EFFECT OF THE CHEMICAL FORM OF THE ADDITIVES IN POLY(VINYL CHLORIDE) AND POLY(ETHYLENE) MATERIALS ON LASER-ABLATION EFFICIENCY USING INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY

The application of Laser Ablation Inductively Coupled Plasma Atomic Em ission Spectrometry to the direct determination of additives in polyme ric materials has been studied. A Nd:YAG laser, operating at both infr ared (1064 nm) and UV (266 nm) wavelengths, has been used with a beam masking and a beam expander device for solid sampling of poly(vinyl ch loride) (PVC) and poly(ethylene) (PE) materials. Emphasis was placed o n the influence of the chemical structure of the elements to be determ ined and of the polymer matrix on laser ablation efficiency. Several s amples of PVC and PE were produced by compounding Ca-, Sn- and Ti-base d additives in the basic resins. In both polymers, the three elements were incorporated either as inorganic compounds, as organometallic com pounds, or as a mixture of the two former structures. It has been show n that the signal-to-concentration ratios of the elements studied were strongly dependent on (i) the chemical structure of the elements in t he additives used, (ii) the nature of the polymer matrix, and (iii) th e interactions between additives, and between additives and the polyme r. The carbon line was not sufficiently efficient to compensate for th ese effects, and the modification of the laser operating parameters di d not affect significantly the ablation process. The results presented in this work pointed out the need to match matrix samples and standar ds to achieve reliable quantitative analysis of polymers. (C) 1997 Els evier Science B.V.