Abstract:
Crosslinking has demonstrated significant effectiveness in synthesizing polymeric nanocomposite materials due to its capacity to form robust polymeric networks. However, because of their toxicity and carcinogenic properties, the conventional crosslinking agents used in these materials affects human health and the environment. To address this concern and promote eco-friendly alternatives, we explored sustainable and biofriendly materials for crosslinking. In this study, we used 3-methacryloxypropyltrimethoxysilane (MPTS) to modify the surface of nanocrystalline cellulose (NCC), starch nanoparticles (SNP), and nanoclay (NC), designing three types of biofriendly crosslinkers. We confirmed the successful coupling of MPTS with NCC, SNP, and NC through rigorous analysis using FTIR and 1H NMR spectra. These biofriendly crosslinkers were then employed to prepare hydrogels using N-isopropyl acrylamide (NIPA) as the model monomer. The resultant nanocomposite hydrogels demonstrated outstanding mechanical, thermal, and swelling properties. Compared to traditional crosslinker-based hydrogels, the synthesized nanocomposite hydrogels demonstrated good flexibility, high elongation, and excellent tensile and compressive strength. On the other hand, the mechanical properties of the conventional bi-functional N, Nʹ -methylene bis(acrylamide) (MBA) crosslinker were poor. Tensile deformation revealed that a traditional bi-functional MBA crosslinker-based hydrogel has poor mechanical characteristics. It demonstrated a tensile strength of 18 kPa, toughness of 10 kJ/m3, elongation at break of 200%, and Young's modulus of 3 kPa in the case of the 2 M hydrogel. However, the nanocomposite hydrogel with M-NCC as the crosslinker have a Young's modulus of 10 kPa, a tensile strength of 35 kPa, a toughness of 660 kJ/m3, and an elongation at break of 3300%. These findings show that the M-NCC based nanocomposite hydrogel outperforms the traditional crosslinker-based hydrogel in terms of mechanical performance. Additionally, the nanocomposite hydrogels demonstrated better thermal and temperature-responsive swelling properties. M-NCC, M-SNP, and M-NC as crosslinkers in the 3 M nanocomposite hydrogel preparation are responsible for this enhanced performance. With a tensile strength of 18 kPa, the NIPA(3)/M-NCC nanocomposite hydrogel outperformed the standard NIPA(3)/BIS hydrogel, which had a tensile strength of 6 kPa, among the other hydrogel formulations. In addition, the NIPA(3)/M-NCC nanocomposite hydrogel's toughness was significantly enhanced, measuring 162 kJ/m3 as opposed to the regular hydrogel's 5 kJ/m3. In addition, the NIPA(3)/M-SNP nanocomposite hydrogel and NIPA(3)/M-NC nanocomposite hydrogel displayed higher tensile strengths (7.2 kPa and 5.5 kPa, respectively) compared to the conventional hydrogel. Similarly, these nanocomposite hydrogels exhibited superior toughness values of 65 kJ/m3 and 44 kJ/m3, respectively. The nanocomposite hydrogels' elongation at break was also significantly increased. The NIPA(3)/M-NCC nanocomposite hydrogel exhibited an elongation at break of 1300%, while the NIPA(3)/M-SNP and NIPA(3)/M-NC nanocomposite hydrogels exhibited elongations at break of 1125% and 1100%, respectively. In contrast, the conventional hydrogel had an elongation at break of 150%. Similarly, the nanocomposite hydrogels' Young's modulus values were higher than those of the traditional hydrogel. The NIPA(3)/M-NCC nanocomposite hydrogel, NIPA(3)/M-SNP nanocomposite hydrogel, and NIPA(3)/M-NC nanocomposite hydrogel had Young's moduli of 6.5 kPa, 3.8 kPa, and 3.9 kPa, respectively. In contrast, the conventional hydrogel had Young's modulus of 4 kPa. Overall, these findings demonstrate the advantages of using M-NCC, M-SNP, and M-NC crosslinkers in preparing nanocomposite hydrogels. They lead to notable improvements in mechanical properties, making them promising candidates for applications requiring high-performance and flexible materials.