Supercritical Fluid Impregnation of Essential Bark Oil in Copolymers of L-Lactide with 7-Membered Cyclic Compounds

Tsutsumi, Chikara; Hara, Teruyuki; Ueno, Yuka; Nakayama, Yuushou; Shiono, Takeshi

doi:10.4236/jbnb.2014.53019

Cited by 5 publications

(12 citation statements)

References 34 publications

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“…The SSI was also reported for efficient loading of bark essential oil from Thujopsis dolabrata var. hondae and clove oil into poly(lactic acid) and polyethylene based films for food packaging, respectively [49,50].…”

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confidence: 99%

Supercritical CO2 impregnation of Gelatin-Chitosan films with clove essential oil and characterization thereof

Radović¹,

Adamović

Pavlović³

et al. 2019

CI&CEQ

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is the first study on supercritical impregnation of G/Ch films with clove oil (CO) • CO in films was affected by CO2 pressure, impregnation time and G:Ch ratio • CO loading was favoured at 10-20 MPa, impregnation time of 2-6 h and Gwt% 25-50% • ScCO 2 treatment had the highest plasticizing effect on G/Ch50:50 • Thermal stability of the G/Ch film with 56 mg CO/g film to 110 °C was demonstrated Abstract Supercritical CO 2 impregnation process was used for the first time to fabricate biodegradable gelatin-chitosan (G/Ch) films containing clove oil (CO) for potential use in active food packaging. All the impregnations were carried out at moderately low temperature (40 °C). Aiming to maximize CO loading in the films with acceptable morphological, structural and thermal properties, CO 2 pressure, impregnation time and G:Ch mass ratio were varied. Gelatin fraction in the films of 25-50 wt.%, scCO 2 pressures of 10-20 MPa and impregnation time of 2-6 h impregnation favoured the CO loading. Processing of the film with equal gelatin to chitosan mass ratio (G/Ch 50:50) at 10 MPa for 2 h yielded sufficiently high loading (56 mg CO/g film) without an adverse effect on morphological properties. The G/Ch 50:50 film was therefore chosen for structural and thermal analyses. ATR-FTIR analysis confirmed successful CO incorporation into the G/Ch 50:50 and its interaction with the film. Plasticizing effect of scCO 2 and CO on the film was evidenced by DSC. Incorporation of 56 mg CO/g film into the G/Ch 50:50 didn't affect thermal stability of the film. Beside environmental benefits, supercritical impregnation process enables fast fabrication of G/Ch bio-composite films containing CO, thermally stable to 110 °C, which is suitable for most of food packaging applications.

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confidence: 99%

Supercritical CO2 impregnation of Gelatin-Chitosan films with clove essential oil and characterization thereof

Radović¹,

Adamović

Pavlović³

et al. 2019

CI&CEQ

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“…The proportion of the copolymers obtained from the ACOP process was almost the same as that in the feed ratio similarly to conventional polymerization with monomer purification and gas replacement. In prior work, the T m and Δ H m values of copolymers of L‐LA with CL, TEMC and DXO were lowered remarkably as the L‐LA content was decreased, and the copolymers containing approximately 70% L‐LA had low degrees of crystallinity . A poly(L‐LA‐ ran ‐VL) specimen having an 85/15 composition had a T m of 153.2°C and a 28.9 J/g Δ H m value, while an 83/17 specimen synthesized by the ACOP method had values of 173.8°C and 35.4 J/g.…”

Section: Resultsmentioning

confidence: 95%

“…In prior work, essential bark oil has been incorporated into copolymers of L‐LA with CL, TEMC, or DXO at high concentrations using scCO 2 . During these trials, partial melting of the polymer surfaces was observed during processing with scCO 2 , even at low temperatures.…”

Section: Resultsmentioning

confidence: 99%

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Changes in the morphology of poly( l ‐lactide‐ ran ‐δ‐valerolactone) following supercritical carbon dioxide processing

Tsutsumi

Ishikawa

Takahashi

et al. 2019

Polymer Crystallization

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Biodegradable polymers can be employed as controlled‐release materials when processed with supercritical carbon dioxide (scCO2), and l‐lactide (L‐LA) random copolymers are useful in such applications. In the present work, poly(l‐lactide‐ran‐δ‐valerolactone) (poly(L‐LA‐ran‐VL)) copolymers, which do not melt during scCO2 processing above 80°C, were synthesized. The thermal properties, crystallinity, and polymer chain structures of these materials were evaluated before and after processing at temperatures from 60°C to 120°C and 14 MPa. An efficient one‐pot process (termed azeotropic‐combined one‐pot polymerization or ACOP) produced poly(L‐LA‐ran‐VL) or poly(L‐LA) in good yields and high molecular weights, and poly(L‐LA) with an Mn of 8.20 × 104 was obtained without the use of an inert gas. Poly(L‐LA‐ran‐VL) composed a 73/27 ratio of L‐LA and VL had a relatively high molecular weight despite its lower L‐LA content, and its Tm and ΔHm were decreased only slightly compared to that of poly(L‐LA). Both ΔHm and crystallinity were found to increase with increases in the scCO2 processing temperature, especially at 120°C. Although the degree of crystallinity increased with increasing L‐LA content, the ΔHm of the 83/17 specimen (which had the lowest Mn) was higher than that of the 91/9 sample. Before processing, the 73/27 copolymer had the highest haze value while the 91/9 specimen had the lowest, and there was a linear relationship between the haze and crystallinity of each copolymer after processing at all temperatures. The infrared spectrum of the 73/27 copolymer prior to scCO2 processing exhibited a maximum absorbance at 1756 cm−1, and this peak was shifted to higher wavenumber with increases in the processing temperature. Thus, infrared spectroscopy could be used to assess increases in crystallinity following scCO2 processing.

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“…Thus, scCO 2 can be used to combine these materials at low temperatures to produce composites based on the incorporation of oils in biodegradable polymers, with the aim of obtaining the spontaneous release of the oil vapors when required. To date, this technique has been applied to encapsulate oils in poly(L-lactide) [poly(L-LA)] or copolymers consisting of L-LA with other cyclic compounds 24–27 . Such technology could result in minimal environmental impact as well as lower energy usage and a reduction in labor.…”

Section: Introductionmentioning

confidence: 99%

Impregnation of poly(L-lactide-ran-δ-valerolactone) with essential bark oil using supercritical carbon dioxide

Tsutsumi

Manabe

Nakayama

et al. 2019

Sci Rep

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This work studied the incorporation of essential bark oil from Thujopsis dolabrata var. hondae, which is known to repel various insects, in poly(L-lactide-ran-δ-valerolactone) [poly(L-LA-ran-VL)] using supercritical carbon dioxide (scCO2). The poly(L-LA-ran-VL) was synthesized by first purifying the monomers by azeotropic distillation with benzene, followed by polymerization with Sn(oct)2 using the same equipment, representing an efficient one-pot process. The copolymerization of L-LA with VL using this technique at a feed ratio of 90/10 mol/mol gave poly(L-LA-ran-VL) (91/9) with a molecular weight of 6.48 × 104 g/mol and a high yield of 74.9%. Products with molecular weights over 5.0 × 104 g/mol were obtained at L-LA feed proportions of 70 to 90%. Impregnation trials were conducted between 40 and 120 °C at 14 MPa for 3 h. The oil content of a 73/27 specimen was found to increase significantly during processing at 100 or 120 °C. During enzymatic degradation with proteinase K, the 91/9 specimen showed the fastest degradation rate. Although the 71/29 sample was slowly hydrolyzed in a phosphate buffer at pH 7.0, the release of oil vapor from this material was slightly higher than that from the 91/9 specimen, and the vapor release rate continuously increased throughout the hydrolysis process.

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Supercritical Fluid Impregnation of Essential Bark Oil in Copolymers of L-Lactide with 7-Membered Cyclic Compounds

Cited by 5 publications

References 34 publications

Supercritical CO2 impregnation of Gelatin-Chitosan films with clove essential oil and characterization thereof

Supercritical CO2 impregnation of Gelatin-Chitosan films with clove essential oil and characterization thereof

Changes in the morphology of poly( l ‐lactide‐ ran ‐δ‐valerolactone) following supercritical carbon dioxide processing

Impregnation of poly(L-lactide-ran-δ-valerolactone) with essential bark oil using supercritical carbon dioxide

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