One aspect of the invention relates to hardwood lignin derivatives having an aliphatic hydroxyl content of from about 5.2 mmol/g to about 7 mmol/g lignin, and the preparation method thereof. The lignin derivatives have a desired antioxidant activity characterized by the normalized radical scavenging index (RSI). Another aspect of the invention relates to compositions comprising the hardwood lignin derivative. Another aspect of the invention relates to a use of the hardwood lignin derivatives comprising incorporating the hardwood lignin derivatives into polymer compositions.