Performance Comparison of PP and HDPE, Two Commonly Used Raw Materials for Reagent Bottles

With the continuous expansion of the application scope of various polymer materials, plastic reagent bottles have gradually been more widely used in the storage of chemical reagents. Among the raw materials for the production of plastic reagent bottles, polypropylene (PP) and high-density polyethylene (HDPE) are two commonly used materials. So what is the difference in performance between these two materials?

1) Temperature Resistance

The embrittlement temperature of HDPE is -100°C and that of PP is 0°C. Therefore, when products require low-temperature storage, reagent bottles made of HDPE are more preferred, such as 2-8°C buffers used to store diagnostic reagents. Reagent bottles for Buffer and -20°C enzyme;

2) Chemical Resistance

Reagent bottles made of HDPE and PP are both acid and alkali resistant at room temperature, but HDPE is superior to PP in terms of oxidation resistance. Therefore, when storing oxidizing materials, HDPE reagent bottles should be selected;

Low molecular weight aliphatic hydrocarbons, aromatic hydrocarbons and chlorinated hydrocarbons can soften and swell polypropylene. Therefore, HDPE reagent bottles should be used when storing organic solvents such as benzene rings, n-hexane and chlorinated hydrocarbons.

3) Toughness and impact resistance

Polypropylene (PP) has excellent bending fatigue resistance, but poor impact resistance at low temperatures. The drop resistance of HDPE reagent bottles is much better than that of PP reagent bottles, so PP bottles are not suitable for low-temperature storage.

4) Transparency

PP is more transparent than HDPE and is more conducive to observing the status of the materials stored in the bottle. However, the particularly transparent PP bottles on the market currently have a transparent agent added to the material, so you need to pay attention when choosing a reagent bottle made of PP.

5) Sterilization method

In terms of sterilization methods, the only difference between HDPE and PP is that PP can be sterilized by high temperature and high pressure, but HDPE cannot. Both can be sterilized by EO and radiation (irradiation-resistant PP is required, otherwise it will turn yellow) and Disinfectants sterilize.