Dielectric properties of poly vinyl acetate (PVAC) wood glue
The values for the relative dielectric constant I have seen (Internet) vary from about 3 to 15, with unknown loss factor. I would like to use it as insulation/coating in an experiment (instead of a 2-component epoxy resin). Operating frequency will be around 100 kHz. I am planning to use the water resistant variety (D3).
don't know the actual dielectric constant, but I know for a fact that it will absorb 2.45 GHz energy, similar to water, when it is uncured. I would assume it would NOT absorb energy at 100 KHz, due to the long wavelength and the short molecule size.
Hello Biff44,
The bad RF properties of uncured glue enables efficient RF drying in the wood industry. In my application it will be fully cured (with low moisture content). Those PVAc glues do contain other components that may affect electrical properties, so I have no idea about tandelta at 100 kHz.
Probably I have to prepare a sample and measure it myself, unless somebody has some data available.
Hello Biff44,
Bad news about the PVAc wood glue properties:
Today I prepared two sheet capacitors with 1 cm^2 area and dielectric thickness of 0.6 mm. One sample using polyethylene and one using fully cured PVAC wood glue impregnated cotton cloth. Both have sufficient creepage distance.
The PE sample showed no significant heating under 2 kVp, 90 kHz. Visible corona discharge at the capacitor edges only (because of the thin capacitor plates).
The PVAC/cotton sample absorbed > 20W under 1kVp, 90kHz. Within a second or two, full breakdown occurred (with light, smoke, audio, etc), experiment terminated.
To be honest, I tried the PVAC sample with 2kV first. However everything went too fast to make a useful observation.
My simple conclusion after one day of preparing the setup: PVAc D3 wood glue is useless for insulation purposes in (experimental) power conversion applications under high E-field strength.