Mechanical and thermal properties of coconut shell powder filled polylactic acid biocomposites: effects of the filler content and silane coupling agent

Abstract

The effects of the filler content and the coupling agent 3-aminopropyltriethoxysilane (3-APE) on the mechanical properties, thermal properties, and morphologies of polylactic acid (PLA)/coconut shell powder (CSP) biocomposites were investigated. It was found that increasing the CSP content decreased the tensile strengths and elongations at break of the PLA/CSP biocomposites. However, incorporating CSP increased their modulus of elasticity. The tensile strengths and modulus of elasticity of the PLA/ CSP biocomposites were enhanced by the presence of 3-APE, which can be attributed to a stronger filler-matrix interaction. The thermal stabilities of the biocomposites increased with the filler content, and they were enhanced by 3-APE treatment. Meanwhile, the presence of CSP increased the glass transition temperatures (T g ) and crystallinities (X c ) of the PLA/CSP biocomposites at a filler content of 30 php. After 3-APE treatment, T g and X c of the PLA/ CSP biocomposites increased due to enhanced interfacial bonding. The presence of a peak crystallization temperature (T c ) for the PLA/CSP biocomposites indicated that the CSP has a nucleating effect. The melting temperatures (T m ) and the T c values of the biocomposites were not significantly affected by the filler content and 3-APE. PLA/CSP biocomposites that had been treated with 3-APE presented the strongest filler-matrix interaction, as confirmed by SEM.

Characterization of Extruded Poly(lactic acid)/Pecan Nutshell Biocomposites

“…Moreover, another factor responsible for the decrease in strength is related to the differences in polar properties between the nonpolar PLA and the polar filler. The decrease in the maximum stress values in tension agrees with the results from other authors [4,27,29]. The elongation at break of the PLA-PNSP biocomposites is shown in Table 2.…”

“…The decrease in the elongation at break is expected considering that the addition of PNSP reduces the chain mobility of the PLA matrix and increases the stiffness of the biocomposite. A similar behavior has been observed on the elongation at break in thermoplastic biocomposites [4,7,14,22]. The tensile modulus values of the PLA-PNSP biocomposites are shown in Table 2.…”

“…Several studies have reported the use of biomass wastes as natural fillers in polymeric composites [1][2][3]. These composite materials are reinforced with natural fillers and fibers, such as peanuts shells, nuts, rice, coconut, and wood [4][5][6] and have low costs and density, good thermal insulation, strength, acceptable resistance, and abundant availability in certain regions [7,8].…”

Chemical Modification of Palm Kernel Shell Filled Polylactic Acid Biocomposite Films

“…Some of the techniques that improve fibre-matrix adhesion include fiber bleaching, acetylation, esterification, grafting of monomers, and the use of bi-functional molecules (Belgacem and Gandini 2004). Chemical modifications improve the mechanical properties, filler dispersion, and thermal properties of composites (Chun et al 2012(Chun et al , 2013aMohamad Rasidi et. al 2014).…”

Grafting telinne monspessulana fiber with vinyl-trimethoxysilane. Effect of dicumyl peroxide catalyst

“…During the third stage physical adsorption occurs of the reactive silanols through the hydroxyl groups of fiber via the formation of hydrogen bonds. The final stage consists of the actual formation of the silanol graft with the natural fiber, once the solvent had been eliminated and with increased temperature the formation of the -Si-O-C-bond takes place with release of water [4] [8]. (Figure 1).…”