Effect of Extrusion Screw Speed and Plasticizer Proportions on the Rheological, Thermal, Mechanical, Morphological and Superficial Properties of PLA

Abstract

One of the critical processing parameters—the speed of the extrusion process for plasticized poly (lactic acid) (PLA)—was investigated in the presence of acetyl tributyl citrate (ATBC) as plasticizer. The mixtures were obtained by varying the content of plasticizer (ATBC, 10–30% by weight), using a twin screw extruder as a processing medium for which a temperature profile with peak was established that ended at 160 °C, two mixing zones and different screw rotation speeds (60 and 150 rpm). To evaluate the thermo-mechanical properties of the blend and hydrophilicity, the miscibility of the plasticizing and PLA matrix, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), oscillatory rheological analysis, Dynamic Mechanical Analysis (DMA), mechanical analysis, as well as the contact angle were tested. The results derived from the oscillatory rheological analysis had a viscous behavior in the PLA samples with the presence of ATBC; the lower process speed promotes the transitions from viscous to elastic as well as higher values of loss modulus, storage modulus and complex viscosity, which means less loss of molecular weight and lower residual energy in the transition from the viscous state to the elastic state. The mechanical and thermal performance was optimized considering a greater capacity in the energy absorption and integration of the components.

Developments of biobased plasticizers for compostable polymers in the green packaging applications: A review

“…CAPs derivatives are widely used as eco‐friendly plasticizers in various applications including biodegradable polymers food additives 50 . For food contact films various types of commercial CAPs such as TEC, TBC, ATEC, and ATBC were used for compostable polymers including PLA, 62,66–75 PHAs, 31,68,76–81 cellulose acetate, 82–84 PCL, 85 PBS, 66 and starch 86–88 …”

“…However, the highest performance was recorded at plasticizers concentration of 30 wt%. Gálvez et al 71 reported a reduction in storage module and loss modulus in PLA as ATBC content increased. It can be concluded that at least 20 wt% of CAPs are needed to increase ductility and improve flowability of PLA.…”

Dispersion of Micro Fibrillated Cellulose (MFC) in Poly(lactic acid) (PLA) from Lab-Scale to Semi-Industrial Processing Using Biobased Plasticizers as Dispersing Aids

“…Nowadays, there is growing interest in biobased materials, especially for food packaging applications, to substitute the currently used petrochemical-based polymers. Among them, polylactic acid (PLA) has gained interest, because it can be synthesized from natural resources [3]. PLA can be used for single-use items that are used at room temperature, e.g., plastic utensils, cold-drink cups, thermoformed lunch boxes which are not reusable plasticware, plastic films, or, and rubber toughened for frozen applications [4,5].…”

Study of the Physical and Mechanical Properties of Thermoplastic Starch/Poly(Lactic Acid) Blends Modified with Acid Agents

“…The typical band of the asymmetric stretching of C-O in the ester group appeared at 1182 cm −1 , and in the TPS and PLA blends presented a greater intensity for samples containing oleic acid [29]. Ultimately, in the fingerprint region, two bands at 868 and 755 cm −1 were related to the C-C stretch vibration that corresponded to the amorphous and crystalline phase of PLA, respectively [21].…”

“…The range of plasticizers that contribute to this problem continues to expand. The aforementioned characteristics enable TPS and PLA to be considered as candidates for developing new biopolymers from this blend [21,22]. However, these components show low compatibility due to the hydrophilic nature of starch and the hydrophobic nature of PLA.…”