How high pressure CO2 impacts PLA film properties

Abstract

Abstract. This work investigated the sorption and the diffusion properties of CO 2 under high pressure and the further modifications induced in Poly(lactic acid) (PLA) thin layers. Poly(ethylene terephtalate) (PET) was also considered for comparative purposes. Firstly, from thermodynamic equilibrium, the CO 2 sorption isotherm (two sorption-desorption cycles, up to 25 bar, at 25°C) gave strong evidence of a physisorption mechanism and of a hysteresis phenomenon. Infrared spectroscopy analysis confirmed that no chemical reaction occurred. Secondly, from the kinetics aspect, the CO 2 diffusion coefficient was found around 10 -13 m 2 ·s -1 and was slightly faster for sorption compared to desorption. Additionally, when CO 2 sorption occurred, the PLA structure and its functional properties were modified due to plasticization and swelling. CO 2 plasticization reduced the glass transition temperature of PLA and accelerated the physical ageing of the polymer. These results are therefore of significant importance in industrial processing and applications which involve close contact between CO 2 and PLA.

The application of the synergistic effect between the crystal structure of poly(lactic acid) (PLA) and the presence of ethylene vinyl acetate copolymer (EVA) to produce highly ductile PLA/EVA blends

“…PLA has high strength (* 60 to 65 MPa) and high modulus (* 2.5 to 3.0 GPa), which makes it suitable for applications like bottles, office utensils, cups and trays. By modifications like plasticizing or flame retarding, it can even be used as a film for food packaging [24], or in electronic and automotive applications [25]. Nevertheless, PLA also has two main drawbacks that highly limit its widespread application: its low heat deflection temperature (HDT) (* 50 to 55°C) and low impact strength (* 3 kJ m -2 notched Charpy impact strength) [6].…”

Stabilization of Electrospun Nanofiber Mats Used for Filters by 3D Printing

“…Next, Figure 6b shows FTIR measurements of PAN nanofiber mats on 3D printed PLA. Figure 6a gives an overview of typical peaks of PLA [51,52,53,54] (grey lines) and PAN [55] (red lines), respectively.…”

Assessment of poly(L‐lactide) as an environmentally benign CO2 capture and storage adsorbent

“…The sorbed quantity was rather high than the values reported in the literature for PLA films under similar pressure and temperature conditions. [45,47,52] In the same conditions (15 bar and room temperature (RT)), Rocca-Smith et al [49] reported, in fact, an adsorbed quantity of CO 2 equal to 4%, which is similar to the adsorption capacity of cPLA and pPLA, while it is half of that recorded for the fPLA sample. The highest absorption of fPLA can be attributed to the morphology and crystalline structure of the sample.…”

“…Up to now, the related literature is mainly focused on the effects of supercritical CO 2 on the PLA properties and so there is not enough available information related to the effects of CO 2 at conditions lower than its supercritical point. [49] Properties of PLA depend on its component isomers, processing temperature, annealing time, and molecular weight (Mw). [50] In particular, the PLA lactides are formed by the condensation of two molecules of lactic acid, so three types of lactides can be obtained: dd-lactide, ld-lactide Poly-Dlactide acid (PDLA) and ll-lactide poly l-lactic acid (PLLA).…”

“…[51] At this regard, several authors, using a quartz crystal microbalance, studied the influence of the thermal history of a polymer film in the gas sorption and concluded that the polymer film thermal history only has significant impact in gas sorption for pressures higher than 2 MPa. [52][53][54] At the same time, Rocca-Smith et al [49] studied the sorption and the diffusion properties of CO 2 at high pressure and the changes induced by physisoprtion on the PLA films. They proved a good CO 2 adsorption capacity of PLA film with a small hysteresis cycle and the modification inducted by CO 2 pressure on the PLA film.…”