Radiation‐induced crystallinity changes in linear polyethylene

Abstract

SynopsisTwo kinds of ultrahigh-molecular-weight linear polyethylene (UHMW PE), together with conventional high-density polyethylene (HDPE), were subjected to 0 irradiation, and changes in their properties were monitored. Elastic modulus increased steadily with dose for all materials, as did the yield stress. A dramatic rise of density with dose was observed in the UHMW P E specimens accompanied by a corresponding increase in heat of fusion, x-ray crystallinity, and peak melting temperature. The magnitude of such changes in HDPE was much smaller. In UHMW P E specimens, the x-ray long period simultaneously decreased but crystal thickness remained constant. No changes in long period occurred in HDPE. The effects are attributed to the scission of tie molecules in UHMW P E followed by a growth in the perfection of the crystal lamellae, and suggest a method for assessing the tie-molecule content of such materials.

Discoloration Effects of High-Dose γ-Irradiation and Long-Term Thermal Aging of (U)HMW-PE

“…As can also be seen in Figure 6, subsequent thermal aging resulted in a decrease of crystallinity back to the initial level, which is most likely due to radical recombination at the higher aging temperature that led again to longer and thus less mobile chains. This observation is in agreement with the results reported so far in literature [25,26].…”

Structural and Physical Properties of Biofield Treated Thymol and Menthol

“…It is postulated that biofield energy may be acted at atomic level in the treated thymol and induced perfect arrangement in the crystals that caused alteration in crystallinity. It was previously reported that high energy radiation treatment appreciably increases the crystallinity in polyethylene and polytetrafluoroethylene [37][38][39]. Similarly, in the present work biofield energy might be acted as a cross linker in thymol and led the formation of crystalline entanglements which enhanced the crystallinity.…”

HIPS/?-irradiated UHMWPE/carbon black blends: Structuring and enhancement of mechanical properties

“…This process is more pronounced in UHMWPE than in HDPE, mainly due to the entanglements effect. 8 Immiscible polymer blends constitute interesting host matrices for the incorporation of conductive fillers, such as carbon black (CB). The multiphase nature of these systems provides an opportunity for the filler to distribute nonuniformly within the phases or at the interface, due to the different properties of the blend components.…”