Reticulação e análise de COF em filmes de polietileno

Abstract

Flexible packaging reaches highlighted position in the market world of the food industries, providing several requirements to products, such as protection, containment, utility and communication. One of the important properties that flexible packaging needs to have in filling lines, is the friction coefficient (FC), since without proper FC, filling can be impaired, causing delays in the process, losses and disposal. In order to obtain an adequate FC, it is necessary to incorporate sliding additives that tend to migrate between the polymer chains. If the migration does not occur as expected, there may be too much increase or decrease in the sliding additive on the film surface and promoting instability in the machine, impacting downtime and loss of performance. In this context, this study aims to develop control tools of additives migration of flexible packaging; thus compositions with 0%, 0.5%, 1.0% and 1.5% of the crosslinking agent (CA) were produced in an industrial batch, in order to produce thermoplastic systems with crosslinked polymer chains. The films were characterized by Fourier Transform Infrared Spectrometry (FTIR) and Differential Scanning Calorimetry (DSC). FTIR analyzes showed the band at 870 cm-1

increased in intensity with the CA increase, suggesting a greater interaction of the aromatic ring present in the CA structure with PE. The mechanical properties displayed the crosslinked PEs (0.5%, 1.0% and 1.5% CA) showed higher elastic modulus and less strain at break. From non-isothermal melt crystallization analyzes, the crystallization rate increased with cooling rates and decreased with CA addition, while the degree of crystallinity was subtly affected during melting, crystallization of crosslinked PEs presented higher degree of crystallinity. FC analyzes showed the film with the lowest FC was 1.5% AR. The crosslinking showed greater molecular chain restriction, providing greater control of the desired additive amount migration to the film surface and in general, the results give evidence that this is the most suitable content for industrial applications.