A facile strategy for synthesizing isosorbide-based polyurethane structural adhesives and core-shell rubber

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Materials

Background:

• Polyurethane (PU) adhesives are widely used in structural applications.
• Developing sustainable, high-performance adhesives from biomass is a key research area.
• Isosorbide-based polyols offer a renewable alternative for PU synthesis.

Purpose of the Study:

• To synthesize and characterize a series of biomass-based polyurethane (Biomass-PU) structural adhesives.
• To investigate the effect of varying isosorbide-based polyol content on adhesive properties.
• To optimize the formulation for enhanced impact strength and thermal stability.

Main Methods:

• Synthesis of Biomass-PU using polypropylene glycol (PPG2000), isosorbide-based polyol (RPO300), isophorone diisocyanate (IPDI), and 4-tert-butylphenol (BP).
• Evaluation of three different PPG2000/RPO300 ratios (9/1, 7/3, 1/1).
• Characterization using FT-IR Spectroscopy, NCO% titration, TGA, DSC, and GPC.
• Synthesis of core-shell rubber (CSR) with a PU shell for toughening.

Main Results:

• The Biomass-PU with a 9/1 PPG2000/RPO300 ratio exhibited superior impact strength (up to 35 MPa) and thermal properties compared to other ratios.
• The optimal formulation demonstrated improved compatibility with core-shell rubber (CSR) tougheners.
• Novel CSRs with polyurethane shells were successfully synthesized to further enhance impact strength.

Conclusions:

• The optimal formulation of Biomass-PU structural adhesive was determined to be a 9/1 ratio of PPG2000/RPO300.
• Biomass-based polyols can be effectively utilized to create high-performance structural adhesives.
• The developed Biomass-PU adhesive shows promise for applications requiring high impact strength and good thermal stability.