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Dependence of intrinsic viscosity and molecular size on molecular weight of partially hydrolyzed polyacrylamide
Author(s) -
Zhang Hao,
Feng Yujun
Publication year - 2021
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.50850
Subject(s) - intrinsic viscosity , polyacrylamide , radius of gyration , polymer , virial coefficient , hydrodynamic radius , aqueous solution , viscosity , rheology , polymer chemistry , chemistry , random coil , hydrolysis , molar mass distribution , static light scattering , dynamic light scattering , analytical chemistry (journal) , chemical engineering , materials science , thermodynamics , chromatography , organic chemistry , copolymer , crystallography , nanotechnology , composite material , circular dichroism , physics , nanoparticle , engineering
As a typical water‐soluble polymer, ultra‐high molecular weight (UHMW) partially hydrolyzed polyacrylamide (HPAM) has been widely used in various industries as thickeners or rheology modifiers. However, precise determination of its critical physical parameters such as molecular weight, radius of gyration ( R g ) and hydrodynamic radius ( R h ) were less documented due to their high viscosity in aqueous solution. In this work, the molecular structure of five UHMW‐HPAM samples with different MW was elucidated by 1 H and 13 C NMR spectroscopy, and their solution properties were characterized by both static and dynamic light scattering. It is found that all the second virial coefficient ( A 2 ) values are positive and approaching zero, indicating of a good solvent of 0.5 M NaCl for UHMW‐HPAM. The weight‐average molecular weight ( M w ) dependence of molecular size and intrinsic viscosity [ η ] for these series of HPAM polymers with MW ranging from 4.81 to 15.4 × 10 6 g·mol −1 can be correlated as R g = 3.52 × 10 −2 M w 0.51 , R h = 1.97 × 10 −2 M w 0.51 , and [ η ] = 6.98 × 10 −4 M w 0.91 , respectively. These results are helpful in understanding the relationship between molecular weight and coil size of HPAM polymers in solution, and offer references for quick estimation of molecular weight and screening of commercial UHMW‐HPAM polymers for specific end‐users.