20874
Here , controlled radical polymerization is used to synthesize well - defined PVA , which has enabled us to obtain the first quantitative structure - activity relationships , to probe the role of molecular weight and comonomers on IRI activity .
 Chemical: PVA
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: PVA