Various types of hydrogen bonds,their temperature dependence and water-polymer interaction in hydrated poly(acrylic acid) (PAA) were systematically investigated using 1H CRAMPS solid-state NMR techniques in the temperature range from 25 ℃ to 110 ℃C.The 1H CRAMPS NMR methods are based on a recently developed continuous phase modulation technique for 1H-1H homonuclear dipolar decoupling.The 1H CRAMPS experiments revealed four types of protons in hydrated PAA which are assigned to protons from the mutually hydrogen bonded COOH groups (1),from the free COOH groups (2),from the COOH groups bounded with water or from water bounded with COOH groups which are undergoing fast chemical exchange mutually (3),and from main chain groups (4),respectively.