Nicolet avatar 370

All chemicals and solvents were purchased from commercial sources and used without further purification, except for pyridine-2,5-dicarboxylic acid N-oxide (H₂pydco) which was synthesized according to a reported method.^{29 (link)} Melting points were determined using a Barnstead Electrothermal 9300 apparatus. The infrared spectra were recorded in the range of 4000 to 400 cm⁻¹ on a Thermo Nicolet/AVATAR 370 Fourier transform spectrophotometer using KBr pellets. Elemental analysis (CHN) was performed using a Thermo Finnigan Flash-1112 EA microanalyzer. Metal content was measured by the Spectro Arcos ICP-OES spectrometer model 76004555 using in the range of 130–770 nm for ICP spectra. Thermal gravimetric analysis (TGA) was carried out under an air atmosphere from ambient temperature up to 950 °C with a heating rate of 10 °C min⁻¹ on a Shimadzu TGA-50 instrument.

All reagents were purchased from Energy Chemical or Aladdin in analytical grade. DANP was prepared from the literature’s method^{28 (link)}. ¹H and ¹³C NMR spectra were recorded on Bruker AVANCE 400 nuclear magnetic resonance spectrometer. DMSO-d₆ was employed as a solvent and locking solvent. Infrared (IR) spectra were recorded on an FT-IR spectrometer (Thermo Nicolet AVATAR 370). Decomposition (onset) temperature were recorded on a differential scanning calorimeter (DSC, TA Instruments discovery DSC25) at a scan rate of 5 °C min⁻¹. Elemental analyses (C, H, N) were performed on a Vario Micro cube Elementar Analyzer. Impact and friction sensitivity measurements were made using a standard BAM Fallhammer and a BAM friction tester.

All reagents were purchased from Energy Chemical or Aladdin in analytical grade. ¹H and ¹³C NMR spectra were recorded on Bruker AVANCE 400 nuclear magnetic resonance spectrometer. DMSO-d₆ was employed as a solvent and locking solvent. Infrared (IR) spectra were recorded on an FT-IR spectrometer (Thermo Nicolet AVATAR 370). Decomposition (onset) temperature were recorded on a differential scanning calorimeter (DSC, TA Instruments discovery DSC25) at a scan rate of 10 °C min⁻¹. Elemental analyses (C, H, N) were performed on a Vario Micro cube Elementar Analyzer. Impact and friction sensitivity measurements were made using a standard BAM Fallhammer and a BAM friction tester.

Melamine was purchased from AKSci and was used as supplied. Melaminium nitroformate (MaNF) and 3,6,7-triamino-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazole (TATOT) was synthesized according to the literature^{5 (link),29 (link)}.¹H NMR and ¹³C NMR spectra were recorded on a 300 MHz (Bruker AVANCE 300) nuclear magnetic resonance spectrometer. Chemical shifts for ¹H NMR and ¹³C NMR spectra are given with respect to external (CH₃)₄Si (¹H and ¹³C). [D₆] DMSO was used as a locking solvent unless otherwise stated. IR spectra were recorded using KBr pellets with an FT-IR spectrometer (Thermo Nicolet AVATAR 370). The density was determined at room temperature by employing a Micromeritics AccuPyc II 1340 gas pycnometer. Decomposition temperature (onset) was recorded using dry nitrogen gas at a heating rate of 5 °C min⁻¹ and different rates (5, 10, 15, and 20 °C min⁻¹, respectively) on a differential scanning calorimeter (DSC, TA Instruments Q2000). Its thermo behavior was also recorded by a Thermogravimetric Analysis (TG, TAQ50). Elemental analyses (C, H, N) were performed with a Vario Micro cube Elementar Analyzer. Impact and friction sensitivity measurements were made using a standard BAM Fallhammer and a BAM friction tester.

The hydrogel swell ratio was analyzed as follows. The hydrogels were lyophilized until dry. To ensure the success of the reaction, HAMA and MA were characterized by Fourier transform infrared (FTIR) spectroscopy (Nicolet AVA TAR370, Thermo Scientific, Waltham, MA, USA). Dry weight (Wd) was measured. Dried hydrogel samples (n = 3) were immersed in 50 mL of PBS at 37°C and allowed to swell. Swollen hydrogel samples were weighed to determine swollen weight (Ws) at different time points. The swelling ratio (Q) was calculated by the following equation: Q = Ws/Wd.
To characterize the enzymatic degradation properties, we placed the HAMA hydrogel samples in 1.5-mL centrifuge tubes with 1 mL PBS containing 10 units of hyaluronidase at 37°C. At a pre-defined time (Supplementary Table S1), the hydrogels for each condition were removed, frozen, and lyophilized. Mass loss was determined as the ratio of the final weight to the original dry weight. All experiments were repeated 3 times.