Printing Properties of Water-based Pigmented Inkjet Inks on the Oxygen-plasma Modified Polylactide Sheets 238 The Journal of the Royal Institute of Thailand Vol. 37 No. 1 Jan.-Mar. 2012 Boonchoat Paosawatyanyong is an Assistant Professor. He works at Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok, Thailand. He obtained his B.Sc. in Physic, from the Faculty of Science, Chulalongkorn University, and his M.Sc. and Ph.D. degree in Physics and Electrical Engineering, respectively, from Michigan State University, U.S.A., in 1998. His research interests are in the areas of plasma physics and technology, nanotechnology, solid state devices and applications, polymer synthesis and modification by plasma. He is a member of ThEp Center, CHE. Boonchoat Paosawat- yanyong has contributed research articles to many ISI journals and can be contacted at paosawat@ sc.chula.ac.th . Suda Kiatkamjornwong is currently a Full Professor (A 1) of Polymer Science and Engi- neering at the Department of Imaging and Printing Technology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand. She obtained her B.Sc. and M.Sc. degrees in Chemistry and Physical Chemistry, respectively, from the Faculty of Science, Chulalongkorn University, and her Ph.D. degree in Polymer Science and Engineering from Lehigh University, USA, in 1983. Her research interests are in the areas of superabsorbent polymers, imbiber beads, modification of green polymers, digital printing and environment in polymers and printing. Suda Kiatkamjornwong is the corresponding author of many articles in ISI journals and can be contacted at firstname.lastname@example.org .