Use of Nutshells as Fillers in Polymer Composites

Abstract

Nutshells are agricultural waste products that can be procured at relatively low cost. In this work we examined the possibility of using these biodegradable materials as fillers in poly(lactic acid) and low density polyethylene. The nutshells were ground into powder, blended with the polymer, and then injection molded with final weight varying from 10 to 40 weight %. The mechanical and thermal properties of the composites were then studied. In general, the addition of fillers caused reductions in mechanical properties to varying extents, but thermal properties were only slightly affected. The use of maleic anhydride and peroxide with the fillers had a negative effect on poly(lactic acid) but a slightly positive effect on the stiffness of polyethylene. The results suggested that polymer-nutshell composites may be usable in applications where cost is a concern and where some reductions in mechanical properties are acceptable.

Utilization of renewable filler from lichen in low density polyethylene

“…Δ H m , Δ H m , represents melting enthalpy of the sample and melting enthalpy of 100% crystalline low density polyethylene (293 j g −1 ), respectively . W indicates the weight fraction of LDPE in the composites.…”

Investigation on Polylactide (PLA)/Poly(butylene adipate-co-terephthalate) (PBAT)/Bark Flour of Plane Tree (PF) Eco-Composites

“…Many semi-crystalline polymers show multiple melting peaks due to bimodal crystal distributions produced by annealing, reorganization and recrystallization, polymorphism and different molecular weight species [52]. This phenomenon is also found for neat PLA and PLA blends and composites in the literatures [3,7,8,9,18,23,25,27,31,33,38,39]. The WAXD spectra (Figure 7) indicate that only one crystalline modification was developed in the samples and the double melting peak seen in the DSC heating run may reflect the melting of crystalline regions of various sizes and perfection.…”

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

“…Some authors have reported that fillers added to thermoplastic matrices restrict the movement of the chains of the polymeric material (reducing ductility), thereby increasing the modulus of elasticity [7]. However, the biocomposites of the neat PLA mixed with organic fillers without coupling agents had shown a similar tendency in the mechanical parameters [13,14].…”

“…Hence, it is desirable to use fillers of a natural origin that do not affect the biodegradability of the PLA matrix. The incorporation of natural fillers to the PLA and other polymer matrices has been reported by some authors [3,5,[13][14][15][16][17]. Some aspects, such as cost reduction, along with an improvement in the physical, chemical, mechanical, and thermal properties, are motivating the development of the 2 International Journal of Polymer Science biocomposites in order to reduce the use of synthetic plastics obtained from the oil.…”

“…The automotive industry uses nutshells in powders in order to clean engines without scratching their surface, whereas the cosmetic industry uses them as exfoliating agents in face, body, and feet cleaners. Some authors have reported that nutshells can be used as filler in the biocomposites of various applications where a high dimensional stability is required [7,13]. Moreover, the pecan nutshell powder (PNSP) is a hydrophilic biofiller that contains cellulose, lignin, tannins, and hemicelluloses.…”