A solvent-free processed low-temperature tolerant adhesive

Abstract

Ultra-low temperature resistant adhesive is highly desired yet scarce for material adhesion for the potential usage in Arctic/Antarctic or outer space exploration. Here we develop a solvent-free processed low-temperature tolerant adhesive with excellent adhesion strength and organic solvent stability, wide tolerable temperature range (i.e. -196 to 55 °C), long-lasting adhesion effect ( > 60 days, -196 °C) that exceeds the classic commercial hot melt adhesives. Furthermore, combine experimental results with theoretical calculations, the strong interaction energy between polyoxometalate and polymer is the main factor for the low-temperature tolerant adhesive, possessing enhanced cohesion strength, suppressed polymer crystallization and volumetric contraction. Notably, manufacturing at scale can be easily achieved by the facile scale-up solvent-free processing, showing much potential towards practical application in Arctic/Antarctic or planetary exploration.

Fig. 1. Schematic illustration of the low-temperature effect on adhesion behaviors.

a The lowest temperatures of the South Pole and representative outer space planets. b The schematic illustration of the low-temperature effect on adhesion behaviors for the solvent-assisted and solvent-free POMs-based adhesives.

Fig. 2. Characterization of the SSFP adhesive.

a FT-IR spectra of SSFP, SiW₁₂, and PEG. b PXRD patterns of SSFP, SiW₁₂, and PEG. c ³²Si NMR spectra of SSFP and SiW₁₂. d ¹H NMR spectra of SSFP and PEG. e ¹³C CP-MAS NMR spectra of SSFP and PEG. f ¹³C NMR spectra of SSFP and PEG. g Proton transverse relaxation curves of SSFP and PEG. h Crosslink densities of SSFP and PEG.

Fig. 3. Morphology and strength property of SSFP adhesive.

a SEM and corresponding elemental mapping images of SSFP adhesive. b Macroscopic photographs of SSFP adhesive obtained in kilogram scale and shear strength test. c Photograph of the weights bonded by SSFP adhesive. d Emergency leakage test performed using SSFP adhesive. e Adhesion strengths of SSFP adhesive on various substrates. f Adhesion strengths of SSFP adhesive on the interfacial adhesion system in various organic solvents for 14 days. The error bars for (e, f) represent mean ± standard deviation (n = 3 independent samples).

Fig. 4. The behaviors of solvent-free SSFP adhesive under a wide temperature range.

a The reversible curve of storage modulus (G′) and loss modulus (G″) of SSFP adhesive at cyclic temperature (T). b The reversible curve of complex viscosity (ƞ*) of SSFP adhesive at cyclic temperature (T). c Macroscopic adhesion tests of SSFP adhesive in liquid nitrogen. d Adhesion strengths of SSFP adhesive on SS substrate at various temperatures. e Rheology measurements of SSFP adhesive between −120 and 80 °C. f Temperature-dependent FT-IR spectra of SSFP adhesive from −196 to 65 °C. The error bars for (d) represent mean ± standard deviation (n = 3 independent samples).

Fig. 5. Theoretical calculation for the interaction between SiW₁₂ and PEG.

a Schematic illustration of the interaction between SiW₁₂ and PEG for the adhesive formation (one, two, and three PEG fragments from left to right, respectively). b Snapshots of the aggregation behavior of SiW₁₂ and PEG at 25 °C. c Snapshots of the aggregation behavior of SiW₁₂ and PEG at −196 °C. d The interaction energy of PEG and SiW₁₂ during simulated process at 25 °C and −196 °C.