Improved Mechanical, Thermal, and Hydrophobic Properties of PLA Modified with Alkoxysilanes by Reactive Extrusion Process

Abstract

An eco-friendly strategy for the modification of polylactic acid (PLA) surface properties, using a solvent-free process, is reported. Reactive extrusion (REX) allowed the formation of new covalent bonds between functional molecules and the PLA polymeric matrix, enhancing its mechanical properties and modifying surface hydrophobicity. To this end, the PLA backbone was modified using two alkoxysilanes, phenyltriethoxysilane and N-octyltriethoxysilane. The reactive extrusion process was carried out under mild conditions, using melting temperatures between 150 and 180 °C, 300 rpm as screw speed, and a feeding rate of 3 kg·h−1. To complete the study, flat tapes of neat and functionalized PLA were obtained through monofilament melt extrusion to quantify the enhancement of mechanical properties and hydrophobicity. The results verified that PLA modified with 3 wt% of N-octyltriethoxysilane improves mechanical and thermal properties, reaching Young’s modulus values of 4.8 GPa, and PLA hydrophobic behavior, with values of water contact angle shifting from 68.6° to 82.2°.

A Comparison Study of Fiber Diameter's Effect on Characteristic Features of Donepezil/Curcumin‐Loaded Polycaprolactone/Polylactic Acid Nanofibers

“…While the T m values of PCL were observed around 60 °C, the T g and T m values of PLA were found between 50—80 and 150—180 °C. [ 43,44 ] In PNF8, PNF12, and PNF15 samples, there were endothermic peaks at 61.8, 68.1, and 63.1 °C. These peaks can be caused by the overlapping of PCL's T m point and PLA's T g point.…”

Poly(lactic acid)/ poly(ε-caprolactone) blends: the effect of nanocalcium carbonate and glycidyl methacrylate on miscibility

“…To enhance interfacial adhesion between the phases and reduce interfacial tension, the use of suitable compatibilizers is appropriate. Compatibilizers are typically macromolecules, such as block copolymers, which manipulate interfacial properties 31,32 . These macromolecules help reduce droplet size of the dispersed minor phase, stabilizing the minor phase against coalescence during melt mixing, and ensuring strong interfacial adhesion between phases 33,34 .…”

Poly(lactic acid)/ poly(ε-caprolactone) blends: the effect of nanocalcium carbonate and glycidyl methacrylate on interfacial characteristics

“…To enhance interfacial adhesion between the phases and reduce interfacial tension, the use of suitable compatibilizers is appropriate. Compatibilizers are typically macromolecules, such as block copolymers, which manipulate interfacial properties (Standau et al, 2019;Torres et al, 2021).…”