One of the most widely used thermoplastics on the planet, polythene is used in a wide range of products, including shampoo bottles, children’s toys, and shopping bags. Depending on its molecular structure, it is divided into a number of subcategories, each of which has unique characteristics that make it suitable for use in particular applications. The most popular polythene types used by LDPE granules traders are as follows:
Lower density polythene (LDPE)
This transparent or translucent plastic is transparent or translucent, flexible, chemically resistant, and waterproof. Grocery bags, plastic wrap and film, flexible packaging material, and injection moulded parts are just a few of the things that may be made with it.
High-density polythene (HDPE)
HDPE is stronger and more resilient than LDPE. It has remarkable chemical resistance and comes in a variety of transparent to opaque hues. HDPE is the material used to make toys, outdoor furniture and structures, kitchen appliances, and plumbing pipes.
Comparative LDPE and HDPE Properties
Given that they are made of the same polymerised ethylene molecules, LDPE and HDPE share a number of characteristics.
For instance, both materials share the following characteristics:
• The material is light.
• Tensile strength of 0.20 to 0.40 N/mm2 or higher
• High resilience to impact
• Resistance to chemicals, water vapour, and the elements
• Considerable recyclable content
• Affordable fabrication and production costs
When employed in injection moulding processes, both materials also show the following traits:
• Melt temperatures between 180 and 280 °C (355 to 535 degrees Fahrenheit)
• Rapid rates of infusion
• Drying of finished components is unnecessary.
LDPE and HDPE are suitable for similar applications due, among other reasons, to the similarities in the properties described above.
Both materials are widely used in a number of sectors, including the ones listed below:
• Packaging Electrical Automotive Hydraulics and pneumatics
• Piping systems and pipes
Comparison of LDPE and HDPE
While LDPE and HDPE have some similarities, they also differ in a number of ways due to their fundamentally different internal compositions. Both materials are made of polymer chains, which in LDPE are more branched while in HDPE are more crystalline. Every substance has different material qualities as a result of the variety in polymer organisation.
Physical traits that differ Compared to HDPE, it is more forgiving and easier to work with. It also has a better level of transparency and a lower melting point (115° C). It is more prone to break under stress than HDPE is.
In comparison to polythene, HDPE is stiffer, more resilient, and more chemically resistant. It is more heat resistant than LDPE because it has a higher melting point (135° C). Additionally, the material has more strength and opacity due to its higher crystalline structure.
Both LDPE and HDPE can be recycled, but throughout the recycling process, they must be separated from one another. While HDPE is ranked as recycling number two, LDPE is ranked as recycling number four. LDPE’s softer nature and propensity to become lodged in recycling equipment can make it harder to recycle, depending on the product. Recycling machinery makes HDPE shipping and processing easier.
Differences between Manufacturing Techniques
In order to facilitate polymerization—the process by which monomers are joined together to form polymer strands—ethylene gas, a monomer, is compressed in an autoclave or tube reactor to create LDPE.
By heating petroleum at extraordinarily high temperatures, HDPE is created. Ethylene gas is split into monomers during this process, and those monomers are then joined to form polymer chains.
Higher Quality Plastic Products
While LDPE and HDPE share a number of positive characteristics, including superior chemical resistance and low solubility, they also have important material characteristics that have a substantial impact on their applicability for particular applications. When it comes to moulding and shaping sturdier, longer-lasting goods, HDPE is a much more reliable option than LDPE.