تهيه و بررسي پوشش‌هاي پلي يورتاني آب پايه تابش پز شفاف بر پايه‌ي نشاسته اصلاح شده با گليسيديل متاكريلات و نانو ساختار هيدروكسيد دوگانه‌ي لايه‌اي ميان لايه‌اي شده با فيتيك اسيد

Preparation an‎d eva‎luation of UV-Curable waterborne polyurethane coatings based on modified starch with glycidyl methacrylate an‎d layered double hydroxide intercalated with phytic acid

شيمي پليمر

Coatings are recognized as one of the most effective solutions for protecting surfaces against environmental factors, corrosion, an‎d wear, significantly contributing to the durability an‎d performance enhancement of materials. Polymer coatings have gained a special position in various industries due to their lightweight, ease of processing, good adhesion to substrates, an‎d the ability to adjust their chemical structure. However, conventional polymer coatings, which are primarily produced from petroleum sources, face serious limitations due to dependence on fossil resources an‎d environmental issues. Therefore, the development of bio-based coatings derived from natural polymers such as starch, chitosan, alginate, vegetable oils, an‎d polyphenols has gained attention as sustainable alternatives. The inherent weaknesses of natural materials, such as low mechanical properties, sensitivity to moisture, an‎d limited thermal stability, necessitate structural modification an‎d improvement. Strategies such as chemical crosslinking to enhance thermal an‎d mechanical resistance, adding nanomaterials to strengthen properties an‎d create stronger interactions, modifying starch to reduce hydro‎philicity an‎d improve processability, an‎d using water-based polyurethanes with suitable polarity to increase compatibility between the matrix an‎d fillers are considered effective approaches to address these challenges. Polyurethanes have gained a special place due to their unique combination of mechanical properties, flexibility, chemical resistance, an‎d barrier properties. In this context, the development of water-based polyurethanes as a sustainable an‎d environmentally friendly alternative, along with innovative technologies such as ultraviolet radiation curing, which creates a fast, low-energy, an‎d pollution-free process, has opened new horizons in the design of green coatings. In this research, UV-cured water-based polyurethane nanocomposite coatings were synthesized using isophorone diisocyanate, polytetramethylene ether glycol, dimethylol propanoic acid, an‎d hydroxyethyl methacrylate. To simultaneously enhance mechanical an‎d thermal properties, two reinforcing components, including glycidyl methacrylate-modified starch an‎d phytic acid-intercalated layered double hydroxide nanostructures, were added to the system. The surface modification of LDH with phytic acid not only facilitated uniform dispersion in the matrix but also contributed to increased thermal stability by creating a flame-retardant effect an‎d preventing heat transfer. The results of mechanical tests showed that the optimal sample had a tensile strength of 3.46 MPa an‎d an elongation of 410%, indicating the simultaneous preservation of strength an‎d flexibility. Additionally, TGA analysis showed an increase in char yield up to 43.12% an‎d improved thermal stability, confirming the role of interfacial bonds an‎d phase homogeneity. Overall, this synergistic effect between the modified biopolymer an‎d the mineral nanofiller led to the production of a multifunctional, stable, an‎d environmentally friendly coating for advanced industrial applications such as automotive, electronics, an‎d packaging.

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