Electrical properties of polymers

Electrical response and functionality of polymer matrix-titanium carbide composites

“…The main dielectric loss peak, which is recorded in the dielectric spectra of all specimens in the intermediate frequency region, is now formed in the vicinity of 55°C for the unfilled epoxy resin, and a few degrees lower in the case of the composite systems, at f = 0.1 Hz in Figure 7a. In dielectric loss versus temperature spectra is a rule of thumb to determine glass transition temperature from the position of the relative loss peak (α-relaxation process) at constant frequency equal to 0.1 Hz [16][17][18][19]. Derived value for glass transition temperature, via DSC measurements, of pure polymer matrix (56.6°C) appears to be very close with the position of loss peak in Figure 7a, supporting further the assignment of this process to glass to rubber transition of the epoxy resin.…”

Measurement method and apparatus for monitoring the kinetics of polymerization and crosslinking reactions by microwave dielectrometry

“…This performance can be determined by measuring the overall frequency stability affected by both long-(temperature drift) and shortterm (noise of the frequency locking loop) effects. The frequency stability has been evaluated by measuring the resonance frequency in the band 1.7 X lop3- 1 Hz, where only long-term effects are effective (Fig. 5).…”

“…Inside the cavity some boundary conditions for the microwave electric field have to be verified and all the shapes of the items placed inside the cavity must be matched with the electric field distributions in order that eqs. (1) may hold. In the right cylindrical TEoll cavity we have employed, all shapes must have cylindrical symmetry with the axis lying on the axis of symmetry of the cavity.…”

Thermal, Mechanical, Electrical and Morphological Characterization Studies of Poly(vinyl chloride) Blends with Various Polyitaconates and Block Copolymers of Polyitaconates/Poly(dimethyl siloxane)

“…This is rather likely, as the aggregates behave like crystallites in which either ferroelectric cancellation of the moments or cancellation through intermolecular and intramolecular hydrogen bonding is more probable than at the surface and in the inter-aggregate space. [28] On the other hand, it is a well known fact for PVC that the addition of small amounts of some plasticizers, up to about 10% (amounts comparable with those used in this work) can have unplasticizing effect, as well. [28] The results given in Table 4 indicate some differences in behavior of PVC and its blends with homo-and blockcopolymers.…”

“…[28] On the other hand, it is a well known fact for PVC that the addition of small amounts of some plasticizers, up to about 10% (amounts comparable with those used in this work) can have unplasticizing effect, as well. [28] The results given in Table 4 indicate some differences in behavior of PVC and its blends with homo-and blockcopolymers. The addition of about 1% polyitaconates (PMBI or PMCHI) or addition about 1-3% block copolymers containing PDMS blocks have plastisizing effect on PVC.…”