Chemical Modification Of DCPD Petroleum Resin By Photo-induced Click Chemistry

Petroleum resin is a kind of thermoplastic resin with the molecular weight ranging from 300 to 3000 g/mol, which is usually synthesized by C5 or C9 fractions (separated from the ethylene cracking unit). According to different raw materials and properties, petroleum resin can be divided into C5 petroleum resin, C9 petroleum resin, C5/C9 copolymer petroleum resin, and DCPD petroleum resin. Due to its excellent adhesive properties, acid/alkali resistance, quick drying performance, and the low price, the petroleum resin has been widely applied to the field of coating, printing ink, rubber, road marking paint and hot melt etc. However, many challenges still remained to be addressed, such as low softening point, brittleness, poor compatibility with polar resins, and high processing temperature. To overcome the disadvantages of the petroleum resin, chemical modification is usually required to improve the property of petroleum resin. However, traditional modification methods are usually high energy consumption and low efficiency. Furthermore, the petroleum resin was usually used as a simple physical additive at the beginning of the modification. So those may lead to shortcomings of the performance of the modified products, such as the coating is easy to peel off, the solvent resistance of the coating is not strong, the strength of the coating is not good. In this thesis, we developed an efficient and energy-saving chemical modification route of petroleum resin based on click chemistry, and we also found that the modified petroleum resin could be cured under UV irradiation. The main research work of this thesis is as follows:(1) Synthesis of DCPD-COOHA photo-induced click chemistry of 3-mercaptopropionic acid with DCPD petroleum resin was conducted at room temperature, and the obtained product was denoted as DCPD-COOH. The structure and composition of DCPD-COOH was characterized by 1H NMR and FT-IR spectrometry. Reaction conditions were optimized by an acid titration method with KOH-ethanol solution as the titration solution and phenolphthalein as an indicator. We found that the product exhibited good comprehensive performance and high acid value when the reaction mixture was conducted at room temperature for 2 hr in the presence of 2 mol% photoinitiator (Darocur1173) and 1-fold excess of 3-mercaptopropionic acid.(2) Synthesis of DCPD-AIn the presence of triphenyl phosphine, the DCPD-COOH was allowed to react with glycidyl methacrylate (GMA) to transform to an acrylate petroleum resin, denoted as DCPD-A. The structure and composition of DCPD-A was characterized by 'H NMR and FT-IR spectrometry. Reaction conditions were optimized by 1H NMR internal standard method. We found that the obtained product exhibited good comprehensive performance when the reaction was conducted at 105 ? for 3 hr in the presence of 1.5wt.% catalyst. The photo-curing property of DCPD-A was investigated, and a UV-cured thin film with 0 level of adhesion and 2H of pencil hardness was prepared.(3) Modification of DCPD petroleum resin by long chain segment and polar groupThe photo-induced click chemistry of n-dodecanethio with DCPD petroleum resin was conducted at room temperature, the obtained product was denoted as DCPD-S. The photo-induced click chemistry of isooctyl 3-mercaptopropionate IOMP with DCPD petroleum resin was conducted at room temperature, the obtained product was denoted as DCPD-P. Structures of DCPD-S and DCPD-P were characterized by 'H NMR spectrometry. The viscosity of DCPD-S was studied, and the results showed that the viscosity of DCPD-S could be decreased to 1.3 Pa.s at 80 ?, which greatly reduces the processing temperature. The compatibility of DCPD-P and DCPD-COOH was also investigated, and the results show that the modified petroleum resin has good compatibility with polar solvents.