Shear Stress and Normal Stress Differences of High-Density Polyethylene Melts
نویسندگان
چکیده
منابع مشابه
Discovered functions for Shear Stress and Pressure Drop of Linear Low Density Polyethylene Using Genetic programming
The esti mati on of the functions that descri be the shear stress and the pressure drop across the short orifice die as a function of shear rate at different mean pressures for linear-low-density polyethylene copolymer (LLDPE) at 190oC is obtained using Genetic Programmi ng (GP) . The GP has been running base d on e xpe rimental data in two cases; shear stress and pressure drop at differe nt me...
متن کاملAnomalous nonlinearities in steady shear of polyethylene melts
High-density polyethylene (HDPE) melts have been previously identified as having an unusually high degree of molecular order, but the rheological implications of this have heretofore not been explored. This has been a serious oversight, inasmuch as HDPE melt processing is one of the major tasks of the world's polymer industry. Here, we investigate several industrial samples of HDPE, covering a ...
متن کاملRheological evidence for high-temperature phase transitions in melts of high-density polyethylene
Melts of commercial high-density polyethylene (M — w = 36–85 6 10) were subjected to the hydrodynamics of a Haake Rheocord blender at temperatures (T) spanning the normal processing range (190–2608C), far beyond the disappearance of solid crystals at about 1408C. Torque measurements revealed a peculiar dependence on T, including transitions at about 2088C and 2278C, and non-Arrhenius behavior a...
متن کاملInstability of elastic filaments in shear flow yields first-normal-stress differences.
Using slender-body hydrodynamics, we study the flow-induced deformation of a high-aspect-ratio elastic filament. For a filament of zero rest curvature rotating in a viscous linear shear flow, our model predicts a bifurcation to shape instabilities due to compression by the flow, in agreement with experimental observations. Further, nonlinear simulations of this shape instability show that in di...
متن کاملStress-structure relation in dense colloidal melts under forward and instantaneous reversal of the shear.
A dense supercooled colloidal melt in forward shear from a quiescent state shows overshoot in the shear stress at 10% strain with an unchanged fluid structure at equal stress before and after overshoot. In addition, we find an overshoot in the normal stress with a monotonic increase in the osmotic pressure at an identical strain. The first and second normal stresses become comparable in magnitu...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Nihon Reoroji Gakkaishi(Journal of the Society of Rheology, Japan)
سال: 1982
ISSN: 0387-1533
DOI: 10.1678/rheology1973.10.3_103