Acrylics electrical

Process. Any standard precursor material can be used, but the preferred material is wet spun Courtaulds special acrylic fiber (SAF), oxidized by RK Carbon Fibers Co. to form 6K Panox B oxidized polyacrylonitrile (PAN) fiber (OPF). This OPF is treated ia a nitrogen atmosphere at 450—750°C, preferably 525—595°C, to give fibers having between 69—70% C, 19% N density less than 2.5 g/mL and a specific resistivity under 10 ° ohm-cm. If crimp is desired, the fibers are first knit iato a sock before heat treating and then de-knit. Controlled carbonization of precursor filaments results ia a linear Dow fiber (LDF), whereas controlled carbonization of knit precursor fibers results ia a curly carbonaceous fiber (EDF). At higher carbonizing temperatures of 1000—1400°C the fibers become electrically conductive (22). 

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Polycarbonate It is a tough, transparent plastic that offers resistance to bullets and thrown projectiles in glazing for vehicles, buildings, and security installations. It with stands boiling water, but is less resistant to weather and scratching than acrylics. It is notch-sensitive and has poor solvent resistance in stressed molded products. Use includes coffee makers, food blenders, automobile lenses, safety helmets, lenses, and many nonburning electrical applications. 

With regard to the composition of the electrical effects, values of pj for the sets studied are reported in Table XIV. The sets in which the hydroxyl group is the reaction site generally exhibit a Pr value of about 39. The cis-3-substituted acrylic acids show a p value of 39 in aqueous solution. The value of 71 obtained in 50% aqueous ethanol seems too large. 

Data are extant in the literature for two other sets of ethynylene compounds. The sets studied are reported in Table XXXIII. Results of correlation are set forth in Table XXXIV and values of Pr in Table XXXV. The ionization constants of 3-substituted propiolic acids, which were first correlated with the Hammett equation by Charton (18), gave an excellent correlation with eq. (2) (set 22-27-1). The results are very much improved by the elimination of the value for X = H (set 33-27-2). The composition of the electrical effect corresponds approximately to that of the Op constants. The magnitude of the electrical effect is significantly less than that observed for the rrans-3-substituted acrylic acids. 

Liquid crystalline elastomers (LCEs) are composite systems where side chains of a crystalline polymer are cross-linked. Their mesogenic domains can be ordered nematically and undergo a phase transition to a disordered state at a temperature well above the glass-transition temperamre (Tg) of the polymer. Although the phase transition is thermally driven, LCEs demonstrate electrical conductivity and thus can be electrically stimulated." Ratna" has reported contractions of nearly 30% due to the phase transition of acrylate-based LCEs. 

Polyvinyl chloride has been modified by photochemical reactions in order to either produce a conductive polymer or to improve its light-stability. In the first case, the PVC plate was extensively photochlorinated and then degraded by UV exposure in N2. Total dehydrochlorination was achieved by a short Ar+ laser irradiation at 488 nm that leads to a purely carbon polymer which was shown to exhibit an electrical conductivity. In the second case, an epoxy-acrylate resin was coated onto a transparent PVC sheet and crosslinked by UV irradiation in the presence of both a photoinitiator and a UV absorber. This superficial treatment was found to greatly improve the photostability of PVC as well as its surface properties. 

Table 1 Deformation of Poly(sodium acrylate) Gel in Electric Fields...

Conductive blacks, 4 775, 799-800 Conductive coatings, 4 712-713 Conductive energy flux, 25 275-276 Conductive fibers, acrylic, 44 219 Conductivity, 46 512. See also Electrical conductivity... 

General Electric Co.) were added to the acrylic and epoxy monomers, respectively, to initiate photopolymerization. The acrylic monomers that polymerized by a free-radical mechanism were irradiated under nitrogen. The output of the lamp measured at the substrate was about 4 mW/cm2 at 260 nm and about 11 mW/cm2 at 310 nm. 

Figure 9. Schematic representation of the acrylic chambers used for treatment of P815 cells with DC. Chambers are connected in series by filter-paper bridges, and fitted with platinum electrodes in their extremities. In this system, cell suspensions can be exposed directly to the anodic reactions (AC) or cathodic reactions (CC) or to electric current without contact with the electrodes, in the intermediary chamber (IC). Internal volume 3 cm3. After Veiga et al.62...

Acrylics are good insulators even in wet environments, with high dielectric resistivities and moderate loss factors. Special grades are marketed for electrical applications. 

Figure 3.25 — Electrolytic flow-cell of the tubular type. (A) Whole cell. (B) Detail of working micro-electrode 1 Working electrode 2 reference electrode (Ag/AgCl) 3 counter-electrode (Pt wire) 4 acrylic tube 5 rubber cup 6 electrolyte solution (mobile phase) 7 fused-silica tube (50- or 100-/tm ID) 8 Ni wire (diameter 25 or 50 im, length 5 mm) 9 PTFE tube (0.1-mm ID, 2-mm OD) 10 hole 11 adhesive resin 12 glass pipette 13 silver paste 14 insulator 15 electric wire, (Reproduced from [184] with permission of Elsevier Science Publishers).

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