抄録
To clarify the relationship between the surface chemical properties of ethylene-vinyl alcohol (EVA) or ethylene-vinyl acetate copolymer (EVAc) and copolymer composition, the ζ-potentials of EVA and EVAc were measured by using the streaming-potential method.
The following results were obtained:
1) The ζ-potentials of heat treated polyethylene (PE) and polyvinyl alcohol (PVA) are -155mV, -35mV respectively. The ζ-potentials of EVA and EVAc are closely related to its water adsorption.
2) The ζ-potentials of EVA closely depend upon its VA content and do not change gradually, but give a sudden turn of chemical properties from that of PE to that of PVA at about VA 40 mol%.
3) The ζ-potential of EVAc decreases rapidly from that of PE to that of PVAc until EVAc becomes amorphous at about 21 mol%.
4) The relationships between the ζ-potentials of EVA and EVAc and copolymer composition are explained on the basis of the surface energy, especially the hydrogen bonding force component and the adsorption ability of OH- ions from solution phase.
