scholarly journals Effects of Molecular Weight and Polymer Composition on Coupling Reactions of Lipase and Polyacrylic Acid or Acrylic Acid/Acrylamide Copolymers.

1996 ◽  
Vol 52 (4) ◽  
pp. 206-212
Author(s):  
Machiko Shimada Takigami ◽  
Osamu Tamura ◽  
Shoji Takigami ◽  
Yoshio Nakamura
Keyword(s):  
Molecular Weight ◽  
Acrylic Acid ◽  
Polyacrylic Acid ◽  
Polymer Composition ◽  
Coupling Reactions ◽  
Acrylamide Copolymers

Kinetics of crystal growth of calcium sulfate dihydrate. The influence of polymer composition, molecular weight, and solution pH

1988 ◽  
Vol 66 (6) ◽  
pp. 1529-1536 ◽  
Author(s):  
Zahid Amjad
Keyword(s):  
Molecular Weight ◽  
Crystal Growth ◽  
Induction Period ◽  
Functional Groups ◽  
Polyacrylic Acid ◽  
Calcium Sulfate ◽  
Polymer Composition ◽  
Supersaturated Solution ◽  
Solution Ph ◽  
Calcium Sulfate Dihydrate

A seeded crystal growth technique has been used to study the influence of solution pH and temperature ranging from 25 to 50 °C on the performance of polymers of varying functional groups as calcium sulfate dihydrate (CaSO4•2H2O, gypsum) crystal growth inhibitors. Results indicate that at constant temperature and at a constant solution pH, crystallization in the presence of polyacrylic acids is preceded by an initial slow growth reaction, hereafter called induction period, following which crystal growth of gypsum proceeds with a rate close to that in pure supersaturated solution. Results suggest that at a constant pH, polyacrylic acid concentration, molecular weight, and temperature greatly affect the duration of induction period. Kinetic data collected as a function of solution pH in the range 2.5 to 9.0 suggest that solution pH has a marked effect on the induction period. The observed dependence of induction period on solution pH may be explained in terms of the degree of ionization of polyacrylic acid. Among the polymers of varying functional groups studied, i.e. carboxyl, sulfonate, acrylamide, dimethyldiallylammonium, etc., only those polymers having carboxyl group showed marked inhibitory activity for the growth of gypsum crystals.

scholarly journals Effect of precipitation inhibitors on calcium phosphate scale formation

1989 ◽  
Vol 67 (5) ◽  
pp. 850-856 ◽  
Author(s):  
Zahid Amjad
Keyword(s):  
Molecular Weight ◽  
Calcium Phosphate ◽  
Acrylic Acid ◽  
Polyacrylic Acid ◽  
Scale Formation ◽  
Comparative Data ◽  
Polycarboxylic Acids ◽  
Precipitation Inhibitors ◽  
Ph Stat

The highly reproducible pH-stat technique was used to study the influence of various types of inhibitors on the precipitation of calcium phosphate from solution. Three types of inhibitors were evaluated: (1) homo- and copolymers of acrylic acid, (2) polyphosphate and phosphonates, and (3) polycarboxylic acids. Experimental variables studied included pH, temperature, and inhibitor dosage all of which were found to greatly affect the precipitation of calcium phosphate. The role of polyacrylic acid molecular weight is addressed. Comparative data for the various types of inhibitors is discussed. Keywords: precipitation inhibitors, calcium phosphate scale formation.

Synthesis of poly(methyl methacrylate)-b-poly(acrylic acid) by DPE method

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Dong Chen ◽  
Ruixue Liu ◽  
Zhifeng Fu ◽  
Yan Shi
Keyword(s):  
Molecular Weight ◽  
Acrylic Acid ◽  
Methyl Methacrylate ◽  
Diblock Copolymer ◽  
Self Assembly ◽  
Gel Permeation Chromatography ◽  
Amphiphilic Diblock Copolymer ◽  
Poly Methyl Methacrylate ◽  
Copolymer Poly ◽  
Poly Acrylic Acid

AbstractAmphiphilic diblock copolymer poly(methyl methacrylate)-b-poly(acrylic acid) (PMMA-b-PAA) was prepared by 1,1-diphenylethene (DPE) method. Firstly, free radical polymerization of methyl methacrylate was carried out with AIBN as initiator in the presence of DPE, giving a DPE-containing PMMA precursor with controlled molecular weight. tert-Butyl acrylate (tBA) was then polymerized in the presence of the PMMA precursor, and PMMA-b-PtBA diblock copolymer with controlled molecular weight was prepared. Finally, amphiphilic diblock copolymer PMMA-b-PAA was obtained by hydrolysis of PMMA-b-PtBA. The formation of PMMA-b-PAA was confirmed by 1H NMR spectrum and gel permeation chromatography. Transmission electron microscopy and dynamic light scattering were used to detect the self-assembly behavior of the amphiphilic diblock polymers in methanol.

Low molecular weight poly(acrylic acid) as a salt scaling inhibitor in oilfield operations

2005 ◽  
Vol 2 (3) ◽  
pp. 212-219 ◽  
Author(s):  
S. Moulay ◽  
M. Boukherissa ◽  
F. Abdoune ◽  
F. Z. Benabdelmoumene
Keyword(s):  
Molecular Weight ◽  
Acrylic Acid ◽  
Low Molecular Weight ◽  
Salt Scaling ◽  
Oilfield Operations ◽  
Poly Acrylic Acid
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