The selection of impact modifiers
Choice of impact modifier
The selection of impact modifiers should pay attention to the following aspects:
1. The compatibility with PVC resin should be moderate. If the compatibility is too large, the two are completely mixed at the molecular level. The impact modifier may play the role of plasticizer, which is closely attached to the PVC molecules, causing impact The force acts directly on the PVC chain and cannot improve the impact resistance. On the other hand, if the compatibility between the two is too small, the uniform dispersion cannot be achieved, the adhesion to PVC is lost, and the impact force cannot be absorbed.
2. The glass transition temperature should be low, which can improve the impact resistance of PVC at low temperature.
3. The molecular weight should be high, and if necessary, it is best to lightly cross-link to improve the reinforcing effect.
4. It has no obvious influence on the performance and physical properties of PVC.
5. The weather resistance should be good, and the mold release expansion should be small.
6. Good processability for blending with PVC.
7, heat resistance (deformation resistance, thermal stability) is better.