Question

what type of intermolecular force leads to high density polymer​

Answer 1

Answer:

High density polyethylene, often abbreviated to HDPE, is a polymer whose monomer is ethylene. It is a thermoplastic with a very high strength to density ratio. HDPE is a very versatile plastic that has a wide range of applications – from pipes to storage bottles. When compared to other plastics, the melting point of high density polyethylene is relatively high.

Structure

HDPE is a type of polyethylene, the most common plastic which accounts for over 34% of the global plastic market. It is a polymer made up of a huge number of repeating units (known as monomers), and its chemical formula can be generalized as (C2H4)n. The branching in high density polyethylene is of a relatively low degree (when compared to other categories of polyethylene). The general structure of HDPE is illustrated below.

Structure of High Density Polyethylene

High density polyethylene is a hydrocarbon polymer that can be prepared from ethylene via a catalytic process. Some common catalysts used here include Ziegler–Natta catalysts, chromium/silica catalysts (Phillips catalyst), and metallocene catalysts.

Generally, in the polymerization process, these catalysts form free radicals at the end of the growing polyethylene molecules. They also add new ethylene monomers at the end of the molecules thereby forming a long linear chain.

HDPE mostly features a low degree of branching where the linear molecules or the polymer chains are packed together tightly. The presence of a strong intermolecular force results in a dense, highly crystalline material. However, the true mechanism of the synthesis of high-density polyethylene is still a debated topic.