Papers by Author: Jun Gang Gao

Abstract: In order to prepare an anaerobic adhesive which has a good heat resistance, the epoxy acrylate of polyhedral oligomeric silsesquioxanes (POSSEA) -containing was synthesized and was used as a as main composition of adhesive monomers. The anaerobic adhesive was prepared from POSSEA, 2-hydroxyethylacrylate, acrylate, and selecting a suitable redox initiating system. The correlated properties were determined by DSC, TGA, so on. The results show that the appeared reaction order of curing reaction was 0.87 and activation energy E_a was 59.9 kJ/mol. The initial degradation temperature of this adhesive is 302 °C, and followed first order kinetics. The adhesive shear strength of steel plate is 24.6MPa. The results indicated that this anaerobic adhesive has well bonding strength and high temperature resistance property.

Abstract: The epoxy resin (ER) and 2,3-epoxypropoxypropytrimethoxysilane (KH-560) were used to prepare alkyd resin (AR) insulating coating. The modified waterborne alkyd resin insulating coating was prepared. The dynamic mechanical properties, thermal properties and electrical properties of the composites were characterized by DMA, TG, et al. The results show that the tertiary amine has a good catalyzing effect for this reaction. When the mass ratio of AR with ER is 1 : 1, the glass transform temperature T_g of material is 64.6 °C. When the content of KH-560 is 5% mass fraction of the alkyd resin, the T_g of composites increase 5.6 °C, the initial degradation temperature increased by 63.78 °C; The r_s and r_v of composites are between 10⁹ ~ 10¹² MΩ; the ε and tanδ is between 0.6553 ~ 0.9975 and 0.0025-0.0036, respectively. The pencil hard degree and the impact strength of coating film are all over 5H and 40N, respectively.

Abstract: Polyhedral oligomeric silsesquioxanes epoxy resin (G-POSS) was prepared from 2,3-glycidyloxypropyl-trimethoxysilane (GTMS) by hydrolytic condensation. Thermal properties and electrical properties and UV-curing gel rate of G-POSS/epoxy resin (ER)/unsaturated polyester (UP) nanocomposites using diphenyliodide hexafluorophosphate (DPI·PF6) as initiator of curing reaction were investigated. The results showed that curing process of G-POSS/ER/UP is the double hybrid free radical/cationic polymerization. The gel rate of all the samples is more than 90%. G-POSS would decrease the electrical resistivity and increases the dielectric constant of the complex curing materials. Thermal stability is increased with the addition of G-POSS.

Abstract: In order to prepare good thermal stabilizer for PVC/ACS blends, the Congo red methods was adopted to determine the thermal stabilizing time of blends and study the synergy effect between polyols and Ca/Zn stabilizer for PVC/ACS blends. The rheological behaviors and dynamic mechanical properties of PVC/ACS blends were investigated by rotational rheometer and dynamic mechanical analyzer (DMA). The results showed that the different polyols have different influences on the thermal stability, melt viscosity, dynamic mechanical properties of PVC/ACS blends. The pentaerythritol has a good synergy effect with Ca/Zn stability and the PVC/ACS blend has a lower melt viscosity.

Abstract: In ouder to prepare the waterborne UV-curable polyurethane acrylate coatings, the anionic polyurethane acrylate emulsifier and bisphenol-S eopxy acrylate were synthesized. The curing process, kinetics and properties of waterborone UV-curable epoxy acrylate/polyurethanes acrylate coating were investigated by FTIR, DSC and DMA. The results show that the static initial curing temperature T_i is 52.36 oC, peak temperature T_p is 71.58 oC, the finished temperature T_f is 89.15 oC. The curing reaction can be described by two-parameter autocatalytic Šesták-Berggren (S-B) model.This coating has a better UV-curing property. The dynamic mechanical analysis showed that the glass transition temperature T_g of coating film is 52.70 oC.

Abstract: Boron-containing bisphenol-S formaldehyde resin (BBPSFR) was synthesized by formalin method. The structure and thermal properties of BBPSFR were characterized by ¹H NMR, FTIR, torsional braid analysis (TBA) and thermogravimetric analysis (TGA), respectively. The results showed that the borate had formed, and the six-member ring containing boron-oxygen coordinate structure also formed during the curing process. The glass transition temperature (T_g) of BBPSFR is higher 104°C than that of bisphenol-S formaldehyde resins (BPSFR); the initial degradation temperature (T_i ) increases about 43°C; thermal degradation rate decrease and thermal stability increase significantly.

Abstract: In order to improve the properties of boron-containing phenol-formaldehyde resin (BPFR), the tetrabromo-bisphenol A epoxy resin (TBBPAER) was used to cure BPFR. The curing mechanism, thermal properties and the fire resistance of TBBPAER/BPFR were investigated by fourier transform infrared spectrometer (FTIR), thermal gravimetric analysis (TGA), torsional braid analysis (TBA) and the oxygen index method. The results show, -OH of -C₆H₄-CH₂OH and -C₆H₄OH reacts with the epoxy group. With the increase in the amount of BPFR, the thermal properties get better. When the additive amount of TBBPAER is 10 wt%, this material has best thermal stability at high temperature and higher temperature of loss bromine. The glass transition temperature (T_g) is 223.2 °C and the LOI is 68.5.

Abstract: UV-curable bi-component coating of glycidyl methacrylate (GMA)/polyurethane –acrylate (PUA) modified with the methylacryloylpropyl polyhedral oligomeric silsesquioxanes (MAP-POSS) were prepared. The dynamic mechanical properties and thermal behavior of nano-hybrid coating (GMA/PUA/MAP-POSS) were characterized with dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA) and the Fourier transform infrared spectrometer (FTIR). The results indicate the three components have very good compatibility and can co-cure in UV-radialization by a free radical polymerization. The addition of MAP-POSS enhanced the thermal properties, the mechanical loss peak temperature T_p is 85.5°C when the amount of MAP-POSS is 10wt%, which is increased by 12.6 °C than the pure system. When the content of MAP-POSS is 20wt%, thermal decomposition temperature in the initial stages was increased by 7 °C than that of the pure GMA/ PUA.

Abstract: The boron-containing o-cresol-formaldehyde resin (BoCFR) with different amounts of boron was synthesized from o-cresol, boric acid and formaldehyde solution. The curing process of resin was by characterized by FTIR. The thermal properties and dynamic mechanical properties of resin were investigated. The results show that the borate has formed. The BoCFR has a better thermal stablitity. The residual rate of BoCFR is 30-40 % at 900 oC, which is higher about 400 oC than ordinary o-cresol-formaldehyde resin (o-CFR). The maximal mechanical loss temperature (Tp) is higher 30-38 oC than o-CFR. The weight loss of BoCFR can be main divided two stages. The main thermal degradation reaction follows first order kinetics.

Abstract: UV-curable bi-component coating of epoxy-acrylate/polyurethane-acrylate modified with polyhedral oligomeric silsesquioxane containing vinyl group (V-POSS), and UV-cured process and kinetics were investigated by FTIR, DSC, and DMA. The results show that this coating has a good UV-curable property, and the two components have very good compatibility and can co-cure in free radical polymerization. The curing reaction can be described by a two-parameter autocatalytic Šesták-Berggren (S-B) model. The modified UV-curable coating has good adhesive strength for steel and hardness. The mechanical loss peak temperature Tp is highest when the content of V-POSS is 60%, which is increased by 5.2 oC than the pure system.