Surface characteristics of chemically modified newsprint fibers determinedby inverse gas chromatography

The surface characteristics of treated waste newsprint fibers were investig ated using inverse gas chromatography (IGC). The surfaces of waste newsprin t fibers were modified with gamma-aminopropyltriethoxysilane, dichlorodieth ylsilane (DCS), phthalic anhydride (PA)I and maleated polypropylene. The ef fectiveness of these surface treatments was monitored by the IGC adsorption curves using n-alkanes and acid-bar probes. The empirical acid (K-A) and b ase (K-D) characteristics (i.e,, electron donor/acceptor abilities) of untr eated and treated newsprint fibers Here determined using Schultz's method a nd were correlated with the surface chemical compositions determined from X -ray photoelectron spectroscopy and Fourier transform infrared spectroscopy . The results indicated that the surface of untreated newsprint fibers had an acidic characteristic due to the electron acceptor character of the hydr oxyl protons. The newsprint fibers reacted with phthalic anhydride or malea ted polypropylene also exhibited an acidic surface behavior attributed to p endent carboxylic groups. Dichlorodiethylsilane produced a strong acidic su rface attributed to the highly electronegative nature of the chlorine atoms of dichlorodiethylsilane. However, when the fibers were reacted with gamma -aminopropyltriethoxysilane, the basic characteristic (electron donor abili ty) of the fiber surface wets increased, presumably by the presence of atta ched amino groups.