TiO2-encapsulating PVC capable of catalytic self-suppression of dioxin emission in waste incineration as an eco-friendly alternative to conventional PVC

Here, we describe the preparation of TiO2-encapsulating poly(vinyl chloride) (TEPVC), and demonstrate the potential applicability of the material as an eco-friendly alternative to conventional PVC. In particular, TEPVC shows lower emission of toxic chemicals upon waste incineration compared to PVC, owing to the catalytic oxidation and decomposition of such chemicals by the encapsulated TiO2 nanoparticles. Surface-modified TiO2 nanoparticles (M-TiO2) are used for the preparation of TEPVC to facilitate the uniform dispersion of monomeric TiO2 in the initial reaction mixture, which is the key to the preparation of a final TEPVC showing a high dispersion of functional TiO2 nanoparticles in the PVC matrix, without significant agglomeration. The content of encapsulated M-TiO2 in TEPVC was determined to be approximately 0.93 wt%, and the high dispersity of M-TiO2 minimizes PVC deterioration, as determined by examinations of morphology, and thermal and mechanical properties. The emission levels of toxic chemicals upon incineration of TEPVC and unmodified PVC samples were analyzed by gas chromatography with high-resolution mass spectrometric detection, using internal standards composed of 13C-labeled congeners of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls. The levels of toxic chemicals produced by incineration of TEPVC were 50% of those seen after unmodified PVC incineration; the sum of toxic equivalent values of all toxic chemicals generated from the incineration of TEPVC was thus only half that seen after incineration of unmodified PVC.

Figure optionsDownload as PowerPoint slideResearch highlights
► Incorporation of nanosized catalyst within PVC via typical suspension polymerization.
► Minimized PVC deterioration owing to high dispersity of TiO2 nanoparticles.
► Self-suppression of dioxin emission by catalytic activity of TiO2 incorporated in PVC.
► Halved dioxin emission by 0.93 wt% of incorporated TiO2 during incineration at 700 °C.
► PVC–catalyst nanocomposite as an eco-friendly alternative to conventional PVC.