1) Dissolution Test:Take a specific amount of the polymer powder and dissolve it in five times its weight in water. After stirring thoroughly, let the mixture stand undisturbed for 5 minutes, then observe. In principle, the less insoluble residue that settles at the bottom, the higher the quality of the polymer powder.
2) Film Formation Test:Take a specific amount of the polymer powder and dissolve it in twice its weight in water. Stir until uniform, let it stand for 2 minutes, then stir again until uniform. Pour the resulting solution onto a clean, flat glass plate, and place the glass in a well-ventilated, shaded area. Once completely dry, peel off the resulting polymer film. A film with high transparency indicates high quality. Next, subject the film to moderate stretching; a film exhibiting good elasticity indicates high quality. Finally, cut the film into strips and immerse them in water; after 24 hours, observe the strips—a film that dissolves minimally in the water indicates high quality.
3) Ash Content Test:Take a specific amount of the polymer powder, weigh it, and place it into a metal container. Heat the container to approximately 500°C. After calcining at this high temperature, allow the sample to cool back down to room temperature, then weigh it again. A sample with a lower resulting weight indicates higher quality.
