We Claim:
1. A method for synthesis of pinene based resin grafted styrene butadiene
rubber comprising:
a) adding a pinene based resin along with styrene butadiene rubber in a weight ratio of resin: rubber in a range from 0.25 to 1.5: 1.0, into a solvent reaction medium to obtain a reaction mixture;
b) heating the reaction mixture and maintaining a temperature of 70°C to 90°C, to obtain a heated reaction mixture;
c) adding a free radical initiator to the heated reaction mixture at a temperature of 70°C or above;
d) allowing the reaction to carry on for 30 minutes to 120 minutes to obtain a grafted styrene butadiene rubber in soluble form in the reaction mixture;
e) coagulating the grafted styrene butadiene rubber from the reaction mixture by adding a polar solvent;
f) collecting the coagulated grafted styrene butadiene rubber on glassware to separate the grafted styrene butadiene rubber from the polar solvent;
g) drying the grafted styrene butadiene rubber to obtain the modified styrene butadiene rubber in solid form.

2. The method as claimed in claim 1, wherein the pinene based resin is selected from polyterpene resin, terpene phenolics, styrenated terpenes or mixture thereof.
3. The method as claimed in claim 2, wherein the pinene based resin has a softening point in the range from 115°C and 150°C.
4. The method as claimed in claim 1, wherein the solvent reaction medium in step (a) is toluene.
5. The method as claimed in claim 1, wherein the free radical initiator is organic peroxide or a mixture thereof.
6. The method as claimed in claim 5, wherein the free radical initiator is benzoyl peroxide.

7. The method as claimed in claim 6, wherein the benzoyl peroxide is in the range of 0.2 to 0.6 wt % of the total reactants.
8. The method as claimed in claim 1, wherein the polar solvent in step (e) is acetone.
9. A pinene based resin grafted styrene butadiene rubber obtained according to the method as claimed in claim 1.