Which of the following is not a semi-synthetic polymer ?

Options

A. cis-Polyisoprene
B. Cellulose nitrate
C. Cellulose acetate
D. Vulcanised rubber

Explanation

To determine which of the following options is not a semi-synthetic polymer, we need to analyze each option provided:

1. **Cis-polyisoprene**: This is a natural polymer derived from the polymerization of isoprene. It is commonly known as natural rubber and is not modified from a natural source, hence it is not classified as a semi-synthetic polymer.

2. **Cellulose nitrate**: This is a semi-synthetic polymer made by nitrating cellulose, which is derived from natural sources like cotton or wood pulp.

3. **Cellulose acetate**: This is also a semi-synthetic polymer produced by acetylating cellulose. Like cellulose nitrate, it is derived from natural cellulose.

4. **Vulcanized rubber**: This is a modified form of natural rubber (cis-polyisoprene) that has undergone a process called vulcanization, which enhances its properties. While it is derived from a natural source, the modification process classifies it as semi-synthetic.

Now, based on this analysis, we can conclude:

- **Cis-polyisoprene** is the only option that is not a semi-synthetic polymer. It is a natural polymer.

Therefore, the answer is **Option A: Cis-polyisoprene**.