For the chemical industry, we mostly just know it as a traditional heavy industry, which seems not very related to our daily lives. However, upon closer examination, it appears that the chemical industry is closely intertwined with our lives. Because of this close relationship, the most concerning issue must be whether it poses any harm to us. In this article, the author will discuss whether some common chemical products around us pose a threat to human health.

Discussion Topic One: Plastic Bags

Plastic bags are essential in daily life, widely used due to their low cost, lightweight, large capacity, and convenience for storage. However, because plastic bags have a very long degradation cycle and are difficult to handle, some countries have banned their use and production. When we go out shopping, whether at a supermarket, shopping street, or eating out, we generally use plastic bags to carry our purchases. However, due to the subsequent issue of "white pollution," the use of plastic bags has been restricted, but their usage is still significant today.

How much do you know about plastic bags?

Plastic bags can be divided into four types: high-density polyethylene bags, low-density polyethylene bags, polypropylene bags, and polyvinyl chloride bags. The plastic bags that can affect human health are those used for food, and not all types of plastic bags are suitable for food storage. Generally speaking, food plastic bags made from polyethylene are non-toxic, while polystyrene and polyvinyl chloride are toxic, and of course, plastic bags can also be toxic.

So how can we distinguish whether a plastic bag is toxic?

We usually identify them by looking, touching, and smelling. The film appears milky white and semi-transparent (especially noticeable when several layers are stacked), feels smooth to the touch, as if coated with a wax layer, makes a crisp sound when shaken, is flammable when exposed to fire, has a yellow flame, and produces a smell similar to burning candle wax.

Toxic plastic bags are generally colored because they are often recycled, so pigments are added. If no pigments are added, they are transparent, feel slightly sticky to the touch, make a dull sound when shaken, are not easily flammable, extinguish when removed from the flame, and have a green flame.

In summary: Safe food plastic bags are harmless, but as chemicals, if they are placed with hot food, substances from the plastic can merge with the food. Although they are non-toxic, long-term excessive intake can still harm the body, so it is best to avoid using plastic bags for food, especially hot food.

Discussion Topic Two: Paint and Water-Based Paint

As the traditional "golden September and silver October" peak season arrives, real estate sales are expected to heat up. When it comes to decorating new homes, paint is indispensable. Most people are aware that the smell of paint should not be inhaled for long periods. Recently, a type of water-based paint has emerged in the paint industry, which is currently the most environmentally friendly paint. So what is the difference between this paint and traditional oil-based paint? Is it really harmless?

A Brief Introduction to Water-Based Paint

Water-based paint, scientifically known as water-based coating, uses water as a diluent and does not contain organic solvents. It is free from benzene, toluene, xylene, formaldehyde, free TDI, and toxic heavy metals. It is non-toxic, has no irritating odor, is harmless to the human body, does not pollute the environment, and has a rich paint film. Water-based paint can generally be divided into three categories: one is water-based wood paint with acrylic as the main component, the second is water-based wood paint with a combination of acrylic and polyurethane as the main component, and the third is 100% polyurethane water-based paint.

Differences Between Water-Based Paint and Oil-Based Paint

For water-based paint, the diluent used is water, while oil-based paint cannot use water as a diluent because oil and water are not compatible, leading to stratification. This means that adding water as a diluent to oil-based paint will result in two dispersed phases. So what diluent is used for oil-based paint? It is, of course, a similar organic solvent, which illustrates the principle of compatibility of similar substances. The difference in diluents is the most essential distinction between water-based paint and oil-based paint.