Guirguis, O. W., and M. T. H. Moselhey, "Optical study of poly(vinyl alcohol)/hydroxypropyl methylcellulose blends", Journal of Materials Science, vol. 46, no. 17: Springer US, pp. 5775-5789, 2011. AbstractCU-PDFWebsite

The proposal in this study was to evaluate the optical properties of different biopolymers films. The materials used were poly(vinyl alcohol) (PVA) and hydroxypropyl methylcellulose (HPMC). PVA/HPMC blends were prepared by casting technique. Variations in the group coordination in the infrared region were followed. The effects of HPMC concentrations on the optical properties of the PVA films were studied by near infrared, ultraviolet/visible, transmittance, and reflectance in the spectral region 200–2500 nm. Absorption, transmittance, and reflectance spectra were used for the determination of the optical constants. The study has been also extended to include the changes in the optical parameters including the band tail width and band gap energies and extinction coefficient for the investigated films. The results indicate that the optical band gap was derived from Tauc’s extrapolation and decreases with the HPMC contents. The obtained optical parameters were found to be strongly affected by HPMC contents.

Guirguis, O. W., M. A. F. H. Elkader, and A. A. Nasrat, "Enhancing antimicrobial activity for chitosan by adding Jojoba liquid wax", Materials Letters, vol. 93, pp. 353 - 355, 2013. AbstractCU-PDFWebsite

The purpose of the present study is to enhance the antimicrobial activity of chitosan. For this reason, thin films of chitosan incorporated with different concentrations of Jojoba liquid wax (JLW) were prepared by using the casting technique. The agar disc diffusion method was used to investigate the antimicrobial activity of the films against two different microorganisms namely Staphylococcus aureus and Bacillis subtilis. The results indicated that as the concentration of \{JLW\} increases the antimicrobial activity for S. aureus and B. subtilis increases. Moreover, it is found that the minimum inhibitory concentration (MIC) values for both systems decrease by increasing the amount of the antimicrobial agent Jojoba with chitosan. In conclusion, the data obtained reveal that chitosan has a great potential to improve its antimicrobial activity by incorporating with antimicrobial agent.