A biobased monomer acrylated ricinoleic acid was synthesized from castor oil and copolymerized with methyl methacrylate in miniemulsion forming polymeric nanoparticles. The addition of the biobased monomer led to a decrease in the glass transition temperature of the copolymer and to the formation of a small fraction of gel, resulting in materials with interesting properties for future applications. Display omitted •A biobased monomer acrylated ricinoleic acid was synthesized from castor oil.•The biobased monomer was copolymerized with methyl methacrylate in miniemulsion forming polymeric nanoparticles.•Polymers with lower Tgs were obtained with the addition of the biobased monomer.•The copolymers exhibited interesting properties for future applications as adhesives. Vegetable oils-based polymers are promising materials with application in the industry of coatings and adhesives. Chemically-modified ricinoleic acid obtained from castor oil was used in this study to produce polymeric materials. The adopted strategy consisted in the epoxidation of the double bonds of ricinoleic acid, followed by the ring opening reaction in the presence of acrylic acid to form the acrylated ricinoleic acid (ARA). Free radical copolymerizations of ARA and methyl methacrylate (MMA) were carried out in miniemulsion, resulting in latexes stable over a long storage time. DLS measurements revealed the formation of submicron polymeric particles of different sizes strongly dependent on the fraction of the biobased monomer ARA, exhibiting diameters ranging from approximately 80nm to 150nm, as the ARA fraction was increased up to 80wt%. It was possible to prepare polymers with broad ranges of mass-average molar masses in the range from 1137kDa to 65kDa and glass transition temperatures lying in the interval from approximately 124°C–50°C by varying the concentration of the comonomer ARA. Crosslinked copolymers were obtained by increasing the proportion of ARA.