SBR Styrene butadiene rubber

1. STYRENE-BUTADIENE
RUBBERS
MOHAMMAD ANSAR V
S6

2. INTRODUCTION
 SBR is the co-polymer of styrene and butadiene
 It widely used rubber due to its low cost and good properties
 SBR produced by solution and emulsion process
 Recent years solution SBR is commonly use
 The raw materials are monomers ,emulsifiers ,modifiers ,catalyst ,short stop
,coagulating agent ,antioxidant and antiozonants

3. MONOMER PREPERATION
 STYRENE- styrene prepared by dehydration of ethyl benzene
 BUTADIENE –prepared by dehydration of butane
 Ion oxide or chromia alumina used as catalyst

4. POLYMERISATION
 The polymerization leads to 3 varieties cis , trans and vinyl
 Solution SBR contain higher cis , lower trans content low vinyle content
,linearity and molecular weight distribution compared to emulsion SBR

5. EMULSION POLYMERISATION
 Emulsion protect the initiator from termination so E SBR give high molecular
weight and act as good heat transfer medium
 The removal of unreacted monomer is easier than others
 monomer ,water ,emulsifier and initiator added to reactor
 Potassium peroxydisulfate used as initiator
 Soap used as emulsifier
 For cold SBR reaction done at 5 digree Celsius and hot SBR reaction done at
50 degree Celsius
 After reaching 70 to 75 % conversion short stop added to terminate reaction
and control molecular weight

6. cont
 Hydroquinon used as short stop
 N phenyl beta napthalamine used as antioxidant
For cold SBR
phosphate EDTA used as buffer
Ion and hydro peroxide used as initiator
In these method colored product can be made
The disadvantage is polymer have limited molecular weight

8. SOLUTION SBR
 The polymer have narrow molecular weight distribution
 Less chain branching and high cis content
 Abrasion resistance ,less heat build up ,high resilience and better flex
resistance
 Lithium and alkyl lithium used as catalyst
 Molecular weight controlled by catalyst level and temperature

9. PRPERTIES
 Tg of E SBR IS 50 degree Celsius and Tg of solution SBR slightly less than E SBR
 Number average molecular weight of E SBR 80000 to 110000 and solution SBR
1001000
 Weight average molecular weight of E SBR IS 3.2 to 4 lack

10. COMPOUNDING AND
PROCESSING
 Superior extrusion property than NR
 Processing similar to NR
 Compounding ingredients are sulphur ,antioxidant ,antioxonant ,activator,
accelerator , soaftners ,extenders ,fillers,

11. APPLICATIONS
 The main application of SBR is automobile tyre tred
 It is the widely used synthetic rubber occupy half of synthetic rubber
 It replace NR many applications

12. THANK YOU