Controlled migration of antifog additives from LLDPE compatibilized with LLDPE grafted maleic anhydride Koranit Shlosman a,b , Ran Y. Suckeveriene a,c , Jasmine Rosen-Kligvasser a,b , Roza Tchoudakov a , Evgeni Zelikman d , Raphael Semiat a and Moshe Narkis a * This paper summarizes a study of controlled migration of an antifog (AF) additive; sorbitan monooleate (SMO), from linear low density polyethylene (LLDPE) films containing a compatibilizer, LLDPE grafted maleic anhydride (LLDPE-g-MA). LLDPE/LLDPE-g-MA/SMO blends were prepared by melt compounding. Bulk and surface properties of compression molded LLDPE films containing SMO and LLDPE-g-MA were characterized using Fourier transform infrared spectroscopy and contact angle measurements. Thermal properties were investigated using a thermal gravimetric analyzer. Diffusion coefficient (D) was calculated, and AF properties were characterized using a “hot fog” test. Compression molded films were characterized for their morphology using high-resolution scanning electron microscopy, and rheological properties were measured using a parallel-plate rotational rheometer. It was found that the LLDPE/LLDPE-g-MA/SMO systems are characterized by a slower SMO migration rate, a lower diffusion coefficient, and lower contact angle values compared with LLDPE/SMO blends. These results are well correlated with results of a hot fog test. Morphological studies revealed a very fine dispersion of SMO in the LLDPE films, when 3 phr LLDPE-g-MA was combined with 1 phr SMO. Thermal analysis results show that the incorporation of 3 phr LLDPE-g-MA and 1 phr SMO significantly increases the decomposition temperature of the blend at T > 400° C. At high shear rates, the LLDPE blends show that the AF and the compatibilizer have a lubrication effect on LLDPE. Copyright © 2014 John Wiley & Sons, Ltd. Keywords: LLDPE; antifog; compatibilization; controlled migration; FTIR INTRODUCTION Since first introduced in the late 1970’s, the market of linear low density polyethylene (LLDPE) has grown [1] and currently accounts for ~25% of all polyethylene demand. [2] When used as films for greenhouses or for food packaging, a fogging phenomenon can be observed on the LLDPE film surface, because of the PE low surface energy (30 dyn/cm). [3,4] The condensation of water vapor in an enclosed mass of air into discrete droplets occurs when the low surface energy LLDPE film cools below the water dew point. This accumulation of water droplets occurs when the contact angle is about 90°, known as the “fogging” phenomenon. The contact angle is the primary factor determining the behavior of a liquid on a solid and is defined as the point at which the liquid/vapor interface meets the solid surface. [5–8] Fogging reduces the efficiency of analytical and medical instruments and nuisances in applications of food packaging and agricultural films. [9] The optical properties of a fogged film are damaged and transparency reduces, while haze increases. In food packaging, the “see through” property is strongly affected, the esthetics of the package is damaged, and the quality of the food may decrease to the point where it can no longer be sold. [4,10,11] In agricultural films and greenhouses, the small fog droplets reduce light transmission and inhibit growth. Also, the water droplets can cause the “lens effect”, where sunlight is being focused, and harms the plants’ top leaves. One of the practiced solutions focuses on the addition of antifog agents to LLDPE, which increases its surface energy and thus reduces the contact angle between a water droplet and an LLDPE surface, thus forming a continuous and uniform transparent film of water. [12] Antifog additives are typically non-ionic surfactants classi- fied into two types: (i) external, where the AF is applied using spray or dip coating on the polymer surface, and (ii) internal, where the AF is incorporated into the polymer matrix during compounding. Glycerol esters, polyglycerolesters, sorbitan esters, and alcohol ethoxylates are commonly used as antifog additives. [13] Sorbitan monooleate (SMO), which is a food additive approved for food contact by FDA, [14] was used in this research as an antifog agent. SMO, a small polar amphiphilic, is incompatible * Correspondence to: Moshe Narkis, Department of Chemical Engineering, Technion—IIT, Haifa, Israel. E-mail: Narkis@tx.technion.ac.il a K. Shlosman, R. Y. Suckeveriene, J. Rosen-Kligvasser, R. Tchoudakov, R. Semiat, M. Narkis Department of Chemical Engineering, Technion—IIT, Haifa, Israel b K. Shlosman, J. Rosen-Kligvasser Interdepartmental program in Polymer Engineering, Technion—IIT, Haifa, Israel c R. Y. Suckeveriene Department of Water Industries Engineering, Kinneret College in the Jordan Valley, Zemach, Israel d E. Zelikman Alon Tavor Industrial Zone, Tosaf Compounds, Afula, Israel Research article Received: 15 June 2014, Accepted: 27 July 2014, Published online in Wiley Online Library: 5 September 2014 (wileyonlinelibrary.com) DOI: 10.1002/pat.3390 Polym. Adv. Technol. 2014, 25 1484–1491 Copyright © 2014 John Wiley & Sons, Ltd. 1484