Role of anionic and nonionic surfactants on the control of particle size and latex colloidal stability in the seeded emulsion polymerization of butyl methacrylate

2006 ◽  
Vol 102 (4) ◽  
pp. 3083-3094 ◽  
Author(s):  
Valter Castelvetro ◽  
Cinzia De Vita ◽  
Giacomo Giannini ◽  
Simone Giaiacopi
Keyword(s):  
Particle Size ◽  
Emulsion Polymerization ◽  
Nonionic Surfactants ◽  
Colloidal Stability ◽  
Butyl Methacrylate ◽  
Seeded Emulsion Polymerization

Semibatch Seeded Emulsion Polymerization of Acrylic Monomers: Bimodal Particle Size Distribution

1997 ◽  
Vol 34 (7) ◽  
pp. 1221-1236 ◽  
Author(s):  
Chorng-Shyan Chern ◽  
Tseng-Jung Chen ◽  
Shinn-Yih Wu ◽  
Horng-Bin Chu ◽  
Chun-Fu Huang
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Emulsion Polymerization ◽  
Seeded Emulsion Polymerization ◽  
Acrylic Monomers

scholarly journals Colloidal Stability of Apolar Nanoparticles: The Role of Particle Size and Ligand Shell Structure

ACS Nano ◽  
2018 ◽  
Vol 12 (6) ◽  
pp. 5969-5977 ◽  
Author(s):  
Thomas Kister ◽  
Debora Monego ◽  
Paul Mulvaney ◽  
Asaph Widmer-Cooper ◽  
Tobias Kraus
Keyword(s):  
Particle Size ◽  
Shell Structure ◽  
Colloidal Stability ◽  
Ligand Shell

scholarly journals Crosslinking in Semi-Batch Seeded Emulsion Polymerization: Effect of Linear and Non-Linear Monomer Feeding Rate Profiles on Gel Formation

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 596
Author(s):  
Chang Liu ◽  
Amit K. Tripathi ◽  
Wei Gao ◽  
John G. Tsavalas
Keyword(s):  
Emulsion Polymerization ◽  
Feed Rate ◽  
Monomer Concentration ◽  
Butyl Methacrylate ◽  
Gel Formation ◽  
Seeded Emulsion Polymerization ◽  
Linear Profile ◽  
Gel Fraction ◽  
Non Linear ◽  
Monomer Feed

Waterborne latex is often called a product-of-process. Here, the effect of semi-batch monomer feed rate on the kinetics and gel formation in seeded emulsion polymerization was investigated for the copolymerization of n-butyl methacrylate (n-BMA) and ethylene glycol dimethacrylate (EGDMA). Strikingly, the gel fraction was observed to be significantly influenced by monomer feed rate, even while most of the experiments were performed under so-called starve-fed conditions. More flooded conditions from faster monomer feed rates, including seeded batch reactions, counterintuitively resulted in significantly higher gel fraction. Chain transfer to polymer was intentionally suppressed here via monomer selection so as to focus mechanistic insights to relate only to the influence of a divinyl monomer, as opposed to being clouded by contributions to topology from long chain branching. Simulations revealed that the dominant influence on this phenomenon was the sensitivity of primary intramolecular cyclization to the instantaneous unreacted monomer concentration, which is directly impacted by monomer feed rate. The rate constant for cyclization for these conditions was determined to be first order and 4000 s−1, approximately 4 times that typically observed for backbiting in acrylates. This concept has been explored previously for bulk and solution polymerizations, but not for emulsified reaction environments and especially for the very low mole fraction divinyl monomer. In addition, while gel fraction could be dramatically manipulated by variations in linear monomer feed rates, it could be markedly enhanced by leveraging non-linear feed profiles built from combination sequences of flooded and starved conditions. For a 2 h total feed time, a fully linear profile resulted in 30% gel while a corresponding non-linear profile with an early fast-feed segment resulted in 80% gel.

Fibrin Formation: The Role of the Fibrinogen-Fibrin Monomer Complex

1976 ◽  
Vol 36 (01) ◽  
pp. 037-048 ◽  
Author(s):  
Eric P. Brass ◽  
Walter B. Forman ◽  
Robert V. Edwards ◽  
Olgierd Lindan
Keyword(s):  
Particle Size ◽  
Induction Period ◽  
Fibrin Clot ◽  
Clot Formation ◽  
Appreciable Amount ◽  
Buffer System ◽  
Homeostatic Mechanism ◽  
Fibrin Formation ◽  
Fibrin Monomer

SummaryThe process of fibrin formation using highly purified fibrinogen and thrombin was studied using laser fluctuation spectroscopy, a method that rapidly determines particle size in a solution. Two periods in fibrin clot formation were noted: an induction period during which no fibrin polymerization occurred and a period of rapid increase in particle size. Direct measurement of fibrin monomer polymerization and fibrinopeptide release showed no evidence of an induction period. These observations were best explained by a kinetic model for fibrin clot formation incorporating a reversible fibrinogen-fibrin monomer complex. In this model, the complex serves as a buffer system during the earliest phase of fibrin formation. This prevents the accumulation of free polymerizable fibrin monomer until an appreciable amount of fibrinogen has reacted with thrombin, at which point the fibrin monomer level rises rapidly and polymerization proceeds. Clinically, the complex may be a homeostatic mechanism preventing pathological clotting during periods of elevated fibrinogen.

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