Why does hdpe have a higher density

The list of uses is huge remember: versatile and popular. If you flip over your bottle of laundry detergent, it probably has the number 2 imprinted, surrounded by a chasing arrow. The code was designed decades ago to help get plastics recycling off the ground although today community recycling programs are less likely to ask for plastics by the resin code number than in the past. Thanks to collective efforts tracking back to the s, when plastics recycling really started to grow, HDPE has become quite skilled at evading landfills.

Nearly all curbside recycling programs today in the U. Some of the more typical uses include:. Learn More: The density of plastic. Remember those cereal liners I mentioned?

Polyolefins include linear low density polyethylene, low density polyethylene, high density polyethylene, polypropylene copolymer, polypropylene, and polymethyl pentene. These are the only plastics that have a lower specific gravity than water. This means that they weigh less than water. These materials can become brittle from oxidation and are damaged by exposure to UV light.

When ethylene is polymerized the result is relatively straight polymer chains. From the main chain they can branch out. We get different kinds of Polyethylenes from the varying degree of branching in their molecular structure. Below are brief descriptions on how the polyethylenes differ from each other.

This causes the low density to have a less compact molecular structure which is what makes it less dense. It has a density of 0. Because it has shorter and more branches its chains are able slide against each other upon elongation without becoming entangled like LPDE which has long branching chains that would get caught on each other.

It is less notch sensitive then HDPE and has better stress cracking resistance. LDPE is produced by compressing monomer ethylene gas in an autoclave or tubular reactor to facilitate polymerization—i.

HDPE is created by heating petroleum to very high temperatures. This process releases the ethylene gas monomers, which then combine to form polymer chains. Although LDPE and HDPE share a number of useful characteristics, including high chemical resistance and low solubility, they also have distinct material properties that affect their usefulness in different applications.

For more than 50 years, OMICO has been a premier provider of high-quality blow molded plastic parts and components for industries ranging from automotive to toy manufacturing. We accommodate a variety of plastic materials in our molding operations, including HDPE. For more information on our blow molding products and services, contact us or request a quote today. Are you searching for the right blow molding manufacturer for your company?