6777
The carbon black and graphene filaments were brittle and fractured easily , but the copper-based filament could be bent at least 500 times with little change in its resistance .
 material: carbon black; material: graphene filaments; machanical property: brittle; material: filament; material: be; machanical property: resistance
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
 Entities: carbon black, graphene filaments, brittle, filament, be, resistance 
Answer:
 material: carbon black; material: graphene filaments; machanical property: brittle; material: filament; material: be; machanical property: resistance