Synthesis and properties of p(NIPA-co-NVP)/clay hydrogels by radiation polymerization

In this study, hydrogels of P(NIPA-co-NVP)/clay were synthesized by γ-ray radiation. Different thermo-sensitive hydrogels were made under different experimental conditions such as dose, monomer ratio, and content of clay. X-ray diffraction shows that the layer distance between Na-clays is changed from 1.6 to 2.7 nm because Na-clay pieces can be intercalated or exfoliated by HTMAB, and that between P(NIPA-co-NVP)/clay pieces is 3.4 nm. The swelling property tests show that the LCST of P(NIPA-co-NVP) is higher than PNIPA. With the increase of NVP content, LCST is higher. As the ratio of NIPA/NVP is 95/5, hydrogel shows the best swelling property and LCST is 37°C. LCST of P(NTPA-co-NVP)/clay hydrogel is not changed, but the strength and swelling properties are better.