How to distinguish whether the bristles of an industrial brush are made of PP or PA material

Brushes are widely used in our daily lives. There are various brushes in the market that cannot be answered. How do we determine whether industrial bristles are PP or PA?
Industrial brushes are literally easy to understand. The material is composed of "wool". The functions include "brushing", cleaning, polishing, polishing, sealing, dust prevention, filtering, and other functions. The most important part of a brush is the "hair". The general wool materials are animal hair, plant hair, plastic, metal wire, and abrasive wire. The cost of animal hair is high, while plant hair is prone to loss. Metal wire and abrasive wire are mainly used for industrial purposes. The most commonly used and relatively affordable price is plastic, including PA/PP/PBT/PE/PET. PBT/PE/PET is slightly toxic, PA/PP is non-toxic and is the preferred choice for customers, while PA/PP is the most suitable for PA.
1. PP, polypropylene is also a thermoplastic polymer that is acid and alkali resistant, but has poor flexibility compared to PA. It can also be made into hair of various diameters and colors, as acid and alkali can be used for medical purposes.
2. PA, nylon/nylon, is a thermoplastic polymer that is very wear-resistant, has strong elasticity, good flexibility, and good recovery after twisting. It can be made into wool of various diameters and colors.