Premium
Melt viscosity reduction of polycarbonate with low molar mass liquid crystals
Author(s) -
Motong Noppawan,
Thongyai Supakanok,
Clarke Nigel
Publication year - 2007
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.27193
Subject(s) - polycarbonate , molar mass , materials science , liquid crystal , viscosity , rheology , shear rate , polymer , reduced viscosity , shear (geology) , rheometry , polymer chemistry , composite material , chemical engineering , optoelectronics , engineering
The phase behavior and rheological behavior of low molar mass liquid crystal (LLC) and polycarbonate blends is firstly reported. The results of small angle light scattering (SALS) indicate that the LLC is miscible in the mixture for weight fractions of LLC less than 6%. Mixtures of two different liquid crystals with two different molecular weight of polycarbonate were prepared inside the miscible regime of the blends. Both the complex and steady shear viscosities of the blends were found to be significantly decreased upon addition of small amounts of liquid crystal (1% by weight). At low shear rate, the steady state shear viscosity was similar to the pure polycarbonate, whilst, at higher shear rates, three further regimes of behavior, as has been described for liquid crystals and liquid crystal polymers, were found despite the low concentration of LLC; hence, the rheological properties of the blends can be significantly modified by small concentrations of LLC (as low as 1%). The decrease in melt viscosity of polycarbonate that we observe upon addition of LLC is not due to lubrication effects at the interfaces, as shown by reproducible oscillatory shear flow sweeps. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008