Surface embrittlement of polyethylene pipe grade resin. Final report, 1 Sep 1979 - 31 Oct 1980

Technical Report · Sun Nov 01 04:00:00 EST 1981

OSTI ID:6207716

Broutman, L J

Techniques were developed to simulate the effect of a brittle surface on the mechanical behavior of polyethylene. Polyethylene films were exposed to ultraviolet radiation so as to degrade them. These films were than heat fused to polyethylene substrates. It was demonstrated that specimens having bonded films on their surface were embrittled. In addition to attempting to simulate naturally embrittled surfaces by bonding of brittle films to the polyethylene substrate, specimens of polyethylene were subjected to U.V. radiation to determine the effect of surface embrittlement. Severe embrittlement was demonstrated by measuring tensile ultimate strain to failure which was much more sensitive to embrittlement than conventional impact strength. Additional experiments were conducted utilizing sharp razor notches of various depths in surface of polyethylene to evaluate their effect on tensile strain to failure. Experiments were conducted as a function of strain rate which has been demonstrated to have a strong influence on thenotch length required to cause embrittlement. It is shown that the notch length required to cause embrittlement is greater than the film thickness required to cause embrittlement. It has also been shown that U.V. exposure of the polyethylene surface increases the degree of crystallinity and hence establishes a residual stress state in the exposed polymer which has been measured by curvature techniques.

• Research Organization: Illinois Inst. of Tech., Chicago (USA)
• OSTI ID: 6207716
• Report Number(s): N-8310204; PB-82-214370; GRI-81/0030
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360403* -- Materials-- Polymers & Plastics-- Mechanical Properties-- (-1987)
BONDING
CRYSTALLIZATION
ELECTROMAGNETIC RADIATION
EMBRITTLEMENT
FABRICATION
JOINING
MATERIALS
MECHANICAL PROPERTIES
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
PHASE TRANSFORMATIONS
PLASTICS
POLYETHYLENES
POLYMERS
POLYOLEFINS
RADIATIONS
RESINS
SIMULATION
STRAIN RATE
SYNTHETIC MATERIALS
ULTRAVIOLET RADIATION