May 6, 2020
PMHM. The Futurist Hybrid Material As A Solution To Car Accident Deaths
1869. The first death from a motor vehicle is recorded, the Irish scientist Mary Ward, in the remaining years of the same century, more similar cases begin to appear. 1909. Laminated glass is accidentally discovered and used to decrease deaths.
Both physical and psychological are the damages caused by a car accident, but they could be worse if it were not for the laminated glass, and the glass would not have the necessary characteristics if it were not for the resin that is inside it, ethyl vinyl acetate has been used, polyurethane resins, and even PVC derivatives. But our star resin is PVB. It works like ham inside a sandwich, the glass being the bread of the sandwich.
PVB (polyvinyl butyral) is an industrial polymer with great adherence, transparency and high durability, it is the key piece of laminated glass, those used in windshields.
Surely you have seen, in some movie or series, a car with a smashed windshield. Have you ever wondered why the different pieces of glass did not jump? It would be more dangerous if the small pieces jumped on top of the accident. Well, the PVB is the main responsible for this effect, they even work as acoustic insulators, thus preventing excess noise from entering the car’s interior and increasing the immersion effect of the driver. Its effect as acoustic insulation was compared to conventional glass in an S80® from the swedish company Volvo, using a class 8 tractor traveling side-by-side with the S80® as the sound source, laminated glass presented a loss of six decibels compared to conventional.
Thanks to its multifunctionality, brands such as Audi®, BMW®, Chrysler®, Mercedes® and Peugeot® make use of it.
However, in the last decade, it has been studied by researchers from the UANL of Mexico, since the material is a good candidate for polyfunctional & hybrid types, those that cover a large number of functions with their combination with the properties of another material.
The researchers managed to mix nanoparticles of metal oxides into the PVB. Thus making a hybrid material of the PMHM type. A Polymeric Magnetic Hybrid Material or PMHM is a combination, at the nanoscale, of a magnetic-inorganic component and a polymeric matrix. It is like a chocolate chip cookie, with the sparks being the nanoparticles of metallic oxides and the excess material being the PVB material. The main candidate applications of the hybrid material are as an actuator and as a sensor, since the material responds to external magnetic fields due to the properties of the nanoparticles. In themselves, PMHM-type materials have applications in micromanipulators, micropumps, biomedical devices, biomimetics, and more. El comportamiento del material resultó ser superparamagnético.
Superparamagnetism
Superparamagnetism is a property that certain materials have when their size is less than a critical size. In this case the nanoparticles of this materials was about five nanometers.
The hybrid material was able to change its mechanical properties by being in contact with a magnetic field. Possibly, in the not too distant future, this hybrid will be the replacement for the laminated glass used today. Possibly, in the future, the electronics of the cars is responsible for activating that magnetic field just at the moment of the crash, thus making the windshield malleable and behaving as a less rigid material, softening the blow of the passengers.
“The industrial importance, which could have this material, is based on the fact that a PMHM-film must be able to deform in a controlled way, when a magnetic field is applied.” — Dr. Reyes Melo et al. (UANL).
Resources:
- Reyes-Melo et al. Synthesis and characterization of a polymeric magnetic hybrid material composed of iron oxide nanoparticles and polyvinyl butyral. 2018
- López-Walle et al. Synthesis and mechanical characterization of magnetic hybrid materials with PVB as polymeric matrix for micro-actuation applications. 2014
- Puente Córdova et al. Materiales poliméricos dieléctricos. 2012
- Rentería-Baltiérrez et al. A fractional calculus approach to study mechanical relaxations on hybrid films of Fe2O3 nanoparticles and polyvinyl butyral. 2020
