2310
Single - walled carbon nanotubes are grafted with polystyrene chains employing a graft - to protocol .
 Chemical: carbon; Chemical: polystyrene
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: carbon, polystyrene 
Answer:
 Chemical: carbon; Chemical: polystyrene