Probabilistic functions were generated based on the experimental data and predicted radon concentrations were within one standard deviation of the experimentally measured values in three out of four cases. The data generated can be used in modelling simulations to predict indoor radon concentrations based on local meteorological conditions, building characteristics, ventilation guidelines and energy-retrofit measurements.

Exit process and re-entry rate in emulsion polymerization

Polymer ◽  
1996 ◽  
Vol 37 (10) ◽  
pp. 1941-1947 ◽  
Author(s):  
J.U. Kim ◽  
Hong H. Lee
Keyword(s):  
Emulsion Polymerization ◽  
Entry Rate

scholarly journals Mathematical Modeling of the Production of Elastomers by Emulsion Polymerization in Trains of Continuous Reactors

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1508
Author(s):  
Enrique Saldívar-Guerra ◽  
Ramiro Infante-Martínez ◽  
José María Islas-Manzur
Keyword(s):  
Emulsion Polymerization ◽  
Rate Coefficient ◽  
Mechanistic Model ◽  
A Priori ◽  
Particle Diameter ◽  
Styrene Butadiene Rubber ◽  
Copolymer Composition ◽  
Butadiene Rubber ◽  
Entry Rate ◽  
Monomer Composition

A mechanistic model is proposed to describe the emulsion polymerization processes for the production of styrene–butadiene rubber (SBR) and acrylonitrile–butadiene rubber (NBR) elastomers in trains of continuous stirred tank reactors (CSTRs). A single model was used to describe both processes by choosing the proper physicochemical parameters of each system. Most of these parameters were taken from literature sources or estimated a priori; only one parameter (the entry rate coefficient) was used as an adjustable value to reproduce the kinetics (mainly conversion), and another parameter (the transfer to polymer rate coefficient) was used to fit the molecular weight distribution (MWD) experimental values from plant data. A 0-1-2 model for the number of particles and for the moments of the MWD was used to represent with more fidelity the compartmentalization effects. The model was based on approaches used in previous emulsion polymerization models published in the literature, with the premise of reaching a compromise between the level of detail, complexity, and practical value. The model outputs along the reactor train included conversion, remaining monomer composition, instantaneous and accumulated copolymer composition, the number of latex particles and particle diameter, polymerization rate, the average number of radicals per particle, average molecular weights, and the number of branches per chain.

Direct Measurement of Oligomers Entry Rate onto Latex Particles in an Emulsion Polymerization

1998 ◽  
Vol 31 (5) ◽  
pp. 1686-1689 ◽  
Author(s):  
Catherine Marestin ◽  
Alain Guyot ◽  
Jérôme Claverie
Keyword(s):  
Emulsion Polymerization ◽  
Direct Measurement ◽  
Entry Rate ◽  
Latex Particles
Sign in / Sign up

Export Citation Format

Share Document