Optimization of tensile strength of PLA/clay/rice husk composites using Box-Behnken design

Abstract

It is extremely important to save costs and time while enhancing accuracy in experimentation. However, no study has utilized response surface methodology (RSM) to obtain the effects of independent parameters on properties of PLA/clay/rice husk composites. This study focused on optimization of tensile strength of fiber-reinforced polylactic acid (PLA) composites. RSM using Box-Behnken design (BBD) was used to determine optimum blending parameters of the developed composites. Fiber-reinforced PLA composites were prepared using compression molding. Rice husk fiber and clay filler were used to enhance tensile properties of PLA. Five factors, namely, clay filler loading (1 − 5 wt.%), rice husk fiber loading (10 − 30 wt.%), alkali concentration (0 − 4 wt.%), rice husk variety (K85, K98), and alkali type (NaOH, Mg(OH)2) were varied with 68 individual experiments. Tensile tests were carried out according to ASTM D638 standards. ANOVA results revealed that the quadratic models best fit the tensile strength response, with filler loading and fiber loading factors as the most significant model terms. Interaction effects were more predominant than linear and quadratic effects. The developed models used to determine maximum tensile strengths of PLA/clay/rice husk composites were in close agreement with experimental findings (R2 values of 0.9635, 0.9624, 0.9789, and 0.9731 for NaOH-modified K85 rice husks, Mg(OH)2-modified K85 rice husks, NaOH-modified K98 rice husks, and Mg(OH)2-modified K98 rice husks respectively). Individual optimal conditions were used to predict maximum tensile strengths in each set of developed composites. The predicted tensile strengths were 32.09 MPa, 33.69 MPa, 32.47 MPa, and 32.75 MPa for PLA/clay composites loaded with NaOH-modified K85 rice husks, Mg(OH)2-modified K85 rice husks, NaOH-modified K98 rice husks, and Mg(OH)2-modified K98 rice husks, respectively, which were very close to the obtained experimental values of 31.73 MPa, 33.06 MPa, 32.02 MPa, and 31.86 MPa respectively.

Rice Husk with PLA: 3D Filament Making and Additive Manufacturing of Samples for Potential Structural Applications

“…Also, nanocomposites of PLA with untreated rice husk at 4 and 6% [ 50 ] were made by an electrospun process, and although strength is reported to be doubled with respect to the neat sample, the results are not clearly presented. Other authors showed that combining PLA with rice husk 10–30% and clay 1–5% can increase tensile strength up to 33 MPa, although compression molding was used [ 51 ].…”

Thermal decomposition features of micro-nano rice husk/polylactic acid blends for 3D printing

“…While although researchers have done a large number of studies on plant fiber filled PLA composites, there are few studies focus on the thermal decomposition characteristics of 3D printed MNRH/PLA composites. [24][25][26] Costa et al investigated the thermal stability of pinecone residue toughened with acrylonitrile-butadiene-styrene (ABS) for 3D printing pens, and evaluated the thermogravimetric analysis of ABS, FR, FT, FB, and their filament composites. Results demonstrate that the first process from room temperature to 130°C is attributed to water evaporation, while the second process is related to the degradation of hemicellulose, lignin, and cellulose.…”

Epoxy‐Modified Pyrophyllite as a Multifunctional Chain Extender for Poly(latic acid)

“…[19,20] It has been already reported that adding a small amount of inorganic layered silicate as a filler modifier into the PLA matrix can not only improve the crystallization rate of PLA and enhance the crystallization performance of PLA, but also can improve the crystallization rate of PLA. [21,22] Besides, fillers such as clays [23] can enhance the comprehensive properties of polylactic acid materials. However, fillers able to act as chain extenders have been rarely reported so far.…”