Accession Number:

AD1167351

Title:

Processing-Structure-Function Relationships in the Production of High-Performance Oriented Polyethylene

Descriptive Note:

[Technical Report, Technical Report]

Corporate Author:

ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD

Personal Author(s):

• Plemmons, Dayne A.

Report Date:

2022-04-01

Pagination or Media Count:

60

Abstract:

The ultra-high strength and modulus observed in oriented polymeric systems are the result of the high degree of molecular alignment of covalently bound repeating units. Orientation takes place under intense flow conditions when chains align with the direction of force. For flexible molecules such as polyethylene PE, conditions for orientation are slightly more complicated given the chain-folded nature of the polymer crystals and the ability for chains to relax from a taut state. Nonetheless, under the appropriate processing conditions, highly oriented PE fibers exhibit among the highest specific tensile strength and modulus of any industrially relevant material. Structural factors dictating both the ability of the polymer chains to orient and the observed mechanical properties are numerous and multiscale. The molecular architecture of the chains, the morphology of the semi-crystalline lamellar clusters, and the fibrillar structure formed during solid-state deformation all play a significant role during processing and end-use. Here, processing-structure-property relationships across multiple stages of oriented PE production are reviewed and discussed. The production is divided into three distinct phases polymer synthesis, consolidation, and orientation each of which introduces new levels of structural hierarchy. At each level, structural features dictating functional behavior relevant to subsequent stages and end-use i.e., rheology, solid-state deformation, and mechanical properties are outlined and examined in relation to process parameters. As an illustrative processing relationship, resin characteristics and deformation behavior of a candidate HDPE resin are included and contextualized. It is expected that optimization of process conditions towards end-use properties will aid in development of novel structural and ballistic composites.

Descriptors:

• fiber spinning
• materials science
• materials testing
• materials processing
• mechanics
• material degradation processes
• materials
• polyethylenes
• materials laboratories
• manufacturing
• tensile strength
• composite materials
• mechanical properties
• mechanical working
• tensile properties
• failure mode and effect analysis
• biomedical and dental materials

Subject Categories:

• Plastics
• Armor
• Manufacturing and Industrial Engineering and Control of Production Systems

Distribution Statement:

[A, Approved For Public Release]