Comparison of Internal Electron Donors
¤ Phthalates (DIBP, DBP, etc.) were the earliest widely used internal donors, but face regulatory restrictions (REACH, RoHS).
¤ Diethers (diether donors) represent a phthalate-free mainstream solution, especially in high MFR, fiber, and thin-wall PP.
They often do not need external donors, simplifying catalyst formulation.
¤BMMF (fluorene-based donors) are high-end, phthalate-free donors with superior thermal stability, increasingly replacing
traditional phthalates in high-performance PP (transparent, rigid, high-flow).
¤ Succinate and diol esters are new environmentally friendly donors, offering flexibility in copolymer PP and impact-resistant
materials. They are growing in Europe and in pilot projects worldwide.
| Donor Type | Example | Key Features | Need External Donor | Applications |
|---|---|---|---|---|
| Phthalates | Diisobutyl phthalate (DIBP) | Mature, high isotacticity, but REACH-restricted | ✅ Yes | General homo-/copolymer PP |
| Diethers | 2-isopropyl-2-(1-methylbutyl)-1,3-dimethoxypropane
Synonym : 3,3-Bis(methoxymethyl)-2,6-dimethylheptane ; 1,3-Dimethoxy-2-isopentyl-2-isopropylpropane; DONOR C2; IIDP ;CAS NO:129228-11-1 |
High isotacticity, strong H₂ response, phthalate-free | ❌ No | High MFR PP, fibers, injection |
| BMMF | 9,9-Bis(methoxymethyl)fluorene
Synonym :9,9-Bis(methoxymethyl)-9H-fluorene CAS NO:182121-12-6 |
High stability, transparent PP, non-phthalate | ❌ No | High-performance PP, thin-wall |
| Succinates | Diethyl succinate | Flexible tuning, eco-friendly | ⚠️ Optional | Copolymer, high-impact PP |
| Diol Esters | 1,3-Propanediol bis(benzoate) | Rheology control, eco-friendly | ❌ No | High-impact, high-flow PP |
