PE, that's not the enzyme. It's something else but I'm not going down that road anyway.

Here's a link to the paper I found http://dl.dropbox.com/u/4212013/Surf..._stability.pdf

It's entitled Surface structure and properties of poly-(ethylene terephthalate) hydrolyzed by alkali and cutinase, written by Ilaria Donelli, Giuliano Freddi, Vincent A. Nierstrasz, Paola Taddei, and published in a journal called Polymer Degradation and Stability. Hopefully anyone interested can open the link. Let me know if it doesn't work.

Besides plenty of things I don't quite understand, there are two things of interest in this paper regarding the treatment of PET.

1) A treatment protocol is given,

For the alkaline treatment, PET films were immersed in a 1M NaOH aqueous solution at 40 C, for different times, from 30 min to 24 h, under agitation on a shaking bath (Isco SBH/D, 110 rpm/min). Afterwards, membranes were extensively washed with distilled water and dried at room temperature overnight.
So here they tell us the concentration of NaOH, temperature and process. I am making the assumption that since these fellows are associated with the fabric and dye industry, they are citing a standard method of processing.

2) The maximum necessary treatment time using the author's protocol is two hours,

Interestingly, both NaOH and cutinase (the ezyme being compared Ed) lead to a levelling of the WCA values which do not change too much for treatment times longer than 2 h.
WCA stands for water contact angle and refers to the amount of water beading displayed by the PET. The higher the WCA, the more beading. We want a low WCA.

I am treating a new piece of Dura-lar now according to the information from this paper and I'll report back when I get some new results.

-- Jason