COATING Nordic Pulp & Paper Research Journal Vol 29 no (4) 2014 741 Novel coating of bagasse paper sheets by gelatin and chitosan Mona Abdelkader Nassar, Mohamed El-Sakhawy, Hassan M. F. Madkour, Ahmed K. El-ziaty and Salah A. Mohamed KEYWORDS: Coating, Bagasse, Paper sheets, Barrier properties, Mechanical properties, Chitosan, Gelatin SUMMARY: The increasing need to improve end-user specifications of paper encourages studying of coating bagasse-based paper with chitosan and gelatin in order to acheive good mechanical and barrier properties. The effect of different concentrations of gelatin (0.5-2.5%) on mechanical properties (breaking length, burst index and tear index) of bagasse paper sheets was studied. Also, paper sheets were coated by impregnation in different concentrations of chitosan solution (0.2-2%). Paper coatings using coating blends from 2% gelatin solution containing 0.5% glycerol and 1% chitosan were studied in ratios of 1:0, 3:1, 1:1, 1:3 and 0:1 gelatin/glycerol: chitosan. Air permeability and mechanical properties of coated paper was studied. Scanning electron microscope study indicates that the distribution of gelatin/glycerol/ chitosan onto the coated paper is uniform. In general, both water-soluble gelatin and chitosan coatings had a positive impact on the final properties of the coated paper. ADDRESSES OF THE AUTHORS: Mona Abdelkader Nassar 1 (monanassar_65@yahoo.com), Mohamed El- Sakhawy 2 (elsakhawy@yahoo.com), Hassan M. F. Madkour 3 (fawzyhassan@ymail.com), Ahmed K. El- ziaty 3 (ahm512@sci.asu.edu.eg) and Salah A. Mohamed 1 (salahazhar1@yahoo.com): 1: National Research Center, Packing and Packaging department, Tahrir St.,Dokki, Cairo Egypt. 2: Cellulose and Paper Department, National Research Center, Egypt. 3: Chemistry Department, Faculty of Science, Ain Shams University Cairo, Egypt. Corresponding author: Mona Abdelkader Nassar Fibre-based packaging materials have many advantages over the plastic candidates such as renewability, recyclability and compostability. However, their application is restricted due to poor barrier properties and high sensitivity to moisture. In order to improve the barrier properties, packaging material is laminated with aluminium or petroleum based polymers such as PE (polyethylene), EVOH (ethylene vinyl alcohol) and PVC (polyvinyl chloride). Since both the plastic film and the aluminium are problematic for sorting, recycling and recovery, replacing one or more barrier layers thereof in demanding packaging with bio-based polymers should be much desired from the environmental point of view (Du et al. 2014; Hult et al. 2013). Biopolymers have been evaluated for packaging applications such as chitosan, (Kjellgren 2006; Reis et al. 2011), gelatin (Liu et al. 2012), alginate and caseinate (Aloui et al. 2011), microfibrillated cellulose (Aulin et al. 2010; Lavoine et al. 2014) and esterified lignin (Hult et al. 2013). Gelatin has been extensively studied for its film-forming capacity and applicability as an outer covering to protect food. Fish gelatins may be a good alternative to synthetic plastics for making films to preserve foodstuffs. Moreover, it is one of the first materials proposed as a carrier of bioactive components. Sorbitol and glycerol are the plasticizers most commonly used in producing gelatin-based films (Gómez-Guillén et al. 2009). Gelatin is used for surface sizing and for coating purposes either alone or with other adhesive materials (Mansour et al. 2001). The gelatin coating creates a smooth surface by filling up the small surface imperfections thereby ensuring improved printing reproduction. The blending of fish gelatin with other biopolymers, such as chitosan, is one possible way to improve the properties of fish gelatin (Rivero et al. 2009). Chitosan is derived from chitin, and it is structurally a type of polysaccharide similar to cellulose, which is widely present in nature as a linear polysaccharide composed mainly of β-(1-4) D-glucosamine repeating structures. Chitosan is known to be non-toxic and odorless; so much interest has been paid to its industrial applications in the past decade (Dutta et al. 2004). Due to excellent antimicrobial property, chitosan film may be used in food packaging (Dutta et al. 2004; Arancibia et al. 2014). It was found that chitosan coating could be used as a fat barrier, but treatment cost remained high compared with fluorinated resins. In an attempt to decrease both of treatment cost and fat transfer, other natural molecules such as cellulose ethers and alginates were included with chitosan in the coating formulations (Ham-Pichavant et al. 2005). Beeswax–chitosan emulsion was coated on paper surface to improve its water vapor barrier and water resistance properties (Zhang et al. 2014). Chitosan and its derivatives, cyanoethyl and carboxymethyl chitosan, are used as additives to cellulose fiber during the formation of paper sheet or as a solution in which the paper sheet is dipped (Nada et al. 2006; Fernandes et al. 2010; Nicu et al. 2013). The incorporation of chitosan (Bordenave et al. 2007; Kuusipalo et al. 2005) or chitosan nanoparticles (Ma et al. 2010) in paper and paperboard, as a paper making additive or as a surface coating, has been previously investigated and showed that the well-known aptitude of chitosan to form strong thin films could be successfully applied to deposit them onto paper surfaces, thus improving the performance of the ensuing coated materials, in terms of final properties. The effects of chitosan molecular weight and degree of deacetylation on the improving physicochemical properties of gelatin-based films were studied (Liu et al. 2012). In the present work, bagasse paper sheets coating with water soluble gelatin and/or chitosan was reported. The mechanical properties, air permeability measurements and morphology of the ensuing materials were investigated, assessed and compared. Brought to you by | Tulane University Authenticated Download Date | 1/14/20 1:19 PM