To increase physical properties of the SBR/BR blend?

[joysop]

Hi,
I know BR is partially miscible with SBR.
To increase their miscibility that serves to improve physical properties, what can I do?
Thanks...

 

[joysop]

I'm going to use BR of 20 pbw to SBR.

 

[hoidap]

please masticate BR and SBR to have a similar viscosity before blending them together. But too high viscosity rubber reduce shear force, decrease filler dispersion.
Due to different structure, BR will hold more filler loading than SBR.

 

[joysop]

Please make sure for me wheather too high viscosity rubber reduces shear force and decreases filler dispersion.
Is the opposite correct? Low viscosity makes rubber reduce shear force and decrease filler dispersion?
Please make it correct for me.
Anyway your post helps me a lot. Thank you....

 

[GrahamBennett]

Joysop - you are correct. A higher viscosity will mean more shear and better dispersion.

By the way you should not have to masticate either the SBR or BR to reduce the viscosity. You can add them both together at the beginning of the mix and allow the mixer to run for 30secs or so to warm them up before adding the other ingredients.