INFLUENCE OF PLASMA TREATMENT ON THE MOLAR-MASS OF POLY(ETHYLENE-TEREPHTHALATE) INVESTIGATED BY DIFFERENT CHROMATOGRAPHIC AND SPECTROSCOPICMETHODS

The influence of different types of low and atmospheric pressure plasm a on poly(ethylene terephthalate) (PET) has been studied in terms of c hanges in molar mass and molar mass distribution. Apart from a variati on of plasma gases (oxygen, helium) different types of plasma (microwa ve, radio frequency, corona discharge) were used for the plasma surfac e modification. The changes in molar mass and types of functional end groups of lower molar mass products were investigated by means of matr ix-assisted laser desorption/ionization time of flight mass spectromet ry (MALDI-TOFMS), whereas the high-molar mass fraction was analyzed by means of size-exclusion chromatography (SEC). The formation of crossl inked products during exposure to a helium plasma, which emits prepond erately energy-rich and intense ultraviolet radiation, was proved by m eans of thermal field-flow fractionation (ThFFF). This method combined with a multiangle laser light scattering (MALLS) detector allows dete ction of weakly crosslinked polymers and microgels. (C) 1998 John Wile y & Sons, Inc.