| 학회 | 한국고분자학회 |
| 학술대회 | 2005년 가을 (10/13 ~ 10/14, 제주 ICC) |
| 권호 | 30권 2호 |
| 발표분야 | 기능성 고분자 |
| 제목 | A Novel Approach to Preparation of TiO2 Nanoparticle Well-Dispersed Poly(vinyl chloride) (PVC). 1. Photocatalytic Degradation of PVC/TiO2 Nanohybrid |
| 초록 | Photocatalytic degradation of poly(vinyl chloride) (PVC) using titanium dioxide (TiO2) has been investigated as an eco-friendly alternative strategy to the current landfill and toxic byproduct-emitting incineration of PVC wastes1. The present study intends to present a novel idea to well disperse TiO2 nanoparticles in PVC polymer, aiming at a breakthrough of the unresolved problem in the conventional PVC/TiO2 composites related with the poor dispersion of the nanoparticles in the polymer matrix. For the purpose of this, TiO2 nanoparticles are prepared by a sol-gel process, and the size of the particle is determined to be about 5~10 nm in diameter from transmission electron microscopy (TEM) and dynamic light scattering (DLS). Next, hyperbranched poly(ε-caprolactone) (HPCL) with numerous COOH groups is prepared from moisture-sensitive catalyst-free polymerization of 2,2-bis[ω-hydroxy oligo(ε-caprolactone) methyl]propionic acids followed by modification reaction using pyridinium dichloromate (PDC), then characterized with 1H-NMR and 13C-NMR analyses. In this study, the HPCL with many function groups and potential to be an excellent substitute for PVC plasticizer is used as binder molecules to disperse TiO2 in PVC. The integration of TiO2 nanoparticles onto HPCL is carried out by a dip-coating method based on self-assembly between TiO2 nanoparticle and the COOH group of HPCL, and the loading of the nanoparticles in the TiO2-intergrated HPCL (HPCL-TiO2) is determined to be ca. 3.3 wt% by using X-ray photoelectron spectroscopy (XPS). The HPCL-TiO2 is blended with PVC through solution blending in THF as solvent. Then, the degree of dispersion of TiO2 nanoparticles in the resulting PVC/HPCL-TiO2 (60/40) is evaluated by field emission scanning electron microscopy (FESEM) equipped with energy dispersive spectrometry (EDS). The FESEM/EDS image of the PVC/HPCL-TiO2 shows that the TiO2 nanoparticles are well-dispersed in PVC matrix, while some agglomerates are observed in that of PVC/TiO2, which are prepared from the solution blending with TiO2 instead of HPCL-TiO2. The photocatalytic degradation of the samples are examined and verified from the formation of cavities in the surface of the films after UV irradiation (그림1). The number of holes in the PVC/HPCL-TiO2 nanohybrid increases with the irradiation time, but no large hole is observed in the neat PVC/HPCL under the same UV exposure. This fact demonstrates that the PVC/TiO2 nanohybrid is efficiently decomposed by the photocatalytic reaction of the incorporated TiO2 nanoparticles. In addition to microscopic analysis, positron annihilation lifetime spectroscopy (PALS) is also performed as a new tool to characterize the molecular-level structural changes accompanied with the photocatalytic degradation of PVC/TiO2 nanohybrid. The PALS study demonstrates a crucial complementary evidence for the accelerated degradation of PVC/HPCL-TiO2 not only in the microscopic level but also in the molecular-level. Fig. 1. FESEM micrographs of PVC/HPCL-TiO2 after 0 day and 30 day UV illumination and that of PVC/HPCL after 30 day UV exposure. 참고문헌 1) H. Hidaka, Y. Suzuki, K. Nohara, S. Horikoshi, Y. Hisamatsu,; E. Pelizzetti,; N. Serpone, J. Polym. Sci., 34, 1311 (1996). |
| 저자 | 김성호, 곽승엽 |
| 소속 | 서울대 |
| 키워드 | PVC/TiO2 Nanohybrid; TiO2 Nanoparticle; Photocatalytic Degradation |
