Preparation of polypropylene/octadecane composite films and their use in the packaging of cherry tomatoes

Abstract

Polypropylene (PP)/octadecane (OD) composite films were prepared via twin-screw extrusion, and their chemical, morphological, thermal, and surface properties and oxygen and water vapor permeabilities were analyzed as functions of the OD content and temperature. OD was dispersed well in the PP matrix, and two phases (i.e., the PP and OD portions) were present in the PP/OD composite films. When the temperature was increased from 10 to 30 8C, both the oxygen transmittance rate and the water vapor transmittance rate of the PP/OD composite films increased sharply because of the influence of the OD content. These results were related to the temperature-dependent changes in the morphological structure, such as changes in the the tortuous paths and crystallinity in the composite films because of the addition of OD. In the storage test, the PP/OD (83:17) composite films continuously controlled the gas concentration of the headspace and protected against environmental factors; this reduced the enzymatic activity and led to higher quality cherry tomatoes compared to the case when the pure PP and MP33000 films were used. V C 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44087.

Effect of porous zeolite on temperature-dependent physical properties of polypropylene/octadecane (PP/OD) composite films

“…During the last several decades, many different groups have conducted research studies on the permeability of various penetrant molecules (such as O 2 and water vapors) in polymers [3][4][5]. Among the studied materials, polymers characterized by temperature-dependent gas and water vapor permeability properties such as poly(alkyl acrylate) [3,5], poly(N-isopropylacrylamide) [1], polyurethane [6,7], low-density polyethylene/paraffin wax (LDPE/PW) composite films [2], and polypropylene/octadecane (PP/OD) composite films [8] are becoming increasingly important in packaging applications for agricultural products and medical devices. The quality of agricultural products strongly depends on atmospheric composi-tions, which are affected by variations of respiration rates, transpiration during storage, and distribution environments [1,3,5].…”

“…Therefore, chemical and physical properties of the packaging materials should be adjusted to provide optimal gas permeability properties for practical applications in various fields. Phase change materials (PCMs) are materials that store and release heat energy during temperature-driven phase changes [2,8,[10][11][12]. Among various PCMs, PW is readily available and possess desirable characteristics such as large latent heat storage capacity, chemical inertness and stability, and non-toxicity [2,[10][11][12][13].…”

“…For these reasons, PW-based materials have been investigated for energy storage applications and thermal protection systems [10][11][12]. Various research groups have studied polymer/PCM composites because of their ability to maintain shape stability during usage [2,8,10,11]. The polymer matrix is able to arrange PCM species in a compact form and minimize PCM leakage from the polymer even after melting.…”

“…They found that the incorporated fillers apparently improved thermal stability, thermal conductivity, and mechanical properties of the manufactured polymer/PCM composites for thermal energy storage and thermal protection applications [10,11]. In our previous researches, polymer/PCM composite films such as LDPE/PW and PP/OD composites were fabricated for food packaging and medical device packaging and sterilization applications, and their temperature-dependent permeation properties were explored as functions of the PCM content and temperature [2,8]. The melting temperature of PW varies from 5.5 to 90°C depending on the number of C atoms (C14-C50) in the chain, which can possibly allow the development of composite films with optimal gas permeability values relying in different operational temperature ranges.…”

“…The melting temperature of PW varies from 5.5 to 90°C depending on the number of C atoms (C14-C50) in the chain, which can possibly allow the development of composite films with optimal gas permeability values relying in different operational temperature ranges. The studied composite films contained two different phases (the polymer and PCM ones), and the resulting transformation of the PCM species into a polymer matrix occurring near the PCM phase temperature can significantly affect the morphology of the entire polymer/PCM composite and effectively create passing channels for various penetrants in the polymer matrix [2,8]. However, it is difficult to uniformly disperse PCM molecules in a polymer matrix during extrusion due to different flowabilities of the polymer and PCM species originating from the corresponding difference in their molecular weights [2,8].…”