Regulator Theory in Emulsion Polymerization. II. Control of Reaction Rate by Diffusion for High Molecular Weight Mercaptans

1946 ◽  
Vol 68 (10) ◽  
pp. 2064-2069 ◽  
Author(s):  
W. V. Smith
Keyword(s):  
Molecular Weight ◽  
Emulsion Polymerization ◽  
High Molecular Weight ◽  
Reaction Rate

THE ROLE OF WATER IN THE FORMATION OF SODIUM TRIPHOSPHATE BY CALCINATION

1954 ◽  
Vol 32 (12) ◽  
pp. 1100-1111 ◽  
Author(s):  
J. D. McGilvery ◽  
A. E. Scott
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Reaction Rate ◽  
Ionic Diffusion ◽  
Fusion Point ◽  
Rapid Formation

The formation of sodium triphosphate by calcination, below the sodium triphosphate fusion point, of various phosphate mixtures of over-all composition 5Na2O.3P2O5.xH2O was investigated. Water plays an important role, decreasing the amounts of pyrophosphate and high molecular weight polyphosphate impurities and increasing the reaction rate under certain conditions. It is suggested that water catalyzes the reactions by: (1) facilitating ionic diffusion, (2) hydrolyzing —P—O—P—linkages, and (3) assisting in the crystallization of sodium triphosphate. With ortho- and pyro-phosphate mixtures temperatures of about 300 °C. and higher are necessary for the rapid formation of sodium triphosphate. With glasses of the composition 5Na2O.3P2O5 good yields may be obtained at temperatures as low as 250 °C. when water is present.

Tailor-made compositional gradient copolymer by a many-shot RAFT emulsion polymerization method

2014 ◽  
Vol 5 (10) ◽  
pp. 3363-3371 ◽  
Author(s):  
Yunlong Guo ◽  
Jianhua Zhang ◽  
Peile Xie ◽  
Xiang Gao ◽  
Yingwu Luo
Keyword(s):  
Molecular Weight ◽  
Emulsion Polymerization ◽  
High Molecular Weight ◽  
Compositional Gradient ◽  
Gradient Copolymers ◽  
Gradient Copolymer ◽  
Polymerization Method

A many-shot RAFT emulsion polymerization method to synthesize gradient copolymers with high molecular weight and a tailor-made compositional gradient.

RAFT-mediated emulsion polymerization of vinyl acetate: a challenge towards producing high molecular weight poly(vinyl acetate)

2012 ◽  
Vol 290 (13) ◽  
pp. 1247-1255 ◽  
Author(s):  
Funian Zhao ◽  
Ali Reza Mahdavian ◽  
Mohammad Bagher Teimouri ◽  
Eric S. Daniels ◽  
Andrew Klein ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Emulsion Polymerization ◽  
High Molecular Weight ◽  
Vinyl Acetate ◽  
High Molecular Weight Poly

scholarly journals Inverse Emulsion Polymerization for the Synthesis of High Molecular Weight Polyacrylamide and Its Application as Sand Stabilizer

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Mahmoud A. Mohsin ◽  
Nuha F. Attia
Keyword(s):  
Molecular Weight ◽  
Emulsion Polymerization ◽  
High Molecular Weight ◽  
Solution Viscosity ◽  
Experimental Conditions ◽  
High Molecular Weight Polymer ◽  
Molecular Weight Polymer ◽  
Inverse Emulsion Polymerization ◽  
Inverse Emulsion ◽  
Molecular Weights

Polyacrylamides constitute a class of polymers that can entirely dissolve or swell in water to form a solution or hydrogel, respectively. Free radical polymerization of acrylamide monomer, using both solution and inverse emulsion polymerization, was applied to produce polyacrylamide with various molecular weights. This investigation was focused on the production of polymers with varying molecular weight, depending on monomer to initiator ratio. Experimental conditions were designed to produce high molecular weight polymers that can be used in stabilization of sand dunes in the arid regions. Synthesized polyacrylamide samples were characterized using Gel Permeation Chromatography and solution viscosity in order to determine the molecular weights and molecular weights distribution. The rheological behavior was also investigated in different polymer concentrations and at various temperatures using Brookfield Rheometer. Lab-scale wind tunnel was used to determine the stability of the sand before and after treatment with the polymer. Compressive stress-strain test was also used to establish the mechanical behavior of the polymer-sand composite under controlled compressive load up to failure. The results showed that the use of high molecular weight polymer gave excellent mechanical and thermal stability.

scholarly journals Preparation of high molecular weight polyvinyl alcohol by emulsifier-free emulsion polymerization

2020 ◽  
Vol 206 ◽  
pp. 02023
Author(s):  
Xinqiu Hong ◽  
Liming Zou ◽  
Jingyang Zhang ◽  
Liujian Wang
Keyword(s):  
Molecular Weight ◽  
Polyvinyl Alcohol ◽  
Emulsion Polymerization ◽  
High Molecular Weight ◽  
Thermo Gravimetric Analysis ◽  
Degree Of Polymerization ◽  
Gravimetric Analysis ◽  
Structure And Property ◽  
H Nmr ◽  
Redox Initiator

In this report, high molecular weight polyvinyl alcohol (PVA) was prepared by emulsifier-free emulsion polymerization, using the redox initiator of potassium persulfate (KPS) / N,N-dimethyl ethanolamine (DMEA). The structure and property of PVA were studied by using ubbelohde viscometer, fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance hydrogen spectroscopy (1H-NMR), X-ray Diffraction (XRD), differential scanning calorimeter (DSC) and thermo gravimetric analysis (TGA). The results showed that the viscosity-average degree of polymerization (DP) of PVA 7506, which was much higher than that of PVA commonly used in industrial production. The syndiotacticity and crystallinity of PVA was 54.2 % and 35.6 %, respectively.

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