**2. Classification of polymers**

Although there are several elements that can be molecules of synthetic organic polymers, the main elements are carbon (C), hydrogen (H), oxygen (O), and nitrogen (N).

According to the process of obtaining, the polymers may be classified in to the following types:


**•** Natural polymers obtained directly from the plant or animal kingdom, for example, cellulose, starch, protein, natural rubber, nucleic acid, chitin, lignin, among others.

Within this classification, the synthetic‐based polymers have induced the accumulation of plastic in our environment, pollution sources of atmospheric, visual, and also contamination of soil and marine environments [1].

Thus, natural polymers, also known as polymers, are in complete growth, although their properties limit their applications compared to conventional polymers, but nevertheless, the market for biodegradable polymers is growing every year [2, 3] mainly by increasing access limited to nonrenewable fossil resources has contributed toward finding renewable natural sources for chemical synthesis of polymers with similar properties those based on petroleum, but its main feature is its biodegradability.
