Dh. Gracias et al., A study of the glass transition of polypropylene surfaces by sum-frequencyvibrational spectroscopy and scanning force microscopy, CHEM PHYS, 245(1-3), 1999, pp. 277-284
Sum-frequency generation (SFG) vibrational spectroscopy and scanning force
microscopy (SFM) were used to probe structural changes of atactic polypropy
lene (APP) and isotactic polypropylene (IPP) surfaces in the glass transiti
on. The results indicate that below the glass transition, the surface polym
er chains are better oriented with the CH2 groups pointing outward and the
surface elastic modulus is higher. The SFG and SFM results correlate well i
n the transition towards the glass phase. No discernible difference between
the glass transition temperatures of the bulk and surface was observed. (C
) 1999 Elsevier Science B.V. All rights reserved.