Study of structural characteristics of HDPE/CaCO3 nanocomposites by positrons

Effect of TiO2 nano‐filler on the electrical conductivity and free volume parameters of PSAN/TiO2 nanocomposites

“…However, in semi crystalline polymers, o-Ps may be formed within the interstitial free volumes and at the crystalline amorphous interface region [17][18][19][20][21][22][23]. In polymer nanocomposites, the free volume properties are strongly affected by the amount and type of filler used and the formation of o-Ps occurs at the polymer-inorganic particles interface region [5,24]. The addition of nanoparticle results the interfacial interactions between the surface of nanoparticles and the polymer matrix [25].…”

Potassium layered polytitanates influence on low-pressure polyethylene properties in wide concentrations range

“…However at introduction of 1% of PPT its increase is observed in comparison with the original polymer. Comparing the obtained data with the results of polyethylene filling with nanodispersed calcium carbonate with an average particle diameter of 20 nm and the degree of filling of 5-30 % [18] it could be noted that polytitanates even at high degrees of filling provide better properties of the composite. Despite the fact that the original polyethylene chosen for the study had a lower set of mechanical properties [18], it is possible to notice that best results received with nanodispersed carbonate calcium introduction surpass the original material on 20 % and at the introduction of PTP on 32 %.…”

Light-cured dimethacrylate dental restorative composites under a prism of annihilating positrons

“…[14][15][16][17][18][19][20][21] Under such analysis (arranged as constraint-free decomposition [14][15][16][17][18][19][20] or partially-constrained decomposition fixing the shortest τ 1 lifetime 14,15,21 ), the 3 rd component with a long-lived lifetime τ 3 is ascribed to o-Ps annihilation in free-volume holes (voids), the 2 nd component with an intermediate lifetime τ 2 is due to free positron annihilation in interfacial free volumes or other defect states mainly in a solid phase, and the 1 st component with the shortest lifetime τ 1 is attributed to p-Ps self-annihilation conjugated with reduced e + annihilation from defect-free bulk state. [4][5][6] The lifetime-fixing fitting is preferred to overcome inadequacy in the resolving of the shortest component due to mixing different annihilation events (especially, when I 1 intensity occurs to be substantially greater than I 3 ).…”

“…In case of stronger input from Ps decaying in the x3-term decomposed PAL spectrum (as for many nanocomposites 5,9,[14][15][16][17][18][19][20][21] ), the e + -trapping can be defined in terms of a simple trapping model assuming 2 additive inputs arise from trapped e + and decayed o-Ps states. 22 This model with 2 additive e + -trapping defects with κ d1 and κ d2 annihilation rates defined as …”

“…[24][25][26] Within a x4-fitting route assuming fixed τ 1 value, the 4 th component was ascribed to o-Ps annihilation in the main part of the polymer matrix, while the 3 rd was explained as arising from o-Ps annihilation in the filler-matrix interphase. With re- [16][17][18][19] Recently, some current authors have shown that x4-fitting assuming fixed shortest lifetime (τ 1 = 0.125 ns) was also favorable for dimethacrylate DRC subjected to long-term aging, which were initially characterized by x3-decomposed best-fitted PAL spectra. 20,27 The origin of the additional component in o-Ps decaying in these polymer/filler DRC was not clarified unambiguously, while a version on stress-inducing destruction through growing inner and surface cracks seems quite plausible.…”