If you want to use film as an infrared filter, you need to use developed color film. Whether it should be unexposed or exposed depends on whether it is slide or negative film. Regardless, you should not expect great image quality with these materials because they were not designed to be used as filters. Using developed film as an IR-pass filter is just a cheap way to experiment.

Considering that mirrors reflect UV and IR, I would expect the silver in black and white, as well as undeveloped color, film to block both visible and infrared light from passing through. The silver in color films is washed away during the development process.

Another issue is that refraction of light through film is likely different from the glass filter you removed. This would affect the camera's ability to focus.

As for the purple tint, I suspect the dyes in film block light only to around 600nm because I am still able to see through it. Standard IR-pass filters block to about 720nm. The longer the wavelength, the more monochromatic your images should appear.

Note the response of the sensor to blue between 650nm and 720nm:

If you intend to continue taking infrared photos, you should get a glass IR-pass filter. They are fairly inexpensive. You can replace the IR-cut filter in your camera with plain glass or just leave it out entirely, if your camera can focus without it.