Tensile creep and deformation mechanisms in oriented low-density polyethylene

1975 ◽  
Vol 10 (10) ◽  
pp. 1751-1762 ◽  
Author(s):  
A. Cowking
Keyword(s):  
Deformation Mechanisms ◽  
Tensile Creep ◽  
Low Density Polyethylene ◽  
Low Density

scholarly journals Microstructural Contributions of Different Polyolefins to the Deformation Mechanisms of Their Binary Blends

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1171 ◽  
Author(s):  
Astrid Van Belle ◽  
Ruben Demets ◽  
Nicolas Mys ◽  
Karen Van Kets ◽  
Jo Dewulf ◽  
...  
Keyword(s):  
Polymer Blends ◽  
Tensile Deformation ◽  
Deformation Mechanisms ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Mechanical Recycling ◽  
Immiscible Polymer Blends ◽  
Binary Blends ◽  
Brittle Behavior ◽  
Clear Cut

The mixing of polymers, even structurally similar polyolefins, inevitably leads to blend systems with a phase-separated morphology. Fundamentally understanding the changes in mechanical properties and occurring deformation mechanisms of these immiscible polymer blends, is important with respect to potential mechanical recycling. This work focuses on the behavior of binary blends of linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP) under tensile deformation and their related changes in crystallinity and morphology. All of these polymers plastically deform by shear yielding. When unmixed, the high crystalline polyolefins HDPE and PP both exhibit a progressive necking phenomenon. LDPE initiates a local neck before material failure, while LLDPE is characterized by a uniform deformation as well as clear strain hardening. LLDPE/LDPE and LLDPE/PP combinations both exhibit a clear-cut matrix switchover. Polymer blends LLDPE/LDPE, LDPE/HDPE, and LDPE/PP show transition forms with features of composing materials. Combining PP in an HDPE matrix causes a radical switch to brittle behavior.

Long-Term Strength of Polymer Blends from Recycled Materials

2013 ◽  
Vol 43 (3) ◽  
pp. 59-66
Author(s):  
R. K. Krastev ◽  
S. Djoumaliisky ◽  
I. Borovanska
Keyword(s):  
Brittle Fracture ◽  
Polymer Blends ◽  
Calculation Method ◽  
High Density Polyethylene ◽  
Tensile Creep ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Term Strength ◽  
Short Term

Abstract This report presents data on the long-term strength of five composites made of plastic waste. They contain low density polyethylene, high density polyethylene, polypropylene and polystyrene (LDPE, HDPE, PP and PS). Long-term strength is determined experimentally by tensile creep to fracture. The experimentally determined long-term strength is compared to predictions for its probabilistic boundaries. The calculation method of these predictions uses data from short-term experiments. The calculated predictions are true for four compositions which exhibit ductile fracture. The composite containing 50 wt.% PS has the greatest strength (of the tested specimens) and has brittle fracture. Its calculated estimate of long-term strength is not consistent with the experimental one.

scholarly journals Macromolecular Insights into the Altered Mechanical Deformation Mechanisms of Non-Polyolefin Contaminated Polyolefins

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 239
Author(s):  
Ruben Demets ◽  
Marie Grodent ◽  
Karen Van Van Kets ◽  
Steven De De Meester ◽  
Kim Ragaert
Keyword(s):  
Interfacial Adhesion ◽  
Tensile Deformation ◽  
Linear Structure ◽  
Polyamide 6 ◽  
Deformation Mechanisms ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Pure Material ◽  
Polymer Type

Current recycling technologies rarely achieve 100% pure plastic fractions from a single polymer type. Often, sorted bales marked as containing a single polymer type in fact contain small amounts of other polymers as contaminants. Inevitably, this will affect the properties of the recycled plastic. This work focuses on understanding the changes in tensile deformation mechanism and the related mechanical properties of the four dominant types of polyolefin (PO) (linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP)), contaminated with three different non-polyolefin (NPO) polymers (polyamide-6 (PA-6), polyethylene terephthalate (PET), and polystyrene (PS)). Under the locally elevated stress state induced by the NPO phase, the weak interfacial adhesion typically provokes decohesion. The resulting microvoids, in turn, initiate shear yielding of the PO matrix. LLDPE, due to the linear structure and intercrystalline links, is well able to maintain high ductility when contaminated. LDPE shows deformation similar to the pure material, but with decreasing ductility as the amount of NPO increases. Addition of 20 wt% PA-6, PET, and PS causes a drop in strain at break of 79%, 63%, and 84%, respectively. The typical ductile necking of the high-crystalline HDPE and PP is strongly disturbed by the NPO phase, with a transition even to full brittle failure at high NPO concentration.

Effect of 110 keV electrons on the deformation mechanisms of low density polyethylene

2014 ◽  
Vol 109 ◽  
pp. 59-70 ◽  
Author(s):  
Erming Rui ◽  
Jianqun Yang ◽  
Xingji Li ◽  
Chaoming Liu ◽  
Feng Tian
Keyword(s):  
Deformation Mechanisms ◽  
Low Density Polyethylene ◽  
Low Density
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