ABSTRACT
Hydrogels have gained significant attention in scientific communities for their versatile applications, but several challenges need to be addressed to exploit their potential fully. Conventional hydrogels suffer from poor mechanical strength, limiting their use in many applications. Moreover, the crosslinking agents used to produce them are often toxic, carcinogenic, and not bio-friendly. This study presents a novel approach to overcome these limitations by using bio-friendly modified nanocrystalline cellulose as a crosslinker to prepare highly stretchable and tough thermosensitive hydrogels. The surface of nanocrystalline cellulose was modified with 3-methacryloxypropyltrimethoxysilane (MPTS) to obtain modified nanocrystalline cellulose (M-NCC) crosslinker and used during free radical polymerization of thermosensitiveN-isopropyl acrylamide (NIPA) monomer to synthesize NIPA/M-NCC hydrogel. The resulting nanocomposite hydrogels exhibit superior mechanical, thermal, and temperature-responsive swelling properties compared to conventional hydrogels prepared with traditional bi-functionalN,N'-methylene bis (acrylamide) (MBA) as a crosslinker. The elongation at break, tensile strength, and toughness of the NIPA/M-NCC hydrogels significantly increase and Young's modulus decrease than conventional hydrogel. The designed M-NCC crosslinker could be utilized to improve the mechanical strength of any polymeric elastomer or hydrogel systems produced through chain polymerization.
ABSTRACT
Biodegradable polymeric films have great potential as alternatives to synthetic polymeric films to reduce environmental pollution. Plasticizing agents and nanofillers can improve the mechanical properties of polymer-based composites, resulting in materials with better flexibility and extensibility. Starch, a natural polymer, can be produced at low cost and on a large scale from abundant and inexpensive agricultural resources like potatoes. The aim of the present work was to fabricate mechanically strong and thermally stable potato starch films reinforced with different types of plasticizers and nanoclays at different concentrations. Different types of plasticizers such as water, glycerin, ethylene glycol, sorbitol, and formamide and three types of clays such as montmorillonite, hectorite, and kaolinite at various concentrations were used to prepare potato starch-based nanocomposite films. The films were prepared using a very simple solution casting process. The mechanical properties and thermal stabilities of nanocomposite films significantly improved using montmorillonite, hectorite, and kaolinite clays. The water uptake percentage of the fabricated films decreased with addition of plasticizers and further decreased with addition of different types of clays. The structural and morphological changes of the fabricated films in the presence of plasticizers and nanoclays were correlated in detail with their mechanical properties, crystallinity, biodegradability, thermal stability, and water absorption capacities.
