Silane-modified high-yield lignocellulosic fibers as reinforcement of polylactic acid: Enhancement of interfacial adhesion for high-performance biocomposites
Giulia Herbst, Roberto Aguado, Quim Tarrés, Marcos L. Corazza, Luiz Pereira Ramos, Pere Mutjé, Marc Delgado‐Aguilar
Abstract
This study investigates the enhancement of PLA-based biocomposites using high-yield mechanical stone groundwood (SGW) pulp, with a focus on reinforcing fiber-matrix interactions through silane-coupling fiber modification. Different fractions of SGW (20 and 30 wt%) and (3-glycidyloxypropyl)trimethoxysilane (GPS) as a coupling agent (3, 5, 7, and 10 wt%) were incorporated into the PLA matrix. Thermo-mechanical properties including melt flow index, melt rheology, tensile strength, and Young’s modulus were evaluated, along with thermal degradation behavior via TGA and DSC. Non-modified and partially modified SGW fractions (20 and 30 wt%) improved PLA-SGW interface, resulting in increased tensile strength (14 % and 27 % respectively). Biocomposites with 30 wt% SGW modified with 5 and 7 wt% GPS exhibited the highest tensile strength improvement, along with the rest of the properties, attributed to GPS influence on melt flow index and processability. The obtained biocomposites showcased properties comparable to commodity polypropylene composites. • Tensile strength of PLA increased by 39.3 % with 30 wt% of 7 wt%-GPS modified SGW. • GPS leads to a well-bonded PLA/SGW systems with coupling factors close to 0.20. • GPS-coupled SGW-reinforced PLA biocomposites constitute an alternative to PP/GF composites. • Stronger interfaces were confirmed by micromechanical, thermal, and rheological properties.