PDMS/TiO2 and PDMS/SiO2 Nanocomposites: Mechanical Properties’ Evaluation for Improved Insulating Coatings

• Published in: Nanomaterials (Basel, Switzerland) Vol. 13; no. 10; p. 1699
• Main Authors: Cordoba, Aldo, Rivera-Muñoz, Eric Mauricio, Velázquez-Castillo, Rodrigo, Esquivel, Karen
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 22-05-2023; MDPI
• Subjects: Adhesion; Adhesion tests; Alcohol; Chemical bonds; Chemical interactions; Coatings; Contact angle; Crosslinking; Diamond pyramid hardness; Dielectric properties; Elastomers; Electrostatic properties; Elongation; Embrittlement; Hardness; Hydrophobicity; Infrared spectroscopy; insulate materials; Mechanical properties; Mechanical tests; Metal oxides; Modulus of elasticity; Molecular structure; Nanocomposites; Nanoparticles; Particle size; Polydimethylsiloxane; Polymer coatings; Polymers; Raman spectroscopy; reinforcers; Silicon dioxide; Sol-gel processes; Solvents; Tensile strength; Titanium; Titanium dioxide; Transmission electron microscopy; X-ray diffraction; United States > US; Mexico
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano13101699

The use of nanoparticles (NPs) as reinforcements in polymeric coatings allows for direct interaction with the polymeric chains of the matrix, resulting in a synergistic process through physical (electrostatic forces) and chemical interactions (bond formation) for the improvement of the mechanical properties with relatively low weight concentrations of the NPs. In this investigation, different nanocomposite polymers were synthesized from the crosslinking reaction of the hydroxy-terminated polydimethylsiloxane elastomer. Different concentrations (0, 2, 4, 8, and 10 wt%) of TiO2 and SiO2 nanoparticles synthesized by the sol-gel method were added as reinforcing structures. The crystalline and morphological properties of the nanoparticles were determined through X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The molecular structure of coatings was through infrared spectroscopy (IR). The crosslinking, efficiency, hydrophobicity, and adhesion degree of the study groups were evaluated with gravimetric crosslinking tests, contact angle, and adhesion tests. It was observed that the crosslinking efficiency and surface adhesion properties of the different nanocomposites obtained were maintained. A slight increase in the contact angle was observed for the nanocomposites with 8 wt% compared to the polymer without reinforcements. The mechanical tests of indentation hardness and tensile strength following the ASTM E-384 and ISO 527 standards, respectively, were performed. As the nanoparticle concentration increased, a maximum increase of 157% in Vickers hardness, 71.4% in elastic modulus, and 80% in tensile strength was observed. However, the maximum elongation remained between 60 and 75%, ensuring that the composites did not become brittle.