A polymer is a large molecule comprised of numerous smaller molecules. It is possible for these large molecules to be linear, moderately branched, or highly interconnected. In the latter case the structure progresses into a large three-dimensional complex. The small molecules that serve as the basic building blocks for these large molecules are known as monomers (See Figure 1.1). An example of the relationship between a monomer and polymer is the commercially important material polyvinylchloride, which is comprised of the monomer vinyl chloride. The repeat unit in the monomer generally corresponds to the monomer from which the polymer was made. As with any rule, there are exceptions. For example, polyvinylchloride is formally thought to be made up of vinyl alcohol (CH2CHOH) repeat units; but factually, there is no such monomer as vinyl alcohol. The suitable molecular unit exists in the tautomeric form, ethanal (CH3CHO). In order to make this polymer, it is required that polyvinyl ethanoate is firstly prepared from the monomer vinyl ethanoate, and then to hydrolyze the product to yield the polymeric alcohol.
The size of a polymer molecule can be determined in one of two ways: mass or by the number of repeat units within the molecule. This latter indicator of size is deemed the degree of polymerization. …show more content…
Linear low-density polyethylene provides the high polyethylene shrink film the stretch rate required for stretch film. The majority of polyethylene bundling shrink films are created with low-density polyethylene. This is because low-density polyethylene offers a low shrink temperature along exceptional clarity. One of the most recognizable uses for polyethylene bundling film is for wrapping water bottles and canned goods. This is because polyethylene bundling film is much thicker and provides more strength than polyolefin or PVC shrink