Preparation and Properties of Poly(propylene carbonate) and Nanosized ZnO Composite Films for Packaging Applications Jongchul Seo, 1 Gwonyoung Jeon, 1 EUi Sung Jang, 2 Sher Bahadar Khan, 2,3 Haksoo Han 2 1 Department of Packaging, Yonsei University, 234 Maeji-ri, Heungup-myun, Wonju-si, Kangwon-do 220-710, Korea 2 Department of Chemical and Biomolecular Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749, Korea 3 Centre for Advanced Materials and Nano-Engineering (CAMNE) and Department of Chemistry, Faculty of Sciences and Arts, Najran University, P. O. Box 1988, Najran, 11001, Kingdom of Saudi Arabia Received 6 July 2010; accepted 25 January 2011 DOI 10.1002/app.34248 Published online 20 May 2011 in Wiley Online Library (wileyonlinelibrary.com). ABSTRACT: A series of polypropylene carbonate (PPC)/ ZnO nanocomposite films with different ZnO contents were prepared via a solution blending method. The mor- phological structures, thermal properties, oxygen perme- ability, water sorption, and antibacterial properties of the films were investigated as a function of ZnO concentration. While all of the composite films with less than 5 wt % ZnO exhibited good dispersion of ZnO in the PPC matrix, FTIR and SEM results revealed that solution blending did not lead to a strong interaction between PPC and unmodified ZnO. As such, poor dispersion was induced in the compos- ite films with a high ZnO content. By incorporating inor- ganic ZnO filler nanoparticles, the diffusion coefficient, water uptake in equilibrium, and oxygen permeability decreased as the content of ZnO increased. The PPC/ZnO nanocomposite films also displayed a good inhibitory effect on the growth of bacteria in the antimicrobial analysis. The enhancement in the physical properties achieved by incorpo- rating ZnO is advantageous in packaging applications, where antimicrobial and environmental-friendly properties, as well as good water and oxygen barrier characteristics are required. Furthermore, UV light below  350 nm can be efficiently absorbed by incorporating ZnO nanoparticles into a PPC ma- trix. ZnO nanoparticles can also improve the weatherability of a PPC film. In future research, the compatibility and disper- sion of the PPC matrix polymer and the inorganic ZnO filler nanoparticles should be increased. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 1101–1108, 2011 Key words: polypropylene carbonate; ZnO nanoparticles; water sorption; antibacterial property; packaging materials; morphological structure INTRODUCTION The utilization of carbon dioxide has attracted scien- tific and practical interest in recent years because of environmental pollution and energy shortages. 1–3 Global warming, also known as the greenhouse effect, is primarily caused by the massive release of carbon dioxide into the atmosphere. The contribution of car- bon dioxide to global warming is estimated to be about 66%. Thus, the incorporation of carbon dioxide into materials has attracted a great deal of interest as a means to reduce greenhouse gas pollution and is viewed as an alternative to overcome shortages in conventional petroleum fuel supplies. Among the polymeric materials that use carbon dioxide, polypropylene carbonate (PPC) was first syn- thesized by Inoue and Tsuruta via the copolymeriza- tion of carbon dioxide and propylene oxide. 4 PPC is a biodegradable aliphatic polycarbonate that can be degraded to H 2 O and carbon dioxide. The synthesis of PPC allows for carbon dioxide to be recycled in the environment. PPC has interesting chemical and physi- cal properties, such as compatibility, impact resist- ance, translucence, and innocuousness. Such proper- ties are advantageous in adhesives, solid electrolytes, barrier materials, plasticizers, and new materials for packaging applications. Much research has been devoted to improve the thermal and mechanical prop- erties of PPC by blending it with other polymers 5–7 or inorganic fillers. 8–11 Because of the nanoscale sizes and large specific surface areas of nanosized fillers, the interfacial interaction between the filler and the polymer is strong, resulting in a large improvement in the Correspondence to: H. Han (hshan@yonsei.ac.kr). Contract grant sponsor: National Research Foundation of Korea (MEST); contract grant number: (NRF-2009- C1AAA001-0092926). Contract grant sponsor: New and Renewable Energy R and D Program, Ministry of Knowledge Economy, Repub- lic of Korea; contract grant number: 2009T100100606. Journal of Applied Polymer Science, Vol. 122, 1101–1108 (2011) V C 2011 Wiley Periodicals, Inc.