DYNAMIC MECHANICAL STUDIES OF IRRADIATED POLYPROPYLENE

Journal Article · Sun Apr 01 04:00:00 EST 1962 · J. Polymer Sci.

DOI:https://doi.org/10.1002/pol.1962.1205816602· OSTI ID:4829309

Sauer, J A; Merrill, L J; Woodward, A E

The internal friction and the dynamic modulus of isotactic polypropylene samples subject to varying degrees of pile irradiation were studied at low audio frequencies and over the temperature range from 100 to over 400 deg K. The radiation dosages used varied from 5.4 x lO/sup 17/ to 14 x lO/sup 18/ nvt. For irradiation doses up to about 3 x lO/sup 18/ nvt, one observed change is a decrease in the temperature at which the final upswing in damping and drop in modulus occurs, presumably as a result of defects produced in the crystallites by the irradiation. As the irradiation dose increases above 3 x lO/sup 18/ nvt, all evidence of crystallinity is lost, and the internal friction peak which occurs in the neighborhood of 300 deg K and which is associated with the glass transition of the amorphous regions moves to higher temperatures as a result of the increasing chain-stiffening effect due to crosslinking. The secondary loss peak at 250 deg K attributed to the motion of a small number of segraents in the amorphous regions is found to increase in magnitude with increasing dose. The results of density determinations raade before and after irradiation and also after subsequent exposure of the irradiated samples to melting temperatures and of solvent extraction studies of the irradiated samples confirm the simultaneous occurrence of crosslinking and of crystalline degradation upon pile irradiation of polypropylene samples. (auth)

• Research Organization: Pennsylvania State Univ., University Park
• NSA Number: NSA-16-024253
• OSTI ID: 4829309
• Journal Information: J. Polymer Sci., Journal Name: J. Polymer Sci. Vol. Vol: 58
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

CRYSTALS
DECOMPOSITION
DEFECTS
DENSITY
ELASTICITY
FRICTION
IRRADIATION
LATTICES
MELTING
METALS, CERAMICS, AND OTHER MATERIALS
NEUTRON BEAMS
POLYMERIZATION
POLYMERS
PROPYLENE
RADIATION DOSES
RADIATION EFFECTS
SOLVENT EXTRACTION
TEMPERATURE
TENSILE PROPERTIES