Hydrophilic Polyisophthalamides Containing Poly(ethylene oxide) Side Chains: Synthesis, Characterization, and Physical Properties

Novel polyisophthalamides containing pendent poly(ethylene oxide) (PEO) sequences were prepared by grafting PEOonto poly(5-hydroxy-isophthalamide)s (HO-PIPAs). First, an optimizedmethod of synthesis was applied to prepare HO-PIPAs,following the rules of the direct polyamidation reaction promotedby triphenyl phosphite and catalyzed by pyridine. Next,the modification of HO-PIPAs was performed by a nucleophilicsubstitution reaction with chlorine-terminated PEO monomethylether of average molecular weight 100, 550, and 1000 g/mol. Themodification (grafting) reaction was optimized to assure virtually100% yield. Polymers behaved as graft or brush-like copolymersof polyisophthalamide (PIPA) and PEO, covering a wide range ofratios of PIPA/PEO. Physical properties, such as solubility, glasstransition temperature, and thermal resistance were determined.Special attention was paid to the affinity of the novel copolymersfor water. It was realized that with a high content of PEO, thematerials could absorb water in amounts exceeding their ownweight. Gravimetric methods and water contact angle measurementswere used to quantify the hydrophilicity of the currentPIPA-g-PEO copolymers.