The Effect of Titanium Dioxide Surface Modification on the Dispersion, Morphology, and Mechanical Properties of Recycled PP/PET/TiO2 PBNANOs

Eider Matxinandiarena; Agurtzane Múgica; Manuela Zubitur; Cristina Yus; Víctor Sebastián; Silvia Irusta; Alfonso David Loaeza; Orlando Santana; Maria Lluisa Maspoch; Cristian Puig; Alejandro J Müller

doi:10.3390/polym11101692

The Effect of Titanium Dioxide Surface Modification on the Dispersion, Morphology, and Mechanical Properties of Recycled PP/PET/TiO₂ PBNANOs

Polymers (Basel). 2019 Oct 16;11(10):1692. doi: 10.3390/polym11101692.

Authors

Affiliations

¹ POLYMAT and Polymer Science and Technology Department, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel de Lardizabal 3, 20018 Donostia-San Sebastián, Spain. eider.matxinandiarena@ehu.eus.
² POLYMAT and Polymer Science and Technology Department, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel de Lardizabal 3, 20018 Donostia-San Sebastián, Spain. agurtzane.mugica@ehu.eus.
³ Chemical and Environmental Engineering Department, Polytechnic School, University of the Basque Country UPV/EHU, 20018 Donostia-San Sebastián, Spain. manuela.zubitur@ehu.eus.
⁴ Department of Chemical and Environmental Engineering, Nanoscience Institute of Aragon University of Zaragoza and, Aragón Materials Science Institute, ICMA, CSIC, Pedro Cerbuna 12, 50009 Zaragoza, Spain. cyargon@gmail.com.
⁵ Department of Chemical and Environmental Engineering, Nanoscience Institute of Aragon University of Zaragoza and, Aragón Materials Science Institute, ICMA, CSIC, Pedro Cerbuna 12, 50009 Zaragoza, Spain. victorse@unizar.es.
⁶ Networking Research Center CIBER-BBN, 28029 Madrid, Spain. victorse@unizar.es.
⁷ Department of Chemical and Environmental Engineering, Nanoscience Institute of Aragon University of Zaragoza and, Aragón Materials Science Institute, ICMA, CSIC, Pedro Cerbuna 12, 50009 Zaragoza, Spain. sirusta@unizar.es.
⁸ Networking Research Center CIBER-BBN, 28029 Madrid, Spain. sirusta@unizar.es.
⁹ Centre Català del Plàstic (CCP), Universitat Politècnica de Catalunya Barcelona Tech (EEBE-UPC), C/Colom, 114, 08222 Terrassa, Spain. alfonso.david.loaeza@upc.edu.
¹⁰ Centre Català del Plàstic (CCP), Universitat Politècnica de Catalunya Barcelona Tech (EEBE-UPC), C/Colom, 114, 08222 Terrassa, Spain. orlando.santana@upc.edu.
¹¹ Centre Català del Plàstic (CCP), Universitat Politècnica de Catalunya Barcelona Tech (EEBE-UPC), C/Colom, 114, 08222 Terrassa, Spain. maria.lluisa.maspoch@upc.edu.
¹² Grupo de Polímeros USB, Departamento de Ciencias de los Materiales, Universidad Simón Bolívar, Apartado 89000, Caracas 1080A, Venezuela. cpuig@usb.ve.
¹³ POLYMAT and Polymer Science and Technology Department, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel de Lardizabal 3, 20018 Donostia-San Sebastián, Spain. alejandrojesus.muller@ehu.es.
¹⁴ IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain. alejandrojesus.muller@ehu.es.

Abstract

Titanium dioxide (TiO₂) nanoparticles have recently appeared in PET waste because of the introduction of opaque PET bottles. We prepare polymer blend nanocomposites (PBNANOs) by adding hydrophilic (hphi), hydrophobic (hpho), and hydrophobically modified (hphoM) titanium dioxide (TiO₂) nanoparticles to 80rPP/20rPET recycled blends. Contact angle measurements show that the degree of hydrophilicity of TiO₂ decreases in the order hphi > hpho > hphoM. A reduction of rPET droplet size occurs with the addition of TiO₂ nanoparticles. The hydrophilic/hydrophobic balance controls the nanoparticles location. Transmission electron microscopy (TEM_ shows that hphi TiO₂ preferentially locates inside the PET droplets and hpho at both the interface and PP matrix. HphoM also locates within the PP matrix and at the interface, but large loadings (12%) can completely cover the surfaces of the droplets forming a physical barrier that avoids coalescence, leading to the formation of smaller droplets. A good correlation is found between the crystallization rate of PET (determined by DSC) and nanoparticles location, where hphi TiO₂ induces the highest PET crystallization rate. PET lamellar morphology (revealed by TEM) is also dependent on particle location. The mechanical behavior improves in the elastic regime with TiO₂ addition, but the plastic deformation of the material is limited and strongly depends on the type of TiO₂ employed.

Keywords: PBNANO; blend; morphology; nanoparticles; titanium dioxide.

Abstract

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