A Plastic Cup cannot, of course, exist without plastic. The key to plastic is its molecular structure, which is fused together by covalent chemical bonds. And because of its elasticity property, it is ideal for the mass manufacturing of products like plastic cups.
Generally speaking, plastic responds to heat in two forms: thermoplastics and thermoset. The former is "weaker," as it is prone to melting in minutes when exposed to heat. The latter is a bit more resilient because it is more likely to maintain its shape when exposed to mild heat. Short of being completely scorched, thermoset plastic is going to remain in its original state.
There are generally four ways to mold plastic into a desired shape, say, extrusion, blow extrusion, injection molding and blow molding. For the manufacturing of plastic cups, the most effective method is injection molding, wherein hot plastic is injected into a mold and the shape is then mass produced for maximum output.
The versatility of a molecular component like plastic makes it extremely efficient for creating dishware products, such as knives, forks, plates, and cups. Now, instead of worrying about how much water one uses to clean dishes, the fear of waste can be centered on taking up too much landfill space. Double-edged sword aside, plastic cups are ideal for parties with too many guests to accommodate regular cups with.
Some manufacturers now use PP or PET material for their cups, giving it a translucent look that cannot be achieved with paper cups. This, however, can be an annoyance when at a wedding or other family function and attempts at masking the fact that one's cup is filled to the brim with rum or some other colorful liquor. Then again, people who have plastic cups at their weddings are probably not too judgmental.
Environmental activists and concerned citizens have long been considering the effects of disposable cups on our environment and our wallets. It is often necessary and convenient to use disposable cups. This changes the debate from reusable vs. disposable cups to Styrofoam vs. plastic cups.
Well, if price is your main concern, plastic is the less costly option. It is lighter, which makes manufacturing and shipping less expensive. Styrofoam is a little more expensive to purchase, but it does double as a hot and cold drink cup, so it may be more cost-effective in the end, depending on your intended use.
In fact, Styrofoam insulates much more effectively than plastic, which means your cold drinks can stay colder longer and your hot drinks can stay hotter. Plastic cups are not recommended for hot drinks, and they do not have the insulation properties of Styrofoam.
However, Styrofoam is not biodegradable and cannot be recycled, which means that Styrofoam cups contribute to landfill trash. Chemicals are also used in the production of Styrofoam, such as benzene, that environmentalists claim are harmful to the environment. However,though most plastic cups are not biodegradable either, many of them are recyclable, which does make them the more environmentally friendly option.