Bis-α,ω-bisacylphosphane oxides: simple access to crosslinked polymers with tunable properties.

Area of Science:

• Polymer Chemistry
• Materials Science
• Organic Synthesis

Background:

• Photoinitiators are crucial for photopolymerization.
• Existing photoinitiators have limitations in controlling polymer architecture.
• Bisacylphosphine oxides (BAPOs) are effective photoinitiators but lack tunable activation.

Purpose of the Study:

• To develop efficient synthesis of novel tetrafunctional photoinitiators.
• To investigate wavelength-selective activation of these photoinitiators.
• To explore their application in creating advanced polymer materials with controlled properties.

Main Methods:

• One-pot synthesis of bis-α,ω-bisacylphosphine oxides (Bis-BAPOs).
• Coupling of α,ω-dibromoalkanes with sodium bis(mesitoyl)-phosphide.
• Stepwise irradiation using different wavelengths (450 nm and 385 nm).
• Characterization using atomic force microscopy, contact-angle measurements, migration analyses, and photo-DSC.

Main Results:

• Successful synthesis of Bis-BAPOs with absorption similar to BAPO.
• Demonstrated pairwise, wavelength-selective activation enabling controlled polymer growth and branching.
• Preparation of diverse polymer materials (hydrophilic, lipophilic, amphiphilic).
• Observed distinct surface chemistries and controlled curing behavior based on initiator structure.

Conclusions:

• Bis-BAPOs offer tunable photoinitiation for controlled polymer synthesis.
• Initiator architecture significantly impacts interfacial properties and curing kinetics.
• Bis-BAPOs are promising components for advanced photopolymer materials.