As an indispensable daily necessity in modern life, the transparency of plastic sports water bottles is not only an important indicator of product quality, but also one of the key factors to improve user experience. However, environmental factors have a significant and complex impact on the transparency of plastic sports water bottles, mainly in terms of light, temperature and humidity.

Light is the main environmental factor affecting the transparency of plastic sports water bottles. The ultraviolet rays in the sun have strong energy, which can destroy the chemical bonds in the plastic molecular chain and cause the aging of the material. Long-term direct sunlight will not only accelerate the fading of the color on the surface of the water bottle, but also form tiny cracks and gaps inside the material. These defects will scatter light and reduce transparency. In addition, some plastics may undergo photochemical reactions under ultraviolet light to generate colored compounds, which further affects transparency. Therefore, it is recommended that users place plastic sports water bottles in the shade when outdoors, or use protective measures such as sunshades to effectively reduce the damage of ultraviolet rays to the water bottles.

Temperature is also an important factor affecting the transparency of plastic sports water bottles. Plastic materials have the characteristics of thermal expansion and contraction. As the temperature rises, the distance between plastic molecules increases, and the movement of molecular chains intensifies, which may lead to changes in the internal microstructure of the material, such as changes in crystallinity or rearrangement of molecular chains. These changes will affect the propagation path of light, thereby reducing transparency. In addition, high temperature may also accelerate the aging process of plastics, causing cracks and discoloration on the surface of the material, further affecting transparency. Relatively speaking, in a low temperature environment, although plastic materials are not prone to thermal aging, they will become harder and more brittle. Low temperature may cause stress concentration inside the material, which will also affect transparency. Therefore, users should avoid exposing plastic sports water bottles to extreme temperature environments for a long time to maintain their good transparency.

The effect of humidity on the transparency of plastic sports water bottles is mainly reflected in the hygroscopicity and hydrolysis reaction of the material. Some plastic materials such as polycarbonate (PC) have certain hygroscopicity. When the ambient humidity is high, the material will absorb moisture in the air, resulting in an increase in the distance between molecular chains and a weakening of the interaction force between molecules, thereby affecting transparency. In addition, moisture may also act as a catalyst to accelerate the hydrolysis reaction of plastics, causing material degradation and the generation of colored substances, further reducing transparency. Therefore, when storing and using plastic sports water bottles in a humid environment, care should be taken to keep the environment dry to reduce the impact of humidity on the transparency of the water bottle.