Novel Random Copolymers of Poly(butylene 1,4-cyclohexane dicarboxylate) with Outstanding Barrier Properties for Green and Sustainable Packaging: Content and Length of Aliphatic Side Chains as Efficient Tools to Tailor the Material's Final Performance.

Giulia Guidotti,Michelina Soccio,Nadia Lotti,Valentina Siracusa,Andrea Munari,Massimo Gazzano

doi:10.3390/polym10080866

Abstract

The present paper describes the synthesis of novel bio-based poly(butylene 1,4-cyclohexane dicarboxylate)-containing random copolymers for sustainable and flexible packaging applications. On one side, the linear butylene moiety has been substituted by glycol subunits with alkyl pendant groups of different length. On the other side, copolymers with different cis/trans isomer ratio of cyclohexane rings have been synthesized. The prepared samples were subjected to molecular, thermal, diffractometric, and mechanical characterization. The barrier performances to O2, CO2, and N2 gases were also evaluated. The presence of side alkyl groups did not alter the thermal stability, whereas it significantly influences the formation of ordered phases that deeply affect the functional properties, mainly in terms of mechanical response and barrier performance. In particular, the final materials present higher flexibility and significantly improved barrier properties with respect to the homopolymer and most polymers widely employed for flexible packaging. The improvement due to copolymerization was more pronounced in the case of higher co-unit-containing copolymers and for the samples with cyclohexane rings in the trans conformation.

Highlights

Plastic production has grown significantly around the globe
The molecular characterization data of the polymers under investigation are reported in Table 2: all the samples were characterized by high and similar molecular weights, proving that no significant thermal degradation reactions occurred during polymerization
New highhigh molecular weight containing side aliphatic of different different were prepared successfully by a simple,process, solvent-free can for be of lengths werelengths successfully by prepared a simple, solvent-free whichprocess, can be which of interest interest for industry

Summary

Introduction

Plastic production has grown significantly around the globe. The increased production of plastic requires more fossil resources, which have to be exploited.The production of plastic reached 335 MT in 2016, with an increase of 3.9% compared to the previous year. Plastic production has grown significantly around the globe. The increased production of plastic requires more fossil resources, which have to be exploited. The production of plastic reached 335 MT in 2016, with an increase of 3.9% compared to the previous year. In Europe, plastic grows stably, with 39.9% of total 49.9 MT demand in 2016 coming from packaging applications [1]. Barrier films are indispensable for many different applications, ranging from electronic devices to food packaging.

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