Plastics are an array of various synthetic or semi-synthetic substances that utilise polymers as the basic ingredient. Their plasticity allows plastics to be extruded, molded or pressed into various solid objects of different shapes. Plastics are known to have many applications in daily life, including everything from Lycra fabrics on top of cars to polypropylene parts on boats and aeroplanes. The uses of plastics go far beyond the surface of the earth, as they can be used to make almost anything. Plastics are currently being used in so many industries that it’s difficult to name them all. Here are some examples:
From the incredibly long list of different plastics that have been developed over the years, it is clear that plastics play an incredibly important role in modern day society. With technology constantly advancing, it has allowed plastics to develop into stronger, more durable materials. This has allowed plastics to replace many metals in common use, including iron, copper and nickel. Additionally, plastics have completely changed the way we do many things around us, such as why plastic shoes are the most popular footwear in the world. The uses of plastics goes so far beyond this however.
Plastics are unique in that they contain three vital elements – alkaline, polar and non-polar. These four elements combine together to create the properties and physical properties that plastics are known for. Alkaline polymers and their derivatives, such as polyacrylate, are extremely common in modern day plastics because of their ability to withstand high temperatures. This means that alkaline plastics are used for all kinds of exterior coatings, such as window tinting and roofing products.
Another popular application of polymers is in the injection moulding industry. Plastics moudings can be made using a wide variety of polymers including, but not limited to polyacrylate, polyacrylic and polypropylene. injection moulding is an extremely useful process and although moudings from polyurethane are more commonly used, injection moulding polymers and their derivatives are proving to be invaluable as well.
Polymer moudings are frequently found in the home environment. Plastics can be found in a variety of everyday items, such as food packaging, shower curtains and even some fabrics. Plastics are also found in the construction industry, particularly in the construction of car parts and other mechanical products. Plastics are used in the manufacturing of glasses, caps and medicines. Polymers are even occasionally used in human body tissues. While all this is fantastic, it does raise questions about the nature of plastics, specifically their molecular weight.
A major problem with understanding the molecular weight of plastic is that it is extremely difficult to define. As discussed above, plastics can be made from a wide variety of polymer formulations. However, each of these formulations have their own individual properties, which often lead to them exhibiting distinctly different physical properties. For instance, while polyester is known to be a relatively flexible material, when used to make plastic bottles it will tend to form into an extremely rigid structure. At the same time, low density polyols such as PVC have very poor stretch-ability.
The properties of plastics often stem from the formulation of the plastics themselves. Some of the most common plastics have excellent mechanical properties, such as thermal shock, impact strength and flexibility. However, others, such as polyvinyl chloride (PVC), have poor mechanical properties, with low melting points and chemical reaction rates with water. PVC has no melting point, whilst polyvinyl chloride melts at lower temperatures and is therefore able to pass through sinks and pipes relatively easily.
The melting point of plastics can be increased by subjecting them to high temperature fluctuations. This process called thermoforming allows plastic to adopt different conformities. Plastic sheets that have undergone thermoforming are then stretched on a heated conveyor belt, before finally being placed in a cooling chamber to solidify. Plastics that solidify this way are called thermoset plastics. The process of forming plastics by thermoforming has been around since 1950, but is still used today to manufacture plastic bottles and polymers for a variety of purposes.