Processing and characterization of poly(lactic acid) films plasticized with commercial adipates

Abstract

The high brittleness of Poly(lactic acid) is a major drawback for flexible food packaging applications. The aim of this work is to evaluate the potential use of commercial adipates as PLA plasticizers to obtain transparent films with enhanced mechanical properties. Processing conditions were optimized. The effect of plasticizers was characterized by a decrease on the glass transition temperature and an increase in PLA chains mobility, which induced crystallization on heating. Thermal stability was not significantly affected, and mechanical properties showed an increase in ductility with the plasticizer content. Oxygen transmission rate was also measured to evaluate the effect of the microstructures generated by the presence of these additives in PLA-based films. The monomeric adipate presented lack of homogeneity that makes films plasticized with this additive not useful for the intended application. Good compatibility was observed between polyadipates (up to 20 wt %) and the matrix, making them promising materials for biodegradable films manufacturing. V

Properties and medical applications of polylactic acid: A review

“…The ductility of PLA was improved by the addition 20% plasticizer, where the elongation of PLA increased by a factor of 8 as compared to pure PLA when the plasticizer was added. In other work [57], two commercial grades of polymeric adipates were used as plasticizers. A very good plasticization effect of these materials was reported.…”

“…In addition, PLA bot- Figure 11. Transparent film of PLA/polyadipates blend and related thermal and structural properties [57] tles used in food applications were molded by a blow molding process. In the first step of this process, the parison (pre-form part) was shaped using the injection molding process.…”

Synthesis and Characterization of Lactic Acid Oligomers: Evaluation of Performance as Poly(Lactic Acid) Plasticizers

“…Concerning food 65 contact materials, there are several requirements to be 66 satisfied by additives, such as being non-toxic substances, 67 showing good miscibility with the polymer, providing high 68 tensile strength, ductility, and suitable thermal properties. [10]o r 75 polyadipates [11,12], but their compatibility with PLA 76 is limited and the possibility of incorporation with no 77 phase separation is restricted to concentrations lower than 78 20 wt% limiting their potential properties in food pack-79 aging. In general, it has been accepted that amounts from 80 10 to 20 wt% of plasticizers are required to provide a 81 substantial reduction of the PLA glass transition tempera-82 ture (T g ) as well as to obtain adequate mechanical prop-83 erties for films manufacturing.…”

“…This blending procedure for plasti-196 cized PLA was previously optimized and reported else-197 where [11,12]. Blends were then processed into films 198 (14.0 9 14.0 cm 2 and 220 ± 5 lm thickness) by com-199 pression molding at 170°C in a Carver Inc.…”

Industrial vegetable oil by-products increase the ductility of polylactide

“…Furthermore, plasticizers such as citrate esters [27][28][29][30][31][32][33][34][35][36][37], polyethylene glycols [27,33,[38][39][40][41][42][43][44] or manifold other molecules [29,43,[45][46][47][48] can be used. Unfortunately, impact modifiers are often not biodegradable nor biobased and plasticizers are generally derived from fossil resources, degrading one important environmental advantage of employing PLA.…”