Shoubing Chen

Stimuli-responsive composite particles as solid-stabilizers for effective oil harvesting.

The polymer-grafted magnetic composite particles have been synthesized and developed to harvest oil by use of their speical wettability. Different from gravity-driven oil-water separation, the prepared polymer brushes-grafted magnetic composite particles can act as solid-stabilizers that diffuse to the oil-water interfical region and effectively minimize the direct oil-water interfical area by volume exclusion, whereas the magnetic Fe3O4 core allows easy separation of Pickering emulsions from oil-water mixture under an external magnetic field. When the emulsions were heated from room temperature to 50 °C, the coil-to-globule transition of poly(N-isopropylacrylamide) (PNIPAM) acts as the driving force for the destabilization of the emulsion, thereby achieving the release of oil. The novel materials can be used in aspects of oil-water separation, inducing oil droplet transport and release of lipophilic substrates.

Dynamic mechanical properties of polysiloxane-modified, castor oil-based polyurethane/epoxy interpenetrating polymer network composites

A series of hydroxyl-terminated poly dimethyl siloxane (HTPDMS)-modified polyurethane (PU)/epoxy resin (EP) graft interpenetrating polymer network (IPN) composites were prepared. The morphologies of impact fracture surfaces, tensile and impact strengths, damping properties as well as thermal stability properties of the HTPDMS modified IPN composites were studied systematically. The results revealed that the impact strength of the IPN composites could be significantly improved after the incorporation of HTPDMS, whereas the tensile strength of the composites was impaired when the HTPDMS content were more than 5%. The studies also showed that the addition of HTPDMS can improve the damping properties of pure PU/EP IPN and can improve the thermal decomposition temperature. It is expected that the modified IPN composites may be used as structural damping materials.

Mechanical, damping, and thermal properties of calcium sulfate whisker-filled castor oil-based polyurethane/epoxy IPN composites

A series of calcium sulfate whiskers (CSW)-filled, castor oil-based polyurethane/epoxy resin graft interpenetrating polymer network (IPN) composites were prepared. The tensile and impact strengths, fractured surfaces, damping properties, and thermal stability of the IPN composites were studied systematically in terms of composition. Results revealed that the addition of CSW can significantly improve the tensile strength though the impact strength was impaired. The damping properties were the best when the CSW content was 3%. The thermal decomposition temperature was also improved by the incorporation of CSW. It is expected that the CSW-filled IPN composites may be used as structural damping materials.A series of calcium sulfate whiskers (CSW)-filled, castor oil-based polyurethane/epoxy resin graft interpenetrating polymer network (IPN) composites were prepared. The tensile and impact strengths, fractured surfaces, damping properties, and thermal stability of the IPN composites were studied systematically in terms of composition. Results revealed that the addition of CSW can significantly improve the tensile strength though the impact strength was impaired. The damping properties were the best when the CSW content was 3%. The thermal decomposition temperature was also improved by the incorporation of CSW. It is expected that the CSW-filled IPN composites may be used as structural damping materials.

Physical properties of aramid fiber reinforced castor oil-based polyurethane/epoxy resin IPN composites:

A series of organic aramid fiber filled castor oil-based polyurethane/epoxy resin graft interpenetrating polymer network (IPN) composites were prepared. The tensile and impact strengths, impact fractured surfaces, damping properties and thermal stability of the IPN composites were studied systematically in terms of composition. Results revealed that the addition of aramid fiber can significantly improve not only the tensile strength but also the impact strength. The damping properties were better when the aramid fiber content were 5% and 7%. The thermal decomposition temperature was also slightly improved by the incorporation of aramid fiber. It is expected that the aramid fiber modified polyurethane/epoxy resin IPN composites may be used as structural damping materials.

Damping, Thermal, and Mechanical Properties of Polycaprolactone-Based PU/EP Graft IPNs: Effects of Composition and Isocyanate Index

A series of polycaprolactone (PCL)-based polyurethane (PU)/epoxy resin (EP) graft interpenetrating polymer networks (IPNs) were prepared and their damping propertiesand thermal stability, as well as mechanical properties, were systematically studied in terms of composition and the values of the PU isocyanate index (R). The morphologies of the PU/EP IPNs were observed by scanning electron microscope (SEM) and atomic force microscope (AFM) characterization and the relationship between the morphologies and the properties is also discussed. The damping properties and thermal stability measurements revealed that the formation of PU/EP IPNs could significantly improve not only the damping properties but also the thermal stability. Meanwhile, the mechanical tests showed that the tensile strengths of the IPNs decreased, while their impact strengths increased with increasing PU content. The value of the PU isocyanate index also had significant impacts on the properties of the IPNs when the PU to EP ratio was fixed, which could be an effective means for manipulating the fabrication of PU/EP IPNs. From the results obtained, the PCL-based PU/EP IPNs hold promise for use in structural damping materials.

Damping Properties of Polyurethane/Epoxy Graft Interpenetrating Polymer Network Composites Filled with Short Carbon Fiber and Nano-SiO2

A series of short carbon fiber (CF) and nano-SiO2 filled polyurethane (PU)/epoxy resin (EP) graft interpenetrating polymer network (IPN) composites were prepared. The damping properties as well as tensile and impact strength of the IPN composites were studied systematically in terms of composition. Results revealed that the addition of short CF and nano-SiO2 can significantly improve the damping properties of pure PU/EP IPN, particularly at higher frequencies. Mechanical tests showed that the tensile strength of the IPN composites was improved after the incorporation of short CF and nano-SiO2, while the impact resistance of the composites was impaired after the addition of CF and higher content (beyond 1 wt%) of nano-SiO2. It is proposed that the CF and nano-SiO2 filled IPN composites would be useful as structural damping materials.

Polydimethylsiloxane-toughened PU/EP IPN composites loaded with carbon nanotubes: Damping, thermal, and mechanical properties

A series of HTPDMS-toughened castor oil-based PU/EP-graft IPN composites loaded with multi-walled CNTs were prepared. The damping properties, thermal stability, tensile and impact strengths, as wel...A series of HTPDMS-toughened castor oil-based PU/EP-graft IPN composites loaded with multi-walled CNTs were prepared. The damping properties, thermal stability, tensile and impact strengths, as well as fractured surfaces of the modified IPN composites were studied systematically. Results revealed that the addition of CNTs can significantly improve the damping capacity especially when the CNTs content was 0.5%, though the thermal decomposition temperature decreased slightly. The tensile strength increased by more than 40% when the CNT contents were 0.3% and 0.5%. When the CNTs content was 0.1%, the impact strength was also improved. It is expected that the modified composites may be used as structural damping materials.

Tribological Properties of Hydroxyl-Terminated Liquid Nitrile Rubber-Modified Polyurethane/Epoxy Interpenetrating Polymer Network Composites

A series of castor oil-based polyurethane (PU)/epoxy resin (EP) graft interpenetrating polymer network (IPN) composites modified by two kinds of hydroxy-terminated liquid nitrile rubber (HTLN) was prepared. A systematic investigation of the tribological properties of the two kinds of HTLN-modified PU/EP IPN composites was carried out through a pin-on-disk arrangement under dry sliding conditions. Experimental results revealed that the incorporation of HTLN can improve the friction and wear properties of PU/EP IPN significantly. Both the friction coefficient and wear loss decreased with increasing content of HTLN. The worn surfaces of the samples were analyzed using scanning electron microscope and a three-dimensional (3D) noncontact surface-mapping profiler; the results showed that the worn surfaces of the PU/EP IPN composites became smooth when the HTLN was added. The mechanisms for the improvement of tribological properties are discussed.

Physical Properties of Micro Hollow Glass Bead Filled Castor Oil-Based Polyurethane/Epoxy Resin IPN Composites

ABSTRACT A series of micro hollow glass beads (HGB) filled castor oil-based polyurethane/epoxy resin graft interpenetrating polymer network (IPN) composites were prepared. The tensile and impact strengths, impact fractured surfaces, damping properties and thermal stability of the IPN composites were studied systematically in terms of composition. Results revealed that the addition of HGB into polyurethane/epoxy IPN can significantly improve not only the tensile strength but also the impact strength. The tensile strength was increased by 61% and at the same time the impact strength was increased by 25% when the HGB content was 1.5%. The damping properties were better than the composition of 0.5% or 2% HGB content when the HGB content was 1% or 1.5%. The thermal decomposition temperature was also slightly improved by the incorporation of HGB. It is suggested that the HGB reinforced polyurethane/epoxy resin IPN composites could be used as structural damping materials.

Tribological Performances of Thermosetting Polyimide Matched with Steel and Ceramic

ABSTRACT The tribological properties of thermosetting polyimide (TPI) mated with Si3N4, Al2O3, and GCR15 balls are investigated from room temperature to 300°C. TPI mated with ceramic balls shows a lower coefficient of friction (COF) and wear rate (WR) at room temperature due to the lack of a transfer film on TPI–ceramic balls, which is demonstrated by energy-dispersive spectroscopy (EDS) and different wear mechanisms. A conclusion is drawn that a transfer film cannot form on ceramic balls due to the low chemical activities of ceramic materials, especially under higher load conditions. Under high temperatures, COFs of TPI–ceramic balls present a diverse trend compared to TPI–GCR15. Moreover, transfer films on ceramic balls begin to form as the temperature increases, which is easily determined by EDS of the tribological marks on ceramic balls. The differences presented above can mainly be ascribed to the diversities of different properties of mated balls.