Chia-Hsun Chen

Preparation, characterization, thermal, and flame-retardant properties of green silicon-containing epoxy/functionalized graphene nanosheets composites

In this investigation, silane was grafted onto the surface of graphene nanosheets (GNSs) through free radical reactions, to form Si-O-Et functional groups that can undergo the sol-gel reaction. To improve the compatibility between the polymer matrix and the fillers, epoxy monomer was modified using a silane coupling agent; then, the functionalized GNSs were added to the modified epoxy to improve the thermal stability and strengthen the flame-retardant character of the composites. High-resolution X-ray photoelectron spectrometry reveals that when the double bonds in VTES are grafted to the surfaces of GNSs. Solid-state 29Si nuclear magnetic resonance presents that the distribution of the signal associated with the T3 structure is wide and significant, indicating that the functionalization reaction of the silicone in the modified epoxy and VTES-GNSs increases the network-like character of the structures. Thermal gravimetric analysis, the integral procedure decomposition temperature, and limiting oxygen index demonstrate that the GNSs composites that contained silicon had a higher thermal stability and stronger flame-retardant character than pure epoxy. The dynamic storagemodulus of all of the m-GNSs containing composites was significantly higher than that of the control epoxy, and the modulus of the composites increased with the concentration of m-GNSs.

Preparation, thermal stability and flame-retardant properties of halogen-free polypropylene composites

A flame retardant containing phosphorus and nitrogen was prepared. This halogen-free flame retardant was blended with polypropylene (PP) by hot melting to improve the flame-retardant capability and thermal stability of the composites. Fourier transform infrared spectroscopy, energy dispersive X-ray measurements, thermogravimetric analysis, limiting oxygen index (LOI) measurements, and UL-94 measurements were applied to characterize the structure and thermal and flame-retardant properties of the composites. When the flame-retardant concentration was 40 wt%, the LOI value of the composite was 40, passing the V-0 rating of the UL-94 test. The LOI and UL-94 data showed the composites have an excellent flame-retardant property. For a kinetic study of thermal degradation, Ozawa’s method was applied to calculate the activation energies of pure PP and the composites. Analytical results indicate that the composites had higher values, meaning they have better thermal stability.

Synthesis, characterization, and properties of silane-functionalized expandable graphite composites

In this study, synthesis and properties of green flame retardant of silane-functionalized expandable graphite (EG) composites were investigated. The coupling agent was used to improve the interface between the matrix and EG. Fourier transform infrared spectrophotometry and X-ray photoelectron spectroscopy were adopted to characterize the functionalized EG. It was affirmed that 3-aminopropyltriethoxsilane (APTS) has been grafted on EG. The modified EG composites improved thermal property, corresponding to functionalized EG. 29Si-nuclear magnetic resonance and scanning electron microscopies were used to study the structure and the morphology property of the modified EG composites. It showed that flake graphite existed in the matrix. Energy dispersive X-ray analysis indicated that Si atoms appeared due to APTS grafted on EG. The expanded structures of graphite were formed after burning. The foamed layer demonstrated the mechanism of protection of EG. The results present poly(methylmethacrylate)/silane-modified EG(PMMA, poly(methylmethacrylate) composites that have excellent thermal stability and flame-retardant property compared to pure PMMA resin.

Preparation of expandable graphite via ozone-hydrothermal process and flame-retardant properties of high-density polyethylene composites

This work presented the ozone (O3)-hydrothermal process to prepare expandable graphite (EG), which is one kind of halogen-free flame retardant. The results showed the expanded volume of EG using the O3-hydrothermal process (O3-HEG), which is higher than those compared with convectional liquid phase synthesis, ultrasound irradiation, and hydrothermal method. Raman spectra and energy dispersive x-ray were used to analyze the structure and confirm that the EG had been prepared. Scanning electron microscope was utilized to observe the morphology of EG and expanded graphite. Thermogravimetric analysis shows that EG can slowdown thermal degradation of polymer and improve the thermal stability of composites. Limiting oxygen index value of composites with 40 wt% loading of O3-HEG is 33, which is higher than that of high-density polyethylene (HDPE)/natural graphite composite. HDPE composites-containing 30 wt % O3-HEG is capable of passing the V-0 classification and has an anti-dripping behavior.

Preparation, characterization, and flame retardance of high-density polyethylene/sulfur-free expandable graphite composites

In this work, a hydrothermal method was used to prepare a novel, sulfur-free expandable graphite (EG), which was added to high-density polyethylene (HDPE) to improve the flammability and the dripping behavior of composites. Phosphoric acid (H3PO4) was utilized as the intercalating agent, and potassium permanganate and nitric acid were used as the oxidizing agent. EG was investigated using Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectrometry, energy dispersive spectrometry, and scanning electron microscopy. Thermogravimetric analysis, the limiting oxygen index (LOI) and UL-94 were used to examine the thermal and flame-retardant properties of the composites. The results demonstrated that the EG composite exhibited much better thermal stability than pure polymer. Additionally, at 30 wt% EG loading, the LOI value of HDPE/ EG fabrication by H3PO4-hydrothermal method (PEG) was 30, and the flammability standard of UL-94 reached the V0 level, verifying that the EG that was prepared using the H3PO4-hydrothermal process can effectively be used in fireproof composites. The tensile modulus of the composites increased with increasing filler content, while the tensile strength decreased. EG enhanced flexural strength and flexural modulus of HDPE composites but not with high EG loading. The impact strength of the composites was diminished due to the incorporation of EG into HDPE matrix.

Experimental and simulation of PET injection stretch blow molding of a 600ml bottle

Injection stretching-blow molding (ISBM) has been used widely to produce thousands of hollow plastics products, such as drink bottles, automobile tanks, containers, and so on. In this study, both experimental and CAE analysis were carried out to model ISBM of the 26g–600 ml and 28g–600 ml bottles. The experiment results show that 28g–600 ml bottles have more uniform bottle thickness.

EFFECT OF POWDER SURFACE CHARGE ON THE RHEOLOGICAL BEHAVIORS OF POWDERPOLYMER BLENDS

The rheological properties of three powder-binder blends, composed of three powders having distinct powder surface charges mixed with a multicomponent binder containing stearic acid, were compared in this study. The powders were tungsten (W), yittria-stabilized zirconia (YSZ, ZrO 2 -3mol%Y 2 O 3 ), and alumina (Al 2 O 3 ), in the order from an acidic powder surface to a basic powder surface. Interfacial reaction as a consequence of Lewis acid-base reaction determined the rheological properties of the blends. Due to the fact that tungsten has a very strong acidic surface oxide layer, its powder-binder blend exhibited the highest apparent viscosity and highest activation energy of flow though it has the smallest surface area per unit volume. On the other hand, the obvious interfacial reaction between alumina and stearic acid caused this powder-binder mixture to have the lowest apparent viscosity and a low activation energy of flow.