scholarly journals Different Dependence of Tear Strength on Film Orientation of LLDPE Made with Different Co-Monomer

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 434 ◽  
Author(s):  
Yi Ren ◽  
Ying Shi ◽  
Xuerong Yao ◽  
Yujing Tang ◽  
Li-Zhi Liu
Keyword(s):  
Molecular Weight ◽  
Crystal Orientation ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Machine Direction ◽  
Tear Strength ◽  
Similar Dependence ◽  
Similar Density ◽  
Shrinkage Property

Crystal orientations, tear strength and shrinkage of Linear Low-Density PolyEthylene (LLDPE) films made with different processes (compressed, cast and blown) were investigated. The films were made with three different LLDPE resins, respectively, which have similar density and molecular weight but are made with different comonomers (1-butene, 1-hexene and 1-octene), in order to investigate if tear strength in Machine Direction (MD) of the LLDPE films made with different comonomer has similar dependence on crystal orientation. Our study indicates that the films made of 1-hexene and 1-octene based LLDPE resins have significantly higher intrinsic tear strength and less decrease in MD tear strength for a given film orientation. That is, for a given orientation in MD, the MD tear drops dramatically for films made with butene-based resin but much less decrease for the films made with hexene and octene-based resins. The shrinkage property at high temperature shows a good correlation with crystal orientation and the fraction of the crystals melted at this temperature.

Effect of the blow-up ratio on morphology and engineering properties of three-layered linear low-density polyethylene blown films

2017 ◽  
Vol 34 (1) ◽  
pp. 27-42 ◽  
Author(s):  
Suthakarn Auksornkul ◽  
Siriwat Soontaranon ◽  
Chonthicha Kaewhan ◽  
Pattarapan Prasassarakich
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
Transverse Direction ◽  
Blow Up ◽  
Engineering Properties ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Film Morphology ◽  
Linear Low Density Polyethylene ◽  
Machine Direction

A series of linear low-density polyethylene films were produced using a three-layer co-extrusion machine. How the blow-up ratio and resin characteristics affected the final film morphology and engineering properties were studied. The crystalline morphology and orientation during the blown film process of the low-density polyethylene film were investigated using small-angle X-ray scattering, transmission electron microscopy and scanning electron microscopy. Increasing the blow-up ratio increased the transverse direction molecular orientation and decreased the machine direction orientation. The resulting low-density polyethylene morphology was a regular lamellar stacking parallel to the machine direction. The film morphology strongly influenced the mechanical properties. Increasing the blow-up ratio from 1.7 to 2.8 decreased the machine direction tensile strength by 14% and increased the transverse direction tensile strength up to 27% for both the low-density polyethylene/1-butene and low-density polyethylene/1-octene co-monomers, while the machine direction tear strength increased up to 36% and the transverse direction decreased by 16%. Moreover, the first and second heating characteristics from differential scanning calorimeter showed the inherent crystallinity change with increasing blow-up ratio for both the low-density polyethylene/1-octene and the low-density polyethylene/1-butene copolymer. The crystalline orientation changes induced with increasing blow-up ratio affected the film water vapor and oxygen permeability.

Molecular Weight Dependency of Rheological Characteristics of Linear Low Density Polyethylene

1985 ◽  
Vol 29 (3) ◽  
pp. 323-334 ◽  
Author(s):  
D. Acierno ◽  
A. Brancaccio ◽  
D. Curto ◽  
F. P. La Mantia ◽  
A. Valenza
Keyword(s):  
Molecular Weight ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Rheological Characteristics ◽  
Linear Low Density Polyethylene
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