| Summary: | Bio-based cross-linkers can fulfill the role of enhancing additives in bio-sourced curable materials that do not compare with artificial resin precursors. Isosorbide dimethacrylate (ISDMMA) synthesized from isosorbide (ISD) can serve as a cross-linker from renewable sources. Isosorbide is a bicyclic carbon molecule produced by the reaction modification of sorbitol and the optimal conditions of this reaction were studied in this work. The reaction temperature of 130 °C and 1% <i>w</i>/<i>w</i> amount of <i>para</i>-toluenesulfonic acid (<i>p</i>-TSA) were determined as optimal and resulted in a yield of 81.9%. Isosorbide dimethacrylate was synthesized via nucleophilic substitution with methacrylic anhydride (MAA) with the conversion of 94.1% of anhydride. Formed ISD and ISDMMA were characterized via multiple verification methods (FT-IR, MS, <sup>1</sup>H NMR, and XRD). Differential scanning calorimetry (DSC) proved the curability of ISDMMA (activation energy <i>E<sub>a</sub></i> of 146.2 kJ/mol) and the heat-resistant index of ISDMMA (<i>T<sub>s</sub></i> reaching value of 168.9) was determined using thermogravimetric analysis (TGA). Characterized ISDMMA was added to the precursor mixture containing methacrylated alkyl 3-hydroxybutyrates (methyl ester M3HBMMA and ethyl ester E3HBMMA), and the mixtures were cured via photo-initiation. The amount of ISDMMA cross-linker increased all measured parameters obtained via dynamic mechanical analysis (DMA), such as storage modulus (<i>E’</i>) and glass transition temperature (<i>T</i><sub>g</sub>), and the calculated cross-linking densities (<i>ν<sub>e</sub></i>). Therefore, the enhancement influence of bio-based ISDMMA on resins from renewable sources was confirmed.
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