The effect of solvent mixture on the properties of solvent cast polylactic acid (PLA) film

Abstract

The objective of this study was to investigate the effects of various solvents on the crystallinity and thermal expansion stability of PLA film. Three different PLA films were produced by the solvent casting technique; PLA in chloroform (PLA-C), PLA in methylene chloride (PLA-M), and PLA in methylene chloride: acetonitrile ¼ 50: 50 (PLA-MA). The PLA-MA had higher % crystallinity, 46.15, than the PLA-C, 24.03, and the PLA-M, 14.25. With this increase in crystallinity, the PLA-MA had improved thermal expansion stability as shown by very low accumulated dimensional changes at 20 to 100 C. Wide-angle X-ray diffraction identified multiple crystalline structures for the PLA-MA. Film barrier properties were also measured. PLA-MA had the lowest oxygen permeability. However, there was no significant difference in water vapor permeability among the three PLA films. The mechanical property tests revealed that the PLA-C and PLA-M were ductile while the PLA-MA was brittle in behavior. The PLA-MA was very hazy as compared with the PLA-C and PLA-M. This work has shown that the PLA-MA had increased % crystallinity and, more importantly, it had improved thermal expansion stability which can be very beneficial for the flexible packaging industry.

Mechanical characterisation of polymer of intrinsic microporosity PIM-1 for hydrogen storage applications

“…The averaged complex and storage moduli was over 960 MPa with a standard deviation [18]. The influence of the solvent on polymer films' mechanical properties has been reported for such thermoplastics as PLA [34] and polystyrene [35]; therefore, this may also be the case for PIM-1. It is also necessary to consider the influence of polymer treatment on the results, as polymers are susceptible to processing history and every step, from polymer preparation in granular form to diluting it in different solvents, casting and drying in different conditions, may be significant to a final outcome.…”

Thermal transitions and solidification kinetics of poly(lactic acid) and blends with epoxidized natural rubber

“…It should be noted that a crystallization double peak for PLA has been observed during the heating cycle in experiments carried out by Liao et al [25] but no similar observations have been reported for crystallization from the melt state. In studies of the crystallization behaviour of PLA solvent-cast films Byun et al [26] have found that the formation of a single or double melting peak depends on the nature of the solvent, which determine whether mostly the PLA α-phase is formed or whether a mixture of α, β and γ crystals.…”

Oligomalonate Plasticized Poly(Lactic Acid) Films: Crystallization, Thermal, and Mechanical Properties

“…PLA films containing OTM presented practically no drastic variation of T m . Furthermore, T m values of the PLA films either non‐plasticized or plasticized by OTM are higher than those presented by PLA pellet, which is related to the fact that chloroform tends to increase the crystalline perfection due to its interaction with the polymer …”

“…However, PLA/OTM films presented three crystalline reflections at 17, 19, and 23° indicating that these films are semi‐crystalline materials. According to Byun et al these reflections are characteristics of PLA casting films from chloroform. It is interesting to note that the intensity of the reflection at 23° increases as OTM content increases from 1 to 5 wt%, but it is not significant when the content increases from 5 to 10 wt% OTM.…”