Effects of Processing Conditions and Plasticizing-Reinforcing Modification on the Crystallization and Physical Properties of PLA Films

Abstract

The polylactic acid (PLA) resin Ingeo 4032D was selected as the research object. Epoxy soybean oil (ESO) and zeolite (3A molecular sieve) were used as plasticizer and reinforcing filler, respectively, for PLA blend modification. The mixture was granulated in an extruder and then blown to obtain films under different conditions to determine the optimum processing temperatures and screw rotation. Then, the thermal behaviour, crystallinity, optical transparency, micro phase structure and physical properties of the film were investigated. The results showed that with increasing zeolite content, the crystallization behaviour of PLA changed, and the haze of the film increased from 5% to 40% compared to the pure PLA film. Zeolite and ESO dispersed in the PLA matrix played a role in toughening and strengthening. The PLA/8 wt% zeolite/3 wt% ESO film had the highest longitudinal tensile strength at 77 MPa. The PLA/2 wt% zeolite/3 wt% ESO film had the highest longitudinal elongation at 13%. The physical properties depended heavily on the dispersion of zeolite and ESO in the matrix.

Production of Eco-Sustainable Materials: Compatibilizing Action in Poly (Lactic Acid)/High-Density Biopolyethylene Bioblends

“…where: ∆H m is the melting enthalpy of PLA and BioPE; ∆H cc is the cold crystallization enthalpy; ∆H o is equilibrium melting enthalpy, where 100% crystalline PLA is 93.7 J/g [29], and 100% crystalline BioPE is 290 J/g [30]; W is the matrix content.…”

Use of crosslinking agent to produce high‐performance PLA/EVA blends via reactive processing

“…Differential scanning calorimetry (DSC) analysis was performed on 5 g samples in a DSC‐Q20 (TA Instruments, New Castle, United States) in a temperature range of 25–200 °C, with second heating in a nitrogen atmosphere using a heating rate of 10°C/min and a gas flow rate of 50 ml/min. The degree of crystallinity (X c ) of the compounds was calculated according to Equation (2) [ 21 ] : where ∆ H m is the melting enthalpy of PLA and EVA, ∆ H 0 is the equilibrium melting enthalpy, which was 93.7 J/g for 100% crystalline PLA [ 22 ] and 287.30 J/g for 100% crystalline PE, [ 23 ] considering that only polyethylene sequences crystallize, and W is the matrix content.…”

“…where ΔH m is the melting enthalpy of PLA and EVA, ΔH 0 is the equilibrium melting enthalpy, which was 93.7 J/g for 100% crystalline PLA [22] and 287.30 J/g for 100% crystalline PE, [23] considering that only polyethylene sequences crystallize, and W is the matrix content. The melt fraction plots were acquired by integrating the DSC peaks using INTEGRAL software and Equations (3) and ( 4).…”

Blown film stability for low, medium, and high molecular weight polylactic acid and their tensile properties

“…The PLA inherent brittleness usually requires additives to effectively produce blown films with acceptable properties. Although some authors reported that virgin PLA can only be successfully applied for rigid films applications, 12,13 a great deal of work has been done to improve processability and applications by adding plasticizers, 3,14–18 chain extenders 17,19 and toughening agents, 15–17,20,21 leading to improved mechanical, barrier and optical properties. Nevertheless, some melt strength enhancers, such as multifunctional epoxies and di-isocyanates, have not been approved for food applications, even if they are added at concentrations that are in compliance with regulations on compostability.…”