A Positron-Annihilation-Lifetime study of Polymer Blends

1993 ◽  
Vol 321 ◽  
Author(s):  
J. Liu ◽  
Y. C. Jean ◽  
H. Yang
Keyword(s):  
Bisphenol A ◽  
Polymer Blends ◽  
Positron Annihilation ◽  
Free Volume ◽  
Weight Fraction ◽  
Bisphenol A Polycarbonate ◽  
Positron Annihilation Lifetime ◽  
Miscible Blend ◽  
Immiscible Blend ◽  
Free Volume Hole

ABSTRACTPositron-annihilation-lifetime (PAL) spectroscopy has been utilized to investigate the free-volume properties of two types of polymer blends, a miscible blend of bisphenol-A polycarbonate (PC) and tetramethyl bisphenol-A polycarbonate (TMPC), and an immiscible blend of PC and polystyrene (PS). In the miscible blend, the free-volume hole size and its fraction follow a linear relationship with respect to the weight fraction while in the immiscible blend, the relationship is not linearly additive. The free-volume hole distributions in the immiscible blend are found to be significantly broader than those in the pure polymers. The difference is thought to be a result of the free volume formed and associated with the conformation and interchain packing between the dissimilar chains in incompatible polymers.

Studying the Effect of Low α-Radiation Doses on CR-39 Polymers Using Positron Annihilation Lifetime and Mechanical Properties

2012 ◽  
Vol 332 ◽  
pp. 77-83
Author(s):  
M.F. Eissa ◽  
E.M. Hassan ◽  
Emad A. Badawi
Keyword(s):  
Positron Annihilation ◽  
Free Volume ◽  
Alpha Particles ◽  
Polymer Materials ◽  
Fractional Free Volume ◽  
Positron Annihilation Lifetime ◽  
Microhardness Test ◽  
Solid Media ◽  
Free Volume Hole ◽  
Different Doses

Positron annihilation lifetime spectroscopy (PALS) is one of the unique tools for studying free-volume defects in solid media. The microhardness test offers a simple and nondestructive tool for investigating the mechanical behavior of polymer materials. Polyallyl diglycol carbonate (CR-39) track detectors have a variety of applications in science and technology. PALS measurements and microhardness tests were verified for CR-39 irradiated with different doses of alpha particles (0 - 69.20 mGy). The variations in free volume hole size and fractional free volume were obtained by using the PALS method. The small free volume hole sizes were found at doses 27.68 and 44.98 mGy. The microhardness test for the two doses yielded medium values.

scholarly journals Positron Annihilation Lifetime Study on free Volume Changes in TLD by Gamma - irradiation

2004 ◽  
Vol 1 (1) ◽  
pp. 144-148
Author(s):  
Baghdad Science Journal
Keyword(s):  
Gamma Irradiation ◽  
Positron Annihilation ◽  
Free Volume ◽  
Volume Fraction ◽  
Gamma Dose ◽  
Volume Changes ◽  
Positron Annihilation Lifetime ◽  
Free Volume Fraction ◽  
First Time ◽  
Free Volume Hole

Positron annihilation lifetime has been utilized for the first time to investigate the free - volume hole properties in thermolumenscent dosimeter ( TLD ) as a function of gamma-dosc . The hole volume, free volume fraction determined form orthopsitronium lifetime are found to be ?lamatically increase to large values , and then to minimum values as a function ofgamma-dose . The free - volume holes size is found to be 0.163nm’ and to have maximum of 0.166nm^ at the gamma-dose of 0.1 and 0.8 Gy, respectively-

Sign in / Sign up

Export Citation Format

Share Document