29898
Hydrogen bonding between polybenzoxazine and chitosan structures was also observed .
 Chemical: Hydrogen; Chemical: polybenzoxazine
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: Hydrogen, polybenzoxazine 
Answer:
 Chemical: Hydrogen; Chemical: polybenzoxazine