Synthesis and characterization of novel thermoplastic poly(oligophosphazene-urethane)s

A facile preparation of a novel non-leaching antimicrobial waterborne polyurethane leather coating functionalized by quaternary phosphonium salt

The aim of this research is to develop a novel non-leaching antimicrobial waterborne polyurethane (WPU) leather coating material with covalently attached quaternary phosphonium salt (QPS). The structure of the QPS-bearing WPU has been identified, and their thermal stability, mechanical property, and antimicrobial performance have been investigated. The results reveal that the incorporation of QPS slightly reduces the thermal stability of WPU material but would not affects its usability as leather coating. Despite the presence of hydrophobic benzene in QPS structure, the strong hydration of its cationic groups leads to the increased surface contact angle (SCA) and water absorption rate (WAR) of the films, suggesting that the water resistance of the films needs to be improved for the purpose of leather coatings. Antibacterial tests demonstrate that when the QPS content is 20 wt%, QPS-bearing WPU shows effective antimicrobial activity against bacteria. The WPU containing QPS prepared in this study is a non-leaching antimicrobial material and has great potential application as leather coating.

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Evaluation of thermo-mechanical, dielectric and corrosion resistant properties of cardanol benzoxazine-epoxy based hybrid composites: A very low temperature curing pre-polymer for high performance paint related applications

In the present work, the hybrid siloxane-based cardanol-benzoxazine-epoxy (1:1 ratio) matrix (SBCBz-EP) capable of curing at substantially low temperature when compared with that of conventional benzoxazines was prepared and characterized. The matrix SBCBz-EP was reinforced with varying weight percentages (1, 3 and 5 wt%) of hydroxyl-terminated cyclotriphosphazene (HTCP) and the resulting hybrid composites were characterized by modern analytical methods, which can be used for paint-related applications due to their low-temperature curing behaviour. Data obtained from differential scanning calorimeter analysis infer that the glass transition temperature of the hybrid matrix (SBCBz-EP) and HTCP reinforced with 1, 3 and 5 wt% composites was 73°C, 75°C, 82°C, and 88°C, respectively. The polymerization temperature obtained for SBCBz-EP matrix and HTCP-reinforced hybrid composites was considerably lower than that of conventional benzoxazines. The present hybridization approach of benzoxazine and epoxy paves an avenue to alleviate the deficient characteristics of both industrially valuable resins namely high curing temperature and brittle behaviour of benzoxazines and also to improve thermal stability, mechanical strength and flame-retardant behaviour of epoxy resins. Data obtained from mechanical, dielectric, thermal stability and corrosion-resistant studies indicate that the properties of hybrid composites (HTCP/SBCBZ-EP) were enhanced to an appreciable extent according to the wt% of HTCP and it can be suggested that these hybrid composite materials can be used in the form of adhesives, sealants, encapsulants and water-resistant coatings for high performance industrial applications.