Abstract
Random copolymers of poly(propylene 1,4-cyclohexanedicarboxylate) containing different amounts of neopentyl glycol sub-unit were investigated from the gas barrier point of view at the standard temperature of analysis (23 °C) with respect to the three main gases used in food packaging field: N2, O2, and CO2. The effect of temperature was also evaluated, considering two temperatures close to the Tg sample (8 and 15 °C) and two above Tg (30 and 38 °C). Barrier performances were checked after food contact simulants and in different relative humidity (RH) environments obtained with two saturated saline solutions (Standard Atmosphere, 23 °C, 85% of RH, with saturated KCl solution; Tropical Climate, 38 °C, 90% RH, with saturated KNO3 solution). The results obtained were compared to those of untreated film, which was used as a reference. The relationships between the gas transmission rate, the diffusion coefficients, the solubility, and the copolymer composition were established. The results highlighted a correlation between barrier performance and copolymer composition and the applied treatment. In particular, copolymerization did not cause a worsening of the barrier properties, whereas the different treatments differently influenced the gas barrier behavior, depending on the chemical polymer structure. After treatment, Fourier transform infrared analysis confirmed the chemical stability of these copolymers. Films were transparent, with a light yellowish color, slightly more intense after all treatments.
Highlights
Plastic packaging, that used for food packaging, accounts for a large proportion of the total polymer production due to a combination of several favorable factors such as being lightweight, flexible, strong, stable, impermeable, and easy to sterilize
As the gas barrier behavior is fundamental in food packaging applications in order to select the best material for prolonging food shelf life, while maintaining the safety and quality of the packed food throughout the storage period, our research work focused on the study of such properties in different situations for PPCE and P(PCExNCEy) random copolymers
In the case of the oxygen and nitrogen gas tests, the GTRs of the copolymers are only slightly higher than that of the PPCE homopolymer. This result is analogous to the one we previously found by investigating Poly(L-lactic acid) (PLLA)-based triblock copolymers, containing poly(butylene/neopentyl glycol succinate) random copolymers as central soft block [32]
Summary
That used for food packaging, accounts for a large proportion of the total polymer production due to a combination of several favorable factors such as being lightweight, flexible, strong, stable, impermeable, and easy to sterilize. Poly(propylene 1,4-cyclohexanedicarboxylate) (PPCE) and its random copolymers containing different amounts of neopentyl glycol sub-units (P(PCExNCEy) have been synthesized and characterized from the molecular, thermal, structural, and mechanical points of view [12] These new polyesters represent a new class of bio-based and biodegradable ecofriendly materials with the potential for use in food packaging applications. As the gas barrier behavior is fundamental in food packaging applications in order to select the best material for prolonging food shelf life, while maintaining the safety and quality of the packed food throughout the storage period, our research work focused on the study of such properties in different situations for PPCE and P(PCExNCEy) random copolymers. The correlation between chemical polymer structure and barrier properties was determined to establish structure-property relationships, which are of fundamental importance for evaluating the suitability of a certain material for a specific application
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
