transient elongational viscosity (Pa s) [omega] angular frequency (rad/s) [lambda] characteristic elastic time Abbreviations CG constrained geometry DMTA dynamic mechanical thermal analyzer DR draw ratio FLH frost line height HDPE high-density polyethylene LCB long chain branches LDPE low density polyethylene LLDPE linear low density polyethylene MD machine direction MFI melt flow index ULDPE
Ultra low density polyethylene Z-N Ziegler-Natta
The Characterization of the functionalized polymers allowed observing that both ULDPE and SEBS were slightly degraded during the functionalization and that the functionalization degree of ULDPE-g-DEM, expressed as percentage by weight of grafted diethyl maleate, was higher than the SEBS-g-DEM on (Table 1).
Anyway, the functionalization with DEM of ULDPE modified more the interfacial tension values between it and LDPE than the modification of SEBS.
At the desired 80/20 SIS/ULDPE
blend, the ULDPE
particles were small and well dispersed.
In polyethylenes, particularly ULDPE, crystallizability is dependent on short chain branching distribution and/or copolymer composition.
ULDPE whole polymer was run "as received," while fractions were filtered from solution and vacuum dried at room temperature for three days then run "as prepared.
Figure I is a qualitative illustration of the comonomer distribution in ULDPE and is basically the weight fraction of eluting polymer as a function of temperature.
Like the effect of velocity on the coefficient, the ULDPE, LLDPE, and LDPE resins showed stronger dependencies with pressure as compared with the HDPE resins.
The coefficient for the ULDPE did, however, increase slightly with increasing temperature at temperatures above about 115 [degrees] C, and the coefficient for the HDPE resin with a density of 0.
The ULDPE, LLDPE, and LDPE resins under most situations forward well during extrusion, and thus there is no loss of feeding and there are no wide variations in the first extruder zone pressures.
A comparison of Exceed 1012CA and Attane 4201 showed that though the ULDPE by itself has lower haze and higher gloss, adding 10% of either of two ExxonMobil LDPEs (7.
Houston, reportedly offers the excellent toughness associated with mLLDPE plus lower heat-seal temperatures and other advantages over conventional Ziegler-Natta VLDPEs or ULDPEs for flexible packaging.