Consider the following statements about emulsion SBR and solution SBR. I. Solution SBR has higher content of non-rubber materials than emulsion SBR II. Solution SBR has higher molecular weight but broader molecular weight distribution than emulsion SBR III. Solution SBR has higher cis-1,4-polybutadiene content than emulsion SBR Which of the following statements are true?

Correct Answer: III only
Solution SBR has a lower content (nearly 2%) of non-rubber materials while emulsion SBR has non-rubber materials in excess of 10%. Solution SBR has narrower molecular weight distribution, higher cis-1,4-polybutadiene content and higher molecular weight than emulsion rubber.