14890
The polynorbornene - backbone - based BrBCPs containing approximately equal volume fractions of each block self - assembled into highly ordered lamellae with domain spacing ranging from 20 to 240 nm by varying molecular weight of the backbone in the bulk state , as revealed by small - angle X - ray scattering ( SAXS ) .
 Chemical: polynorbornene
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
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Answer:
 Chemical: polynorbornene