Latently Curable Ultra-High Molecular Weight Polymers with Dimensional Stability

Latently curable polymer systems offer broad utility in applications from adhesives to lithography and structural composites. However, conventional thermoplastics suffer from poor shape retention during curing, which is typically performed above the glass transition temperature ( T g ). Here, we demonstrate that ultra-high molecular weight (UHMW) styrenic copolymers overcome this limitation by kinetically segregating the two fundamental operative processes: disentanglement and covalent cross-linking. The high number of chain entanglements in these UHMW materials provides them with excellent dimensional stability even at temperatures 150 °C above their T g . Installing a well-known latent cross-linker, 4-vinylbenzocyclobutene, and plasticizing dodecane pendants gives single-component, latently curable UHMW materials with tunable viscoelastic properties and monolithic shape retention. Rheological and thermal analyses reveal that UHMW prepolymers host long relaxation times on the macroscale that resist deformation over the curing time scale. Ultimately, shape-defined thermosets are produced from premolded thermoplastics because UHMW polymers do not significantly deform during curing. This work establishes an approach to shape-retaining, latently curable polymers that decouple processability from dimensional compromise during curing, which may provide opportunities for advanced manufacturing and high-resolution patterning technologies.