Preparation And Application Of Kernel Hyperbranched Polyurethane / Acrylic Resin

Hyperbranched polymers have lots of unique characteristics such as spatial three-dimensional structure, low viscosity, high reactivity, simple to synthetic, and so on. Furthermore, hyperbranched polymers have a large number of terminal functional groups, which can be modified and introduce different reactive groups to prepare different types of hyperbranched polymer. The terminal hydroxy groups of hyperbranched polyurethane are modified into acrylic double bonds, and then hyperbranched polyurethane acrylate(HBPUA) resin is obtained. Hyperbranched polyurethane acrylate not only has the structure characteristics of hyperbranched polymers, but also can be UV curing, which bring a good prospect in light curing field.There are two main methods for preparing UV curable hyperbranched urethane acrylate. One is to synthesize polyester at first, and then modified to introduce urethane and photocurable group; the other is to obtain a hyperbranched polyurethane prepared from diisocyanate reacted with diethanolamine directly, and then modified it. These two methods both will gain better performance hyperbranched urethane acrylate resin.In our study, glycerol and pentaerythritol were used to make core, and isophorone diisocyanate(IPDI)、neopentyl glycol(NPG) and diethanolamine(DEOA) were raw materials to prepare different hyperbranched polyurethane(HBPU-OH) with core, which endcapped by multiple hydroxyl groups. The molecular structure and properties of the HBPU-OHs were characterized. Then,the hyperbranched polyurethane acrylate with core(HBPUA) was synthesized by the reaction of HBPU-OHs and the semiadduct isocyanate-hydroxyethyl acrylate(IPDI-HEA), introduced urethane groups and acrylic double bonds.The structure of HBPUA can be designed, and the number of double bonds was adjustable.Structure and performance of HBPUAs were characterized. Moreover, HBPUAs were added into ordinary and commercialize UV curing resin to make curing film, and then the property of film was studied.The main contents of this paper are the following four points: 1. Synthesis of HBPU-OH(1) A3 reaction intermediates with three terminal NCO groups were prepared by the reaction of glycerol and isophorone diisocyanate(IPDI). A3 reaction intermediates continued to react with diethanolamine(DEOA) to prepare hyperbranched polyurethane(HBPU-0-6) with six terminal hydroxyl groups.(2) Glycerol and isophorone diisocyanate(IPDI) were used to prepare A3 reaction intermediates with three terminal NCO groups. A3 reaction intermediates continued to react with neopentyl glycol(NPG) to prepare hyperbranched polyurethane(HBPU-N-3) with three terminal hydroxyl groups.(3) A4 reaction intermediates with four terminal NCO groups were prepared by the reaction of pentaerythritol and isophorone diisocyanate(IPDI). A4 reaction intermediates continued to react with neopentyl glycol(NPG) to prepare hyperbranched polyurethane(HBPU-N-4) with four terminal hydroxyl groups. 2. Structure study of HBPU-OHFourier transform infrared spectroscopy(FTIR) and NMR(1H-NMR and 13C-NMR) were applied to characterize the structures of the products; Differential scanning calorimetry(DSC) was used to test glass transition temperature of the product; Thermal gravimetric analysis(TG) is adopted to analyze the thermal decomposition course of products; FTIR test results show that, NCO groups was reacted completely, turned to a large number of product hydroxyl groups(-OH), and along with urethane bonds(-NHCOO-); 1H-NMR and 13C-NMR demonstrated this test results; DSC results instructed that, glass transition temperature of the HBPU-OH, which structure introduced chain extender(HBPU-N-3 and HBPU-N-4) were significantly lower than that HBPU-OH without chain extender(HBPU-0-6); TG test indicate that, HBPU with different structure had similar thermal degradation process. 3. Synthesis of HBPUAThe semi-adduct isocyanate-hydroxyethyl acrylate(IPDI-HEA) was prepared from hydroxyethyl acrylate(HEA) and isophorone diisocyanate(IPDI); Then, IPDI-HEA was used to modify HBPU-OH. A UV curable hyperbranched polyurethane acrylate with core(HBPUA) was synthesized after the introduction of double bond. After steps of separation and drying, a white powder product was gained. 4. The structure and performance study of HBPUAFourier transform infrared spectroscopy(FTIR) and NMR(1H-NMR and 13C-NMR) were applied to characterize the structures of the products; Differential scanning calorimetry(DSC) was used to test glass transition temperature of the product; Thermal gravimetric analysis(TG) is adopted to analyze the thermal decomposition course of products; FTIR and NMR indicate that, acrylic double bonds were introducted into the HBPU structure; DSC results instructed that, glass transition temperature of the HBPU, which structure introduced chain extender(HBPU-N-3) were significantly lower than that HBPU without chain extender(HBPU-0-6);Glass transition temperature of HBPUAs are significantly lower than corresponding HBPU; TG test indicate that, HBPUA with different structure had similar thermal degradation process.The four different structure hyperbranched polyurethane acrylic resins with core were added to ordinary and commercial UV light curing resin in different mass ratio(2%, 4%, 6%, 8%, 10%), UV cured, then the comprehensive performance of the composite coating films were studied. Test results show that, after addition of HBPUAs, the mechanical properties of the composite films had some improvement. Compared composite coating film of different HBPUA resin with core: Different plus karyotype HBPUA resin composite coating film performance compared: When the mass amount of all were 10%, the pencil hardness of composite coating film,which containing HBPUA-0-3, HBPUA-0-6, HBPUA-N-3 and HBPUA-N-4, was significantly improved, respectively 4H, 5H, 3H, 4H; Adhesion was slight decrease, namely 2,3,2,3; Impact strength was markedly improved, namely 46,45,50,48; There is no change in flexibility.