Development of green composites based on polypropylene and corncob agricultural residue

Authors: RAMOS, RÓGERSON - Universidade Federal Da Paraiba (UFPB); SIQUEIRA, DANILO - Federal University Of Campina Grande; WELLEN, RENATE - Universidade Federal Da Paraiba (UFPB); LEITE, ITAMARA - Universidade Federal Da Paraiba (UFPB); Glenn, Gregory - Greg; MEDEIROS, ELITON - Universidade Federal Da Paraiba (UFPB)

Submitted to: Journal of Polymers and the Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/2019
Publication Date: 5/13/2019
Citation: Ramos, R.R., Siqueira, D.D., Wellen, R., Leite, I., Glenn, G.M., Medeiros, E. 2019. Development of green composites based on polypropylene and corncob agricultural residue. Journal of Polymers and the Environment. 27:1677-1685. https://doi.org/10.1007/s10924-019-01462-7.
DOI: https://doi.org/10.1007/s10924-019-01462-7

Interpretive Summary: Green Composites Containing Corn Cob. Plastics are a major source of landscape and marine pollution yet they are still used widely due to the lack of viable alternatives. One way to reduce the amount of plastic in everyday products is to blend it with renewable agricultural residue. Scientists from Brazil and ARS found that corncob residue could be successfully blended with polypropylene to make materials that had sufficient tensile strength for many applications and were heat stable. This research could result in wider use of green composites containing agricultural residue.

Technical Abstract: Green composites of polypropylene (PP) and corncob (CCB) agricultural residue with CCB content ranging from 5 to 30 wt% were compounded by melt extrusion and their properties investigated by density measurements, thermogravimetric analyses, differential scanning calorimetry, scanning electron microscopy (SEM) and tension, flexural and impact properties. Properties were dependent on CCB content. SEM micrographs showed that PP/CCB composites are composed of all layers of the corncob, but with a higher content of woody ring and pith. Composites with CCB up to 20 wt% presented particles evenly dispersed into PP matrix and density values ranging from 0.929 to 1.026 g/cm3. Thermal analyses showed that CCB is thermally stable up to 200 °C, ensuring that no degradation took place during processing, and PP/CCB composites are more crystalline than neat PP. Tensile strength and elongation at break of the composites decreased respectively from 30 to 20 MPa, and 22.7 to 3.7%, and the elastic modulus increased while the impact strength remained practically constant at 14 J/m for the filling contents tested. Elastic and flexural moduli increased respectively from 906 MPa to 1.1 GPa and from 1.26 to 1.81 GPa with corncob addition.