Polyvinyl Butyral Composites Research Articles

In-Plane Mechanical Characterization of a Kevlar® Composite

Polymer-based composites are widely used in the automotive, security, aeronautical and space industries, to mention a few. This is because of their good mechanical properties, which are similar to those of metals but with the attraction of being lightweight. Kevlar® is extensively used as a reinforcement in the security industry owing to its good ballistic properties. This investigation presents a mechanical characterization based on in-plane quasi-static tensile testing of Kevlar® 29/phenolic resin with a polyvinyl butyral composite using a universal testing system. The methodology developed for the preparation of the coupons is based on pressure, temperature and time. As a result of this work, elastic moduli (EL and ET), Poisson’s ratio (νLT), shear modulus (GLT) and strengths (XT, YT, S) were obtained. It is worth mentioning that there is scarce or no characterization of this material in the literature, and those studies that do characterize it do not present the coupons’ thermoforming conditions or the reasons for the coupons’ dimensions (width, length and thickness).

The 0-3 Lead Zirconate-Titanate (PZT)/Polyvinyl-Butyral (PVB) Composite for Tactile Sensing.

In this study, a 0-3 piezoelectric composite based on lead zirconate-titanate (PZT)/polyvinyl-butyral (PVB) was fabricated and characterized for its potential application in tactile sensing. The 0-3 composite was developed to incorporate the advantages of both ceramic and polymer. The paste of 0-3 PZT-PVB composite was printed using a conventional screen-printing technique on alumina and mylar substrates. The thickness of the prepared composite was approximately 80 μm. After printing the top electrode of the silver paste, 10 kV/mm of DC field was applied at 25 °C, 120 °C, and 150 °C for 10 min to align the electric dipoles in the composite. The piezoelectric charge coefficient of d33 and the piezoelectric voltage coefficient of g33 were improved by increasing the temperature of the poling process. The maximum values of d33 and g33 were 14.3 pC/N and 44.2 mV·m/N, respectively, at 150 °C. The sensor's sensitivity to the impact force was measured by a ball drop test. The sensors showed a linear behavior in the output voltage with increasing impact force. The sensitivity of the sensor on the alumina and mylar substrates was 1.368 V/N and 0.815 V/N, respectively. The rising time of the sensor to the finger touch was 43 ms on the alumina substrate and 35 ms on the mylar substrate. Consequently, the high sensitivity and fast response time of the sensor make the 0-3 PZT-PVB composite a good candidate for tactile sensors.

Design and synthesis of transparent and flexible nanofibrillated cellulose films to replace petroleum-based polymers

Nanofibrillated cellulose films have garnered attention due to their interesting proprieties such as transparency and high mechanical strength. However, they are brittle, very hydrophilic, which is decreasing their potential applications. We have successfully achieved a simple and effective chemical modification based on polymer grafting and through plasticizer additions to increase the performance of the films as well as to improve the compatibility within conventional polymer. A preliminary study shows the possibility of using this film as an interlayer in safety glazing and/or bulletproof glass with polyvinyl butyral (PVB). The modified NFC films displays high optical transmittance (93 %), increases tensile stretch and is more hydrophobic (83°). A higher flexibility was also achieved, as the film was greatly stretched and bended without cracking or breaking. The NFC / PVB composite has three times more elongation at break, 13 % more specific energy absorbed with a half-tensile stress compared to an interlayer of PVB.

Polyvinyl butyral composites containing halloysite nanotubes/reduced graphene oxide with high dielectric constant and low loss

Polymer-based composites with high dielectric constant and low loss are highly desirable due to their inherent advantages of easy processability, flexibility, and lightweight. Herein, a functional nanofillers, halloysite nanotubes (HNTs) decorated reduced graphene oxide (rGO) hybrid microstructures (HNTs@rGO) was successfully prepared via controllable electrostatic self-assembly and in-situ heat reduction method. These hybrid microstructures combine characteristics of natural 1D ceramic nanotubes with large aspect ratio and high electric conductivity of rGO micro-sheets, which provided ideal material collocation in the construction of microcapacitors. The HNTs not only effectively prevented direct contact between the rGO micro-sheets in the composites but also played an important role in forming dielectric interface within microcapacitors. Consequently, an HNTs@rGO/polyvinyl butyral (PVB) composites containing a very low content of 5 wt% rGO exhibited an ultra-high dielectric constant of 150 and an extremely low loss of 0.12 at 103 Hz. It is believed that the unique characteristics and facile fabrication process of HNTs@rGO/PVB composite make it a potentially excellent candidate for flexible polymer-based dielectric materials applied in the capacitor fields.

Synthesis of highly dispersible IZO and ITO nanocrystals for the fabrication of transparent nanocomposites in UV- and near IR-blocking

Indium-doped zinc oxide (IZO) nanocrystals were successfully synthesized via the alcohol-assisted pyrolysis of a mixture of indium stearate and zinc stearate, which were fabricated by the direct reaction between the metals and molten stearic acid at a temperature of 260–270 °C. The ~ 10 nm IZO nanocrystals could be dispersed homogeneously in non-polar solvents such as hexane or chloroform, forming an optically clear solution. Transparent IZO-ITO (indium tin oxide)/polyvinyl butyral (PVB) nanocomposite with 10% IZO and 2% ITO loading shows more than 75% visible light transmittance, 100% UV-blocking (below 380 nm), and 100% blocking of NIR from 1600 to 2500 nm. Equilibrium molecular dynamic simulation results clearly stated the stearic acid wrapped IZO nanocrystals in PVB matrix would hardly affect the solubility parameter of PVB composite, indicating their good compatibility and guaranteeing the high transparency of PVB-based composites. Our strategy paves the way to facile synthesize non-polar solvent soluble nanocrystals and fabricate transparent PVB-based functional nanocomposite.

Preparation and characterization of SrS : Eu2+0.02, Dy3+0.01/polyvinyl butyral composites

The SrS:Eu0.022+, Dy0.013+ phosphors modified with stearic acid (SA) were compounded with the polyvinyl butyral (PVB) matrix to improve its chemical stability and luminescence properties. The structure and luminescence properties of modified and unmodified SrS:Eu0.022+, Dy0.013+ and SrS:Eu0.022+, Dy0.013+/PVB composites were studied. The results of x-ray diffraction showed that the crystalline of the modified SrS:Eu0.022+, Dy0.013+ phosphors (SrS:Eu0.022+, Dy0.013+-SA) has almost no change compared with SrS:Eu0.022+, Dy0.013+ phosphors. The infrared spectra indicated that the SA molecules were anchored onto the surface of the phosphors and ─Sr─O─CO─ bonds were formed. Microstructure of the samples was characterized by scanning electron microscopy. The investigation of fluorescence spectra reflected that the emission peak position of SrS:Eu0.022+, Dy0.013+/PVB composites appeared at 611 nm with no migration, whereas the luminescence intensity increased. The results of water-resistant tests proved that SrS:Eu0.022+, Dy0.013+/PVB materials had better chemical stability than SrS:Eu0.022+, Dy0.013+ phosphors.