What is the difference between high density polythene and low density polythene?
Polythene whether high density or low density is a polymer of ethene, CH2=CH2. When ethene molecules polymerize they can do so in two different ways. In the first, the polymer is effectively an unbranched arrangement of CH2 groups: [-(CH2-CH2)n-], and since these large molecules have no side chains, the polymer chains can arrange themselves very closely together, making the most effective use of van der Waals forces. This is high density polythene (HDP), and because the solid is largely crystalline, owing to the regular alignment of chains, this polymer is both relatively strong and possesses a relatively high melting point. In a different manufacturing process, the polymerization process creates side chains along the polymer chains; this makes it more difficult for the chains to pack as efficiently or as closely together. This is low density polythene (LDP), and, not surprisingly, this form has a lower density, more amorphous areas within the structure, and has a lower melting point,
