PVB/ATO Nanocomposites for Glass Coating Applications: Effects of Nanoparticles on the PVB Matrix

Abstract

Films made of poly(vinyl butyral) (PVB) and antimony-doped tin oxide (ATO) nanoparticles (NPs), both uncoated and surface-modified with an alkoxysilane, were prepared by solution casting at filler volume fractions ranging from 0.08% to 4.5%. The films were characterized by standard techniques including transmission electron microscopy, thermogravimetric analysis and differential scanning calorimetry (DSC). In the polymeric matrix, the primary NPs (diameter ~10 nm) aggregate exhibiting different morphologies depending on the presence of the surface coating. Coated ATO NPs form spherical particles (with a diameter of 300–500 nm), whereas more elongated fractal structures (with a thickness of ~250 nm and length of tens of micrometers) are formed by uncoated NPs. The fraction of the polymer interacting with the NPs is always negligible. In agreement with this finding, DSC data did not reveal any rigid interface and 1H time domain nuclear magnetic resonance (NMR) and fast field-cycling NMR did not show significant differences in polymer dynamics among the different samples. The ultraviolet-visible-near infrared (UV-Vis-NIR) transmittance of the films decreased compared to pure PVB, especially in the NIR range. The solar direct transmittance and the light transmittance were extracted from the spectra according to CEN EN 410/2011 in order to test the performance of our films as plastic layers in laminated glass for glazing.

Hybrid nanoparticles embedded polyvinyl butyral nanocomposites for improved mechanical, thermal and microwave absorption performance

“…This decrease may be due to the fact that the bonds between the polymer and the nanoreinforced source prevent the light from crossing. 3 Similar results of PVB-based nanocomposites for UV-vis curve was found also by Pizzanelli et al 59 In order to measure the radar absorption capabilities of the synthesized bare PVB and 1.0 wt.% Ag:Co nanocomposite film, a Vector Network Analyser (VNA) and double ridged horn antenna shown in Figure 8(b) were used. The 15 Â 20 cm copper plate mounted on the Styrofoam bed was located 1.3 m away from the antenna as a reference reflector.…”

Dynamics of poly(vinyl butyral) studied using dielectric spectroscopy and 1H NMR relaxometry

“…In eqn (8), the contribution of methyl protons to w 0 0 NMR can be neglected since, at the investigated temperatures, the rotation about the C 3 axis certainly occurs at frequencies much higher than those explored here (see the ESI †). The contribution of protons in ''slow'' segments, related to the occurrence of dynamic heterogeneity and revealed by us through FID analysis, 29 can be safely neglected given their much longer T 1 . Indeed, dynamic heterogeneity has been reported for amorphous polymers up to a few tens of degrees above T g .…”

“…No signal was detected for mobile water or ethanol in 1 H Free Induction Decay (FID) analyses of the PVB film. 29 On the other hand, no evidence of constrained ethanol was present in the 13 C Cross Polarization Magic Angle Spinning NMR spectra (see Fig. S1 in the ESI †).…”

Unravelling Main- and Side-Chain Motions in Polymers with NMR Spectroscopy and Relaxometry: The Case of Polyvinyl Butyral

“…In spite of the large number of technological applications, only a few studies were reported concerning the dynamics of PVB [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. Recently, PVB dynamics was investigated by some of us over broad frequency and temperature ranges by DS and 1 H field-cycling (FC) NMR relaxometry, focusing on a commercial sample [ 21 ].…”