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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Bioproducts Research » Research » Publications at this Location » Publication #354018

Research Project: Bioproducts from Agricultural Feedstocks

Location: Bioproducts Research

Title: Recycled polyproplene-polyethylene torrefied almond shell biocomposites

item McCaffrey, Zachariah - Zach
item Torres, Lennard
item Flynn, Sean
item Cao, Trung
item Chiou, Bor-Sen
item Klamczynski, Artur
item Glenn, Gregory - Greg
item Orts, William

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/7/2018
Publication Date: 9/12/2019
Citation: McCaffrey, Z., Torres, L.F., Flynn, S.M., Cao, T.K., Chiou, B., Klamczynski, A.P., Glenn, G.M., Orts, W.J. 2019. Recycled polyproplene-polyethylene torrefied almond shell biocomposites. Industrial Crops and Products. 125:425-432.

Interpretive Summary: Torrefied almond shells as a plastic filler. Plastics often contain fillers and colorants and compatibilizers that are not renewable, may be costly, and generally do not improve the properties of the plastics. ARS researchers in Albany, CA have demonstrated that torrefied almond shells not only act as a natural pigment for plastics but also function as a renewable filler that can improve the properties of the plastics without the need of a compatibilizer. The results of these findings could extend the commercial value of almond shells and increase the renewable content of plastics.

Technical Abstract: The present study revealed that torrefied almond shells (TAS) can be used as a bioreinforcing agent for recycled polypropylene-polyethylene (PP-PE) blends without requiring a compatibilizer. Torrefaction of almond shells was performed to increase their hydrophobicity and provide good interfacial adhesion between matrix and filler. PP-PE samples blended with TAS were prepared using 3 different size ranges (sieved between mesh sizes of 100 and 120, 60 and 70, 35 and 45) and 7 different weight percent (%wt) loadings (0, 5, 10, 20, 30, 40, and 50). An increase in TAS loading resulted in an increase in flexural modulus, but a decrease in yield strength and toughness. The effect of particle size and %wt loading on the heat deflection temperature (HDT) and crystallinity of PP-PE biocomposites were analyzed by thermo-mechanical analysis (TMA) and differential scanning calorimetry (DSC), respectively. HDT increased with higher TAS loading and with smaller particle size. The maximum observed increase was 25 °C at 50 %wt loading of the small particles compared to neat PP-PE. The results for these biocomposites show that they can be potential candidates for consumer plastic applications.