A police shield which is also referred to as anti-riot shield is an important equipment which is commonly used by police or law enforcement officers. They protect the officers against stone pelting or brick batting. This enables the officers to control riots without getting injured. They are available in a wide range of sizes and shapes which brings about the variation in prices. A good police shield should be able to withstand high amount of impact while still enabling the officers to have a full view of their main target; the riot of crowd they are trying to control. Therefore, the choice materials still remains an important factor you need to consider.
The most common types of anti-riot police shield is the polycarbonate police shields. These items are manufactured from polycarbonates due to the wide range of benefits these materials have to offer. They can withstand the “hostile environments” where the shields are used. All these attributes are due to the unique atomic structure and bonds which makes up polycarbonates. Of course, other materials such as acrylic can be used however, the polycarbonates are more reliable than any other material.
Which features make the polycarbonate police shield popular?
When dealing with riots, the strength of the shield plays a significant role. Polycarbonates are some of the strongest plastics which can withstand high levels of impacts.
For a high impact strength resistance; these items are made of reinforced polycarbonate material. But, what makes the polycarbonates to be impact resistant?
The polycarbonate police shields are strong and less fragile. Various tests which have been conducted indicate that polycarbonate sheets are about 200 times stronger than the ordinary glass. The polycarbonates are manufactured through polymerization process. In this process, the reaction involves the use of Bisphenol A which has two aromatic rings. The aromatic rings some of the most common types of unsaturated hydrocarbon which are generally stable. The polycarbonate compounds have the following atoms alongside the aromatic compounds: hydrogen, oxygen and carbon. The bond which is created between the atoms and the aromatic compound is one of the main reasons why this compound is known for its high resistance property.
When they are used as anti-riot shield, they will be able to withstand very large impacts without breaking. Moreover, the high melting point which makes it temperature resistant is due to the strong intermolecular bonds. Generally, polycarbonates share a lot of characteristics with polymethyl methacrylate (PMMA) thou; polycarbonates are stronger than PMMA. It has a glass transition temperature of about 302°F. The molecules of polycarbonate materials do not rotate around the bonds which results in this high glass transition temperature which makes it to be a very versatile material.
This material is flexible as compared to other plastic materials in the same category such as acrylic. Normally, flexible materials do not break easily. This is quite evident when both when both acrylics and polycarbonates are subjected to the same amount of impact; acrylic materials will be the first to break. All these features have been some of the main reasons why polycarbonate police shield are commonly used based on their strength.
Ideally, it is nearly impossible to predict the nature of riots law enforcement officers may encounter in their day to day activities. There a number of advanced anti-riot shield which have been developed which are bullet resistant. The good thing about such shields is that they have the ability to “catch” the bullets and absorb their energy. This makes them harmless. This is the same technology which is being used in the construction of bullet resistant panels.
Did you know that a polycarbonate material is one of those materials which can undergo a series of plastic deformations without breaking? This is also a clear indication of both its flexibility and strength. A good number of thermoplastics tend to crack when they are subjected to several plastic deformation processes. For sure, there is no reason as to why a security officer should risk carrying a shield which has been manufactured from another material other than polycarbonates.
It will be ridiculous to use an opaque polycarbonate police shield. How will you see your opponent? The fact that polycarbonate materials can transmit over 90% of light make them a perfect choice for this application. This is not by chance but due to the unique chemical property of this compound. Polycarbonates have amorphous structure which is responsible for their transparency. The Bisphenol A group which is used during the polymerization process and forms an important constituent of polycarbonates; plays a significant role in the inability of this material to crystalize. The light transmittance property is due to the two aromatic rings since they prevent the long chain polymer from “folding” and crystallization. It is important to note that the crystallization process reduces the optical clarity of materials.
The weight of these shields play a significant role too. Polycarbonates’ light weight has been one of the main reasons why these materials are used to manufacture police shields. It will not be fair enough to walk around with a shield which too heavy to an extent that you will end up spending much of your energy on lifting the shield. As a matter of fact, controlling a rioting crowd involves a lot of running up and down which also requires a lot of energy. This basically makes it futile to walk around with a shield which is heavy. A weightless shield will make it easier to maneuver and protect yourself from stones being thrown from different angles. Weight is a design feature which is really crucial here.
Generally, the polycarbonate police shield feature the following key features: resistance to impact, weightless, optical clarity and durability.
This does not imply that these materials are 100% perfect. Polycarbonates are not scratch resistant. To improve their ability to resist scratches which may reduce visibility; additional coating or treatments must be used. In addition to this, these shields must be UV protection. This is for the reason that pure polycarbonate materials are very vulnerable to UV light and thus their color turn to yellow when they are exposed to UV light. The yellow color and scratches will reduce visibility immensely if the materials was not treated properly.
Apparently, polycarbonate materials are so far the only suitable materials which can be used to make anti-riot shields.