Poly Limonene Research Articles

Thermo-pressed blend films of poly(lactic acid)/poly(butylene adipate-co-terephthalate) with polylimonene for sustainable active food packaging

Poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) blends provide sustainable packaging solutions renowned for their robustness and biodegradability. Herein, we used a commercial PLA/PBAT blend (Ecovio® - E) to develop films by thermo-pressing, incorporating polylimonene (PLM) and comparing them with limonene (LIM) at 5% and 10% additive concentrations. Remarkably, E/PLM10% film exhibited an 84.9% reduction in Staphylococcus aureus count and a 62% decrease in Aspergillus niger count, surpassing LIM and PLA/PBAT. Additionally, PLM substantially improved the antioxidant activity of the films, achieving more than 40% DPPH scavenging and providing light-blocking capability, with E/PLM5% virtually halting UV-A transmission. Mechanical assessments showed that, although higher PLM levels reduced tensile strength, E/PLM5% matched control performance. FT-IR analysis confirmed PLM presence without chemical alterations, and minimal changes in crystallinity were observed via DSC and XRD, while TGA confirmed the attractive thermal stability of the films. Expanding on these findings, we evaluated film efficacy in cherry tomato preservation, including unpackaged controls. E/PLM5%-packaged tomatoes exhibited superior visual quality and fungal inhibition, proving a promising option for active food packaging due to their antimicrobial effectiveness, antioxidant activity, and UV-light protection. Therefore, this study represents significant progress in advanced packaging development, providing prolonged food preservation, sustainability, and retained performance even when prepared in simulated industrial conditions.

Ultrasound Assisted Synthesis of Polylimonene and Organomodified-clay Nanocomposites: A Structural, Morphological and Thermal Properties

Polylimonene-clay nanocomposites (PLM-Mag 2, 3, 6 and 10% by weight of clay) were prepared by mixing Maghnite-CTA+ (Mag-CTA+) and polylimonene (PLM) in solution using ultrasonic irradiation. The catalyst preparation method were studied in order to determine and evaluate their structural, morphological and thermal properties. The Mag-CTA+ is an organophylic montmorillonite silicate clay prepared through a direct exchange process, using green natural clay of Maghnia (west of Algeria) called Maghnite. The Algerian clay was modified by ultrasonic-assisted method using cetyltrimethylammonuim bromide (CTAB) in which they used as green nano-reinforcing filler. Polylimonene was obtained by the polymerization of limonene, using Mag-H+ as a catalyst. The morphology of the obtained nanocomposites was studied by X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and infrared spectroscopy (FT-IR). Thermogravimetric analysis (TGA) shows that the nanocomposites have a high degradation temperature (200−250 °C) compared with the pure polylimonene (140 °C). The analyses confirmed the chemical modification of montmorillonite layers and their uniformly dispersion in the polylimonene matrix. Exfoliated structures were obtained for low amounts of clay (2 and 3% by weight), while intercalated structures and immiscible regions were detected for high amounts of clay (6 and 10% by weight). Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

A Green Synthesis of Polylimonene Using Maghnite-H+, an Exchanged Montmorillonite Clay, as Eco-Catalyst

A new green polymerization technique to synthesis polylimonene (PLM) is carried out in this work. This technique consists of using Maghnite-H+ as eco-catalyst to replace Friedel-Crafts catalysts which are toxics. Maghnite-H+ is a montmorillonite silicate sheet clay which is prepared through a simple exchange process. Polymerization experiments are performed in bulk and in solution using CH2Cl2 as solvent. Effect of reaction time, temperature and amount of catalyst is studied, in order to find the optimal reaction conditions. The polymerization in solution leads to the best yield (48.5%) at -5°C for a reaction time of 6 h but the bulk polymerization, that is performed at 25°C, remains preferred even if the yield is lower (40.3%) in order to respect the principles of a green chemistry which recommend syntheses under mild conditions, without solvents and at room temperature. The structure of the obtained polymer (PLM) is confirmed by FT-IR and Nuclear Magnetic Resonance of proton (1H-NMR). The glass transition temperature (Tg) of the polylimonene is defined using Differential Scanning Calorimetry (DSC) and is between 113°C and 116°C. The molecular weight of the obtained polymer is determined by Gel Permeation Chromatography (GPC) analysis and is about 1360 g/mol. Copyright © 2019 BCREC Group. All rights reserved

Identification of non-intentionally added substances in food packaging nano films by gas and liquid chromatography coupled to orbitrap mass spectrometry

The control of chemical migration from new functionalized food contact materials (FCMs) is a challenge for meeting food safety requirements. The non-intentionally added substances (NIAS) constitute a group of chemicals that are not applied, but may be introduced or formed during the production process of FCMs. This study describes a multi-analytical approach for the evaluation of unknown substances that migrate from FCMs. A case study is presented using a developed polymer consisting of a monolayer film with polylactic acid (PLA), polylimonene (PL) and zinc oxide nanoparticles (ZnO NPs). This approach incorporates the platforms of ICP-MS (inductively coupled plasma mass spectrometry), to determine whether there is transference of ZnO NPs used as antimicrobial agent and, the systems GC-MS and LC-MS (gas / liquid chromatography coupled to a quadrupole orbitrap mass spectrometer) for the characterization of the chemical structure of NIAS using the molecular mass and specific features of mass fragmentation. The screening of unknown compounds comprised retrospective analysis and data processing using both, a mass spectral library and databases, for GC and LC data, respectively. This approach has provided the tentative identification and quantification of seven NIAS, 3 by GC (Tripropylene glycol diacrylate, 10-Heneicosene and α-Tocopherol acetate) and 4 by LC (N,N-Diethyldodecanamide, N-[(9Z)-9-Octadecen-1-yl]acetamide, 1-Palmitoylglycerol and Glycerol stearate). This migration study was carried out according to the standard protocols established by EU regulation for FCMs.