Physical properties of epoxy and free volume evaluated by positron annihilation spectroscopy

Abstract

Abstract;The macroscopic physical properties of commercially available bisphenol -A epoxy resins cured by acid anhydride4n which amount of the plasticizer, polypropyleneglycol was changed systematically have been measured and were compared with the amount of free volume evaluated by the positron annihilation technique. The lifetime and the intensity of orthopositronium were used to evaluate the amount of the free volume in the epoxy resins. It was found that up to the certain amount of plasticizer, the amount of the free volume did not increase so much and then showed the marked increase. The close correlations were found between the amount of the free volume and the macroscopic physical properties such as hardness and specific volume.

The Impact of Plasticizer and Degree of Hydrolysis on Free Volume of Poly(vinyl alcohol) Films

“…There is a very modest decrease in the I 3 parameter with propylene glycol concentration. This effect has been previously observed in plasticized films [13,33], and although in some cases has been attributed to a hole-filling mechanism [10], the increase in cavity radius with plasticizer concentration suggests that a likely reason for the decrease in I 3 could be the result of quenching of o -Ps by the plasticizer or an increased number of sites where the positronium precursors can be trapped, rather than a decrease in void concentration. Although Equation (3) could be used to calculate the fractional free volume, the use of the determined positron parameters (τ 3 , I ) to calculate free volume can only be justified when void concentration is the sole factor governing o -Ps intensity [32].…”

Influence of the plasticization on free volume in polyvinyl chloride

“…The increase of the t 3 value with the the free volume holes because it gaves the inforincreasing amount of the plasticizer was observed mation on the o-Ps formation probability. Wang by Okada et al 20 and Nishijima et al 28 They used et al 11 and Kobayashi et al 30 proposed a semepoxy resin bisphenol A and polypropyleneglycol iempirical equation that may be used to evaluate as a plasticizer. Wang et al 29 carefully measured the fractional free volume f : the lifetimes of positrons in PVC.…”

“…18 Plasticization of polymers have also been investigated. [19][20][21] In our previous article, 22 we presented results of positron lifetime Positron annihilation spectroscopy is widely used measurements in polyvinyl chloride (PVC) plastifor investigations of different aspects of polymer cized with the aid of dioctyl phthalate. properties [1][2][3][4][5][6] and positron behavior in polymers.…”

Free Volume in Plastified Poly(Vinyl Chlorate)

“…The influence of plasticizers on positron annihilation in polymers is presented in Ref. [14]. In this paper we present some preliminary results of positron lifetime measurements in polyvinyl chlorate) with two different (20% and 30%) concentration of three plasticizers.…”