European Polymer Journal (DOI: 10.1016/j.eurpolymj.2024.112928) recently published a study by the University of Lyon on polypropylene-based microfoam materials. The research compared new Li-ionomers with traditional Zn-ionomers in foam preparation and highlighted imidazolium ionic liquids (ImILs) from CHEMFISH TOKYO in building high-performance ion networks, paving the way for eco-friendly foam material industrialization.

I. Research Background: Technical Bottlenecks in Foam Material Preparation

Polypropylene (PP) foam, used in packaging, soundproofing, and insulation, faces two challenges in preparation:

• Low Melt Strength: PP struggles to maintain bubble structure in a molten state, leading to foam collapse.

• High Crystallinity: Conventional blowing agents like supercritical CO₂ are unevenly dispersed in semi-crystalline PP, hindering uniform micro pore structure formation.

Traditional solutions using Zn-ionomers for melt strength enhancement have drawbacks like complex processing and poor environmental adaptability. Ionic liquids (ILs), with customizable ions, are seen as key to overcoming these issues.

II. Key Innovation: ChemFish Ionic Liquids Enable New LIonomers

The research team combined maleic anhydride-grafted polypropylene (PPgMA) with CHEMFISH's ImILs to develop novel LIonomers:

• Reagent Selection:

  • E⁺DEP (1-ethyl-3-methylimidazolium diethyl phosphate): A non-reactive IL enhancing PPgMA melt viscosity via ion-dipole interactions.

  • AE⁺Br (1-aminoethyl-3-methylimidazolium bromide): A reactive IL with amino groups forming covalent bonds with PPgMA for stronger ion networks.

• Structural Characterization:

  • FTIR and NMR confirmed AE⁺Br's covalent cross-linking with PPgMA and E⁺DEP's dynamic physical cross-linking via ion pairs.

  • TEM showed LIonomers formed uniform ion-enriched phases (nanoscale cluster structures), unlike Zn-ionomers' distinct phase separation, highlighting ILs' advantages in multi-scale structural regulation.

III. Performance Breakthrough: LIonomers vs. Zn-Ionomer

1 Melt Strength and Foaming Efficiency

Significant advantages of LIonomers:

• LIonomers with 10 wt% AE⁺Br showed a 300% increase in melt viscosity over pure PPgMA, nearing Zn-Ionomer levels.

• In supercritical CO₂ foaming, LIonomers achieved a cell density of 10⁹ cells/cm³, five times that of Zn-Ionomers, with uniform cell size (average diameter < 50 μm).

Mechanism analysis:

• The dynamic cross-linked IL network effectively suppresses bubble coalescence and promotes uniform CO₂ dispersion during foaming. In contrast, Zn-Ionomers' rigid cross-links restrict bubble growth.

2 Mechanical Properties and Environmental Adaptability

Synergistic effects of LIonomers:

• LIonomers with E⁺DEP balanced stiffness (40% increase in elastic modulus) and tensile properties (60% increase in break elongation).

• LIonomers with AE⁺Br maintained foam structure stability at high temperatures (120°C), outperforming Zn-Ionomers in thermal stability.

IV. Core Value of ChemFish Products

• Reagent Customization Advantage:

CHEMFISH's ImILs boast high purity (>99%) and functional group adjustability (e.g., amino, phosphate groups) to meet diverse cross-linking needs. For instance, AE⁺Br's amino reactivity ensures covalent network formation, while E⁺DEP's non-reactivity suits dynamic ion bond building.

• Industrial Application Potential:

The study shows ChemFish ILs simplify LIomer preparation (no extra cross-linkers), cutting energy consumption by over 30% and offering an economical route for green foam material mass production.

V. Future Outlook

The team suggests LIonomers combined with ChemFish ILs could boost:

• Eco-Packaging: Replacing polystyrene foam to reduce white pollution.

• New Energy Materials: High-toughness foam substrates for battery separators.

• Smart Responsive Materials: Designing IL functional groups for temperature/pressure-responsive foams.

As a leading global Ionic liquid supplier, CHEMFISH provides high-performance chemicals for research and industry, with products used in polymers, catalysis, and new energy. This study further proves their key role in advanced polymer processing.