Jun Gang Gao

UV-Curable Coating of Epoxy-Acrylate/Polyurethane-Acrylate Nanocomposites Modified with V-POSS

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.

Synthesis of Novel Drug Benvitimod

Benvitimod (3,5-dihydroxy-4-i-propylstilbene) is a novel drug developed for common skin disorders such as atopic dermatitis by Welichem Biotech Inc. in Canada and Celestial Pharmaceuticals (Shenzhen) Co. Ltd. in China. But the ideal synthesis method is not reported so far. Herein an efficient synthesis method which is operated under the mild conditions is reported. According this route, the total yield will reach 40.3 - 48.1% and the benefits of the improved method are easily operating and environment friendly.

Dynamic Mechanical and Thermal Behavior of UV-Curable Coating of Glycidyl Methacrylate /Polyurethane-Acrylate Modified with MAP-POSS

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 Tp 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.

Synthesis and Thermal Properties of a Boron-Containing Bisphenol-S Formaldehyde Resin

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 (Tg) of BBPSFR is higher 104°C than that of bisphenol-S formaldehyde resins (BPSFR); the initial degradation temperature (Ti ) increases about 43°C; thermal degradation rate decrease and thermal stability increase significantly.

Synthesis and Properties of Hybrid Curing Siloxane Modified Epoxy Resin/Polyurethane Acrylate Coating

In order increasing properties of polyurethane acrylate coating, the epoxy resin/ polyurethane acrylate coating was prepared by UV and thermal dual curing with diphenyliodonium salt. The curing reaction and kinetics was investigated by UV-radiation and DSC, and the influence of the siloxane of methylacryloylpropyl-trimethoxysilane (MAPTMS) content on the properties of coating was determined by DMA and other physical methods. The results showed the hardness and glass transition temperature Tg of the coating film increased with the increasing MAPTMS content and the coating has good adhesion. When the content of MAPTMS reach 12 wt%, the Tg is the highest, which is 8.2°C higher than the before; When the triethylene glycol divinyl ether (DVE-3) can change the reaction from UV free radical/cationic reaction into thermal radical/cationic reaction, and can be described by autocatalytic Šesták-Berggre model (S-B) and the average activation energy Ea is 70.55 kJ/mol.

Influence of Polyols as a Co-Stabilizer on Stabilization Efficiency of Calcium/Zinc Stabilizers to PVC/ACS Blend

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.

Preparation and Properties of Emulsion Coating of Polyacrylate Modified by In-Situ Nano-Hybrid Silica

The polyacrylate emulsion coating modified by nano-silica was prepared by In-situ method. Tetraethoxysilane (TEOS) was added as the precursor of SiO2 in the late of the emulsion polymerization. The structure and properties of emulsion and latex film were characterized. The results showed that the nano-hybrid silica/polyacrylate emulsion coating with good performance can be prepared by In-situ method. FTIR analysis indicated that the -Si-O-Si- structure has embodied in the coating film. The particle diameter of emulsion is 378nm when nano-SiO2 content is 6% and the dispersing index is 0.164. The mechanical loss peak temperature (Tp) of coating film with 6% nano-SiO2 is 60.6°C which increase 6°C than pure emulsion film. The nano-hybrid emulsion coating has a good performance, such as good acid-alkali resistance and hardness.

Rheological Behavior and Mechanical Properties of PVC/V-POSS Nanocomposites

The poly(vinylchloride) (PVC) nanocomposite was prepared by melt mixed of PVC with polyhedral oligomeric silsesquioxanes containing vinyl group (V-POSS). The rheological behavior of V-POSS/PVC nanocomposites was investigated by torque rheometer and capillary rheometer. The influences of composition of blends, shear rate, shear stress on melt apparent viscosity and non-Newtonian index (n) were discussed. The dynamic mechanical properties, mechanical properties and morphology were determined. The result shows that the plastic time of nanocomposites decreases while melt viscosity increases with increasing V-POSS content. V-POSS has a good compatibility with PVC. The nanocomposites have better impact strength with increasing V-POSS content. V-POSS can use as process aid and impact aid at appropriate contents.

Systhesis, Curing and Thermal Propertied of Boron-Containing o-Cresol-Formaldehyde Resin

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.

The Preparation of (E)-Resveratrol Nanoemulsion and In Vitro Release

Here a novel procedure to prepare stable (E)-resveratrol nanoemulsion is reported. The optimum (E)-resveratrol nanoemulsion formulation was sifted based on the pseudo ternary phase diagrams and particle size distribution. An optimized prescription was given as (E)-resveratrol 0.35%, EL-40 22.6%, 1,2-propylene glycol 5.03%, IPM 9.21% and water 62.81% (mass ratio), with the mean particle size 47.3 nm. The morphology of the (E)-resveratrol nanoemulsion was characterized by TEM. The test results demonstrate that the nanoemulsion could dramatically improve the stability and release of (E)-resveratrol.