Metallized polyimide films with high reflectivity and electroconductivity - Polyimides and Other High Temperature Polymers - page 392

In Fig. 1 are presented IR-spectra of PAA2 film (curve 1) and hydrolysed
PAA2 film in 1% KOH aqueous solution (curve 2). We see that hydrolysis of
PAA2 film gives the same characteristic bands in infrared as of polyamate struc-
ture of PI based on PMDA and ODA as described in the literature [22]: formation
of carboxylate structure, i.e., displacement of 1408 cm -1 (carbonyl) band to 1420
cm -1 (carboxylate), bands of amide I (ν = 1680 cm -1 , 1670 cm -1 ) which shifts to
1660 cm -1 , 1650 cm -1 and band of amide II (ν = 1590 cm -1 ) which shifts to 1575
cm -1 . The results of the investigation of duration of alkali treatment of PAA2 film
on potassium content is presented in Fig. 2. It is seen that hydrolysis of PAA2
film proceeds for 30 minutes and achieves practically 100% conversion.
Exchange of K + ions with the transition metals takes place following the hy-
drolysis in aqueous metal salt solution. The spectra of chelated PAA2 films
(curves 3 and 4, Fig. 1) are practically the same as for PAA2/K + except a shift of
NH vibration bands (ν = 3330 cm -1 to 3290 cm -1 ) which points towards the for-
mation of ion-coordination complexes between the NH group of PAA2 potassium
salt and the metal cation.
Determination of copper content in the film in the process of ion exchange
shows that exchange of K + by Cu 2+ cations proceeds nearly with 100% conversion
(Fig. 2). This process suggests that there is no need to convert polyamate structure
into poly(amic acid) one by additional step of acidic treatment followed by metal
loading [20].
Figure 2. Content M (mg-equivalent/g) of potassium (•) and copper (o) in PAA2 film as a function
of treatment duration.