**7.10 Moisture content and uptake**

Films that have been previously weighed are kept in a desiccator for 24 hours. When the weight of each film does not change anymore, the final weight is recorded. The following formula may be used to calculate the percentage of moisture content.

$$\text{96Moisture content} = \frac{\text{Initial weight of film} - \text{Final weight of film}}{\text{Initial weight of film}} \times 100 \tag{5}$$

The test is carried out by storing previously weighed film in desiccators at a certain temperature and relative humidity level. The film is removed after three days and reweighed to estimate the percentage of moisture absorption [66]. The following formula may be used to calculate the percentage of moisture uptake.

$$\text{W6Moisture uptake} = \frac{\text{Final weight of film} - \text{Initial weight of film}}{\text{Initial weight of film}} \times 100 \tag{6}$$
