2000 Vol. 17, No. 4
2000, 17(4): 1-5.
Abstract:
PZT powder is made using oxide one off sintering technique. Its X ray diffraction (XRD) peaks are monitored and shown to be in crystallization phase of pure square with Zr/Ti equal to 52:48. The pattern of the PZT powder is observed with SEM; the mold technique of PVDF is analyzed by TG DTA. Six sorts of PZT/PVDF composites are obtained with different PZT volume ratios by compression mould/sintering technique. Tests of dielectric and piezoelectric show that electric parameter accretion increases nonlinearly with PZT content, when the volume content of PZT exceeds 70%, dielectric constant ε and piezoelectric constant d33 increase rapidly, and when it reaches 90% the electric parameters are almost the same as the pure PZT's.
PZT powder is made using oxide one off sintering technique. Its X ray diffraction (XRD) peaks are monitored and shown to be in crystallization phase of pure square with Zr/Ti equal to 52:48. The pattern of the PZT powder is observed with SEM; the mold technique of PVDF is analyzed by TG DTA. Six sorts of PZT/PVDF composites are obtained with different PZT volume ratios by compression mould/sintering technique. Tests of dielectric and piezoelectric show that electric parameter accretion increases nonlinearly with PZT content, when the volume content of PZT exceeds 70%, dielectric constant ε and piezoelectric constant d33 increase rapidly, and when it reaches 90% the electric parameters are almost the same as the pure PZT's.
2000, 17(4): 6-10.
Abstract:
The paper reported the effects of short glass fiber(GF) content and injection pressure on the microstructures and mechanical properties of GF/PP composites.Experimental results showed that the tensile strength was improved, but the impact strength, break elongation and melt flow rate (MFR) decreased with increasing of glass fiber content in GF/PP composites.Orientation degree of GF in core layer was promoted with increase of injection pressure, but the orientation degree of GF in skin layer was parallel to the melt flow direction(MFD) by metallographic optical microscopy and SEM.The crystalizing ability of polypropylene in GF/PP composite went down with increase of GF content by polarization microscopy.
The paper reported the effects of short glass fiber(GF) content and injection pressure on the microstructures and mechanical properties of GF/PP composites.Experimental results showed that the tensile strength was improved, but the impact strength, break elongation and melt flow rate (MFR) decreased with increasing of glass fiber content in GF/PP composites.Orientation degree of GF in core layer was promoted with increase of injection pressure, but the orientation degree of GF in skin layer was parallel to the melt flow direction(MFD) by metallographic optical microscopy and SEM.The crystalizing ability of polypropylene in GF/PP composite went down with increase of GF content by polarization microscopy.
2000, 17(4): 11-14.
Abstract:
The isothermal cure behavior of epoxy-polyam ide and epoxy-polyam ide-glass m icroballsw ith varying composition w as investigated by the dynam ic torsional vibration method in four varioustemperatures. The gel time tg and apparent activation energy Ea of cure reaction w ere estimated. Theeffect of glass m icroball on gel time and apparent activation energy has been considered. The nonequilibrium thermodynam ic fluctuation theory can successfully describe and p redict the mechanicalproperties of the resin system w ith or w ithout glassm icroball during the curing p rocesses.
The isothermal cure behavior of epoxy-polyam ide and epoxy-polyam ide-glass m icroballsw ith varying composition w as investigated by the dynam ic torsional vibration method in four varioustemperatures. The gel time tg and apparent activation energy Ea of cure reaction w ere estimated. Theeffect of glass m icroball on gel time and apparent activation energy has been considered. The nonequilibrium thermodynam ic fluctuation theory can successfully describe and p redict the mechanicalproperties of the resin system w ith or w ithout glassm icroball during the curing p rocesses.
2000, 17(4): 15-19.
Abstract:
A new type of soluble PI/SiO2 nanocomposite was successfully prepared by sol gel process with the addition of small amounts of γ glycidyloxypropyltrimethoxysilane. Furthermore, the effects of coupling agent on the morphology and properties of the PI/SiO2 nanocomposite were investigated using UV vis, FT IR and SEM. The density and solubility of the PI/SiO2 nanocomposite were also measured. The results show that the coupling agent has great influence on the morphology of the PI/SiO2 nanocomposite.The size of SiO 2 inorganic particle becomes much smaller with the addition of coupling agent, which makes the PI/SiO2 films become transparent. Fortunately, the solubility of the PI/SiO2 nanocomposite is also improved by the coupling agent. And all these effects become even clearer with the amount of coupling agent. The density of the PI/SiO2 nanocomposite is also increased by coupling agent.
A new type of soluble PI/SiO2 nanocomposite was successfully prepared by sol gel process with the addition of small amounts of γ glycidyloxypropyltrimethoxysilane. Furthermore, the effects of coupling agent on the morphology and properties of the PI/SiO2 nanocomposite were investigated using UV vis, FT IR and SEM. The density and solubility of the PI/SiO2 nanocomposite were also measured. The results show that the coupling agent has great influence on the morphology of the PI/SiO2 nanocomposite.The size of SiO 2 inorganic particle becomes much smaller with the addition of coupling agent, which makes the PI/SiO2 films become transparent. Fortunately, the solubility of the PI/SiO2 nanocomposite is also improved by the coupling agent. And all these effects become even clearer with the amount of coupling agent. The density of the PI/SiO2 nanocomposite is also increased by coupling agent.
2000, 17(4): 20-25.
Abstract:
The thermal expanding behavior of carbon fiber/epoxy textile composites made from plane and 3 D braided structure was experimentally studied, including the thermal deformation and the coefficient of thermal expanding (CTE). The anisotropy of thermal response is analyzed and thermal expanding mechanisms are discussed by macro microscale mechanics. These results provide an important experimental basis for dimensional stability improvement and a zero expanding structure designing of precise instrument and space field.
The thermal expanding behavior of carbon fiber/epoxy textile composites made from plane and 3 D braided structure was experimentally studied, including the thermal deformation and the coefficient of thermal expanding (CTE). The anisotropy of thermal response is analyzed and thermal expanding mechanisms are discussed by macro microscale mechanics. These results provide an important experimental basis for dimensional stability improvement and a zero expanding structure designing of precise instrument and space field.
2000, 17(4): 26-31.
Abstract:
The structure transformations have been studied by X ray diffraction (XRD) and radial distribution function (RDF). Chemistry titration has been employed to determine residual B 2O3 content in the BN fibers. The results show that the boron nitride fibers mainly consisted of turbostrastic structure with some hexagonal phase and rhombohedral phase after nitriding at 1100℃, and the main crystallization phase in fibers was affirmed as rhombohedral phase after 1800℃ in nitrogen atmosphere.
The structure transformations have been studied by X ray diffraction (XRD) and radial distribution function (RDF). Chemistry titration has been employed to determine residual B 2O3 content in the BN fibers. The results show that the boron nitride fibers mainly consisted of turbostrastic structure with some hexagonal phase and rhombohedral phase after nitriding at 1100℃, and the main crystallization phase in fibers was affirmed as rhombohedral phase after 1800℃ in nitrogen atmosphere.
2000, 17(4): 32-37.
Abstract:
Three low viscosity benzoxzine resins were synthesized, and two kinds of RTM resins based on the benzoxazine resins containing catalyst of organic acid or epoxy tertiary amine and their glass cloth laminates were prepared. The influence of components and catalysts on viscosity and gelation time of the resins as well as the mechanical properties of the laminates has been investigated systematically. Both benzoxazine RTM resins catalyzed by organic acid or epoxy tertiary amine all have good technological properties; their viscosity is lower than 500cp in 2 hours at 70~90℃. The laminate made from organic acid system has T g 185℃(DMA) and flexural strength 405MPa at 180℃. The laminate made from epoxy tertiary amine system has T g 175℃ (DMA) and flexural strength 500MPa at 155℃. All the laminates can be used as heat resistant structural materials at 155℃.Therefore, a new heat resistant resin system required for RTM technological properties has been developed.
Three low viscosity benzoxzine resins were synthesized, and two kinds of RTM resins based on the benzoxazine resins containing catalyst of organic acid or epoxy tertiary amine and their glass cloth laminates were prepared. The influence of components and catalysts on viscosity and gelation time of the resins as well as the mechanical properties of the laminates has been investigated systematically. Both benzoxazine RTM resins catalyzed by organic acid or epoxy tertiary amine all have good technological properties; their viscosity is lower than 500cp in 2 hours at 70~90℃. The laminate made from organic acid system has T g 185℃(DMA) and flexural strength 405MPa at 180℃. The laminate made from epoxy tertiary amine system has T g 175℃ (DMA) and flexural strength 500MPa at 155℃. All the laminates can be used as heat resistant structural materials at 155℃.Therefore, a new heat resistant resin system required for RTM technological properties has been developed.
2000, 17(4): 38-42.
Abstract:
Epoxy resin could be oriented in magnetic field (MF) for its molecule structure having larger magnetic susceptibility anisotropy. It can maintain the orientation through crosslinking in magnetic field. This paper reviewed the orientation theory of polymer in MF and the influence of MF on the properties of epoxy resin and its composites.
Epoxy resin could be oriented in magnetic field (MF) for its molecule structure having larger magnetic susceptibility anisotropy. It can maintain the orientation through crosslinking in magnetic field. This paper reviewed the orientation theory of polymer in MF and the influence of MF on the properties of epoxy resin and its composites.
2000, 17(4): 43-47.
Abstract:
The goal of this paper is to study the short fiber reinforced composite used for manufacturing parts by the RPM (Rapid Prototyping/Part Manufacturing) process. In the experiment, the short glass fiber reinforced ABS composite is modified by adding a series of agents. The toughness and mechanical properties of the resultant composite filament from injection molding machine are improved so as to be used for FDM (Fused Deposition Manufacturing) process. The effect of the modification is evaluated from microcosmic aspect. The samples are made by modified short fiber reinforced ABS in the RPM equipment, and then the effect of the modification is analyzed.
The goal of this paper is to study the short fiber reinforced composite used for manufacturing parts by the RPM (Rapid Prototyping/Part Manufacturing) process. In the experiment, the short glass fiber reinforced ABS composite is modified by adding a series of agents. The toughness and mechanical properties of the resultant composite filament from injection molding machine are improved so as to be used for FDM (Fused Deposition Manufacturing) process. The effect of the modification is evaluated from microcosmic aspect. The samples are made by modified short fiber reinforced ABS in the RPM equipment, and then the effect of the modification is analyzed.
2000, 17(4): 48-53.
Abstract:
WT5,5”BZ]Polyimides have excellent thermal stability, outstanding mechanical and good dielectric performance. Recently, many new kinds of polyimides have been developed. The study and development of polyimides are summarized in this paper. Polyimides with unique properties can be achieved by introducing special structures. Carbon fiber/polyimide composites for application to aerospace possess some unique characteristics including resistance to high temperature, high specific modulus and high specific strength. Besides, the utilization of polyimides in microelectronic industry is included.
WT5,5”BZ]Polyimides have excellent thermal stability, outstanding mechanical and good dielectric performance. Recently, many new kinds of polyimides have been developed. The study and development of polyimides are summarized in this paper. Polyimides with unique properties can be achieved by introducing special structures. Carbon fiber/polyimide composites for application to aerospace possess some unique characteristics including resistance to high temperature, high specific modulus and high specific strength. Besides, the utilization of polyimides in microelectronic industry is included.
2000, 17(4): 54-57.
Abstract:
The effects of the different mixing techniques and filling components on the mechanical and frictional performance of PTFE composites are discussed in this paper. The results show that the comprehensive property of PTFE composite is considerable influenced by the different mixing methods, and that the changes of the amount and length of carbon fibers have obvious effects on the property of PTEF. Among them, when carbon fibers with length of 0.1mm are added to PTEF composites, it can obviously improve resistance to abrasion of PTEF.
The effects of the different mixing techniques and filling components on the mechanical and frictional performance of PTFE composites are discussed in this paper. The results show that the comprehensive property of PTFE composite is considerable influenced by the different mixing methods, and that the changes of the amount and length of carbon fibers have obvious effects on the property of PTEF. Among them, when carbon fibers with length of 0.1mm are added to PTEF composites, it can obviously improve resistance to abrasion of PTEF.
2000, 17(4): 58-62.
Abstract:
Effect of compression deformation at temperatures in the solid liquid two phase region on the microstructure and properties of SiCw/6061Al composites was investigated in the present study.It was found that the aspect ratio and orientation of whisker,densification and uniformity of composites,and interfacial bonding were affected more or less by compression deformation temperature.The properties of composites were affected by the changes of composite microstructure.The changes of composite properties after large deformation which took place at high temperatures were the most important index for evaluating high temperature plastic forming.The best compression deformation parameter was determined by analyzing the microstructure and the properties of composites.
Effect of compression deformation at temperatures in the solid liquid two phase region on the microstructure and properties of SiCw/6061Al composites was investigated in the present study.It was found that the aspect ratio and orientation of whisker,densification and uniformity of composites,and interfacial bonding were affected more or less by compression deformation temperature.The properties of composites were affected by the changes of composite microstructure.The changes of composite properties after large deformation which took place at high temperatures were the most important index for evaluating high temperature plastic forming.The best compression deformation parameter was determined by analyzing the microstructure and the properties of composites.
2000, 17(4): 63-65.
Abstract:
A SiC particle reinforced alum inum alloy metalmatrix composite, SiCP/6061A lMMC, is welded by laser beam w elding using nickel p lates as alloying fillermetal. M icrostructure of thew eld ischaracterized as functions of laser p rocessing parameters. Results show that the dissolution ofreinforcement SiC particles and formation of the needle-like harmful Al4C3 phases are noticeablysupp ressed using nickel as the alloying filler metal. The new reinforcements, such as Al3Ni, AlNi,etc, are p roduced in-situ in theweld by laser beam w elding of SiCP/6061AlMMC using nickel plate asalloying filler metal.
A SiC particle reinforced alum inum alloy metalmatrix composite, SiCP/6061A lMMC, is welded by laser beam w elding using nickel p lates as alloying fillermetal. M icrostructure of thew eld ischaracterized as functions of laser p rocessing parameters. Results show that the dissolution ofreinforcement SiC particles and formation of the needle-like harmful Al4C3 phases are noticeablysupp ressed using nickel as the alloying filler metal. The new reinforcements, such as Al3Ni, AlNi,etc, are p roduced in-situ in theweld by laser beam w elding of SiCP/6061AlMMC using nickel plate asalloying filler metal.
2000, 17(4): 66-70.
Abstract:
A new method of producing ceramic/metal functionally gradient material by electroless plating technique was proposed. The preparation of SiC/Ni P FGM was carried out by self made electroless plating facilities. The results show that the thickness of FGM coating and the gradient distribution of composition can be controlled by changing the parameters such as plating time, the addition speed and concentration of SiC particles after optimizing electroless plating technology. The good corresponding relationships among the SiC content, the microstructure and the mechanical property of the FGM are obtained.
A new method of producing ceramic/metal functionally gradient material by electroless plating technique was proposed. The preparation of SiC/Ni P FGM was carried out by self made electroless plating facilities. The results show that the thickness of FGM coating and the gradient distribution of composition can be controlled by changing the parameters such as plating time, the addition speed and concentration of SiC particles after optimizing electroless plating technology. The good corresponding relationships among the SiC content, the microstructure and the mechanical property of the FGM are obtained.
2000, 17(4): 71-75.
Abstract:
Two kinds of monodispersed SiO2 TiO2 composite particles with the uniform diameter of 18 nanometers and 40 nanometers separately were prepared by sol technology,and the best synthesis condition was also determined. Electron microscope revealed that the hydrated TiO 2 particle had been grafted onto the surface of SiO 2 particle, growing outside in a needle shape. Study on the covering process,the calcination behavior of the composite ultrafine powder and the surface modification displayed that the crystal form of TiO 2 transformed from anatase to rutile at 1100℃~1200℃, the o tridymite form of SiO 2 came into being in the same condition and the SiO2 TiO2 ultrafine powder modified by methanol could be redispersed well in ethanol.
Two kinds of monodispersed SiO2 TiO2 composite particles with the uniform diameter of 18 nanometers and 40 nanometers separately were prepared by sol technology,and the best synthesis condition was also determined. Electron microscope revealed that the hydrated TiO 2 particle had been grafted onto the surface of SiO 2 particle, growing outside in a needle shape. Study on the covering process,the calcination behavior of the composite ultrafine powder and the surface modification displayed that the crystal form of TiO 2 transformed from anatase to rutile at 1100℃~1200℃, the o tridymite form of SiO 2 came into being in the same condition and the SiO2 TiO2 ultrafine powder modified by methanol could be redispersed well in ethanol.
2000, 17(4): 76-79.
Abstract:
The sintered Si3N4 toughened by ZrO2(Y2O3) was prepared at high temperature (1400℃) and ultra high pressure (4.2GPa). The phase structure and the mechanical properties were investigated by XRD and the measurements of compressive strength and micro hardness. The results show that the sintered Si3N4 was toughened by Y2O3 partially stabilized ZrO2 with Al addition.The phase transformation and toughness were increased with Y2O3 content in less than 2.5mol% Y2O3.The toughness increasing came from t m transformation and micro cracks. Almost 100% t ZrO2 were retained in more than 2.5mol% Y2O3 but the toughening effect was weakened by less transformation. The hardness was increased with Y2O3 content because Y2O3 can promote Si3N4 sintered as liquid at high temperature.
The sintered Si3N4 toughened by ZrO2(Y2O3) was prepared at high temperature (1400℃) and ultra high pressure (4.2GPa). The phase structure and the mechanical properties were investigated by XRD and the measurements of compressive strength and micro hardness. The results show that the sintered Si3N4 was toughened by Y2O3 partially stabilized ZrO2 with Al addition.The phase transformation and toughness were increased with Y2O3 content in less than 2.5mol% Y2O3.The toughness increasing came from t m transformation and micro cracks. Almost 100% t ZrO2 were retained in more than 2.5mol% Y2O3 but the toughening effect was weakened by less transformation. The hardness was increased with Y2O3 content because Y2O3 can promote Si3N4 sintered as liquid at high temperature.
2000, 17(4): 80-83.
Abstract:
The effect of adding nano γ-Al2O3 powder on the sintering characteristics and microstructure of alumina and silicon carbide fibers was investigated. The results showed that the nano γ-Al2O3 powder was stuffed into the pores formed from the packing of micron alumina powder when its fiber was extruded. The density of the green alumina fiber increased with addition of nano γ-Al2O3 powder. The maximum density of the green fiber was obtained when γ-Al2O3 content is approximately 40%. Nano γ-Al2O3 powder, can promote the sintering of alumina and silicon carbide fibers, and a lower sintering temperature and higher fiber density may be expected.
The effect of adding nano γ-Al2O3 powder on the sintering characteristics and microstructure of alumina and silicon carbide fibers was investigated. The results showed that the nano γ-Al2O3 powder was stuffed into the pores formed from the packing of micron alumina powder when its fiber was extruded. The density of the green alumina fiber increased with addition of nano γ-Al2O3 powder. The maximum density of the green fiber was obtained when γ-Al2O3 content is approximately 40%. Nano γ-Al2O3 powder, can promote the sintering of alumina and silicon carbide fibers, and a lower sintering temperature and higher fiber density may be expected.
2000, 17(4): 84-87.
Abstract:
TCVI (Thermal Gradient CVI) process is a very potential process for C/C composite, by which C/C products with well distributed density can be manufactured in relatively shorter time. In this paper, the dynamic model and geometrical model of the process were established on the basis of theory of heat and mass transfer and structure character of the preform. According to these models, the technology of numerical simulation is applied to simulate and analyze the process. It's indicated by simulation that the preform is densified from interior to exterior during TCVI process so the external pores in the preform will not be sealed too early. The density homogeneity and the speed of deposition can be greatly improved by properly altering the thermal gradient in the preform. The result of simulation can lay the theoretical foundation for the development and application of TCVI process.
TCVI (Thermal Gradient CVI) process is a very potential process for C/C composite, by which C/C products with well distributed density can be manufactured in relatively shorter time. In this paper, the dynamic model and geometrical model of the process were established on the basis of theory of heat and mass transfer and structure character of the preform. According to these models, the technology of numerical simulation is applied to simulate and analyze the process. It's indicated by simulation that the preform is densified from interior to exterior during TCVI process so the external pores in the preform will not be sealed too early. The density homogeneity and the speed of deposition can be greatly improved by properly altering the thermal gradient in the preform. The result of simulation can lay the theoretical foundation for the development and application of TCVI process.
2000, 17(4): 88-91.
Abstract:
The paper presents a finite element model for strength analyses of a rotational composite shell under axial compression and internal pressure. Characteristics of stress distribution and locations and loads of failure are determined according to the model. The model is also developed to calculate stability of the shell under axial compression, external pressure and the combination of axial compression and external pressure. Experiments are completed for studying the strength of the shell under axial compression and internal pressure and the stability of the shell under the combination of axial compression and external pressure.
The paper presents a finite element model for strength analyses of a rotational composite shell under axial compression and internal pressure. Characteristics of stress distribution and locations and loads of failure are determined according to the model. The model is also developed to calculate stability of the shell under axial compression, external pressure and the combination of axial compression and external pressure. Experiments are completed for studying the strength of the shell under axial compression and internal pressure and the stability of the shell under the combination of axial compression and external pressure.
2000, 17(4): 92-99.
Abstract:
It is a complex process for curing composite laminates and we need to research the principles of the curing process of composite in order to effectively design the operation technology of producing composite. In this paper, two models about curing process are set forth and developed. Then a computer code based on the models is made to calculate the curing process and optimize the operation technology of curing process of composite in order to ensure the quality of composite.
It is a complex process for curing composite laminates and we need to research the principles of the curing process of composite in order to effectively design the operation technology of producing composite. In this paper, two models about curing process are set forth and developed. Then a computer code based on the models is made to calculate the curing process and optimize the operation technology of curing process of composite in order to ensure the quality of composite.
2000, 17(4): 100-104.
Abstract:
Based on the fundamental equations of three dimensional elasticity, and by introducing boundary displacement functions, the state equation is established for thick laminated open cylindrical shell with clamped edges subjected to arbitrary loads. An analytical static solution is presented which is suitable for any thickness to span ratios. Because all the physical quantities appearing in the state equation are just the compatible quantities at the interfaces, the present paper is extremely convenient for solving the laminates. The solution given satisfies all the boundary conditions and continuity conditions between plies. In addition, the distributions of the boundary displacements along x or θ direction are assumed by polynomial functions, the convergence of the present method is faster and the stresses are continuous nearby the boundary.
Based on the fundamental equations of three dimensional elasticity, and by introducing boundary displacement functions, the state equation is established for thick laminated open cylindrical shell with clamped edges subjected to arbitrary loads. An analytical static solution is presented which is suitable for any thickness to span ratios. Because all the physical quantities appearing in the state equation are just the compatible quantities at the interfaces, the present paper is extremely convenient for solving the laminates. The solution given satisfies all the boundary conditions and continuity conditions between plies. In addition, the distributions of the boundary displacements along x or θ direction are assumed by polynomial functions, the convergence of the present method is faster and the stresses are continuous nearby the boundary.
2000, 17(4): 105-109.
Abstract:
A 4 node plate element based on Mindlin first order shearing theory is presented to analyze delamination front contact effect on pre buckling and post buckling behavior of composite laminates with elliptical delamination damage. Contact effect is analyzed by using gap element in the delamination region without friction being considered. The results show that delamination front contact effect is related to the aspect of elliptical delamination. Pre buckling and post buckling behaviors of composite laminates with delamination of which the major axis is consistent with the compressive load direction are affected significantly by the delamination front contact effect.
A 4 node plate element based on Mindlin first order shearing theory is presented to analyze delamination front contact effect on pre buckling and post buckling behavior of composite laminates with elliptical delamination damage. Contact effect is analyzed by using gap element in the delamination region without friction being considered. The results show that delamination front contact effect is related to the aspect of elliptical delamination. Pre buckling and post buckling behaviors of composite laminates with delamination of which the major axis is consistent with the compressive load direction are affected significantly by the delamination front contact effect.
2000, 17(4): 110-114.
Abstract:
A two dimensional elastic foundation to analyze the buckling of composite sandwich plates containing delamination between two faceplate laminates is established. By employing Rayleigh Ritz method, this paper studies the hygrothermal effect on buckling character of composite sandwich plates containing delamination between two faceplate laminates. The elastic coefficients and the hygrothermal coefficients of the composite faceplate laminate are dependent on temperature.
A two dimensional elastic foundation to analyze the buckling of composite sandwich plates containing delamination between two faceplate laminates is established. By employing Rayleigh Ritz method, this paper studies the hygrothermal effect on buckling character of composite sandwich plates containing delamination between two faceplate laminates. The elastic coefficients and the hygrothermal coefficients of the composite faceplate laminate are dependent on temperature.
2000, 17(4): 114-118.
Abstract:
The mechanical properties of poly(DL lactide)/hydroxyapatite composites was improved by treating the surface of hydroxyapatite reinforcing particles with silane agent(A 174). SEM observation indicated that the surface modified HA microparticles were uniformly distributed within PDLLA matrix, and showed a more intimate contact with the polymer matrix than that in the case of unmodified filler particles. XPS proved the presence of O P Si bond between the interfacial bonding by using such method, and a new biodegradable bone bonding composite can be made.
The mechanical properties of poly(DL lactide)/hydroxyapatite composites was improved by treating the surface of hydroxyapatite reinforcing particles with silane agent(A 174). SEM observation indicated that the surface modified HA microparticles were uniformly distributed within PDLLA matrix, and showed a more intimate contact with the polymer matrix than that in the case of unmodified filler particles. XPS proved the presence of O P Si bond between the interfacial bonding by using such method, and a new biodegradable bone bonding composite can be made.
2000, 17(4): 119-123.
Abstract:
Iron/polyacrylate composite particles were synthesized through inversed emulsion polymerization technique. The particles were then dispersed in silicone oil containing different additives to form electro and magneto rheological(ER and MR) fluids. Studying the influence of the additive on electro and magneto rheological effects, reveals that the fluid exhibits strong MR effects which do not change obviously with the type and amount of the additive, such as Span 80, MOA 3 and KH 550, while ER effects of the fluid change remarkably and differently in the same condition. The ER effect of the fluid decreases with increasing Span 80 content, while as for KH 550 it decreases in a much smaller degree. MOA 3 increases and then decreases the ER effect, leading to a maximum excess shear stress at the content of 1%~2%. This ER and MR effect difference stems from the different mechanism of the particle polarization and the interaction between the polarized particles under the electric and magnetic field.
Iron/polyacrylate composite particles were synthesized through inversed emulsion polymerization technique. The particles were then dispersed in silicone oil containing different additives to form electro and magneto rheological(ER and MR) fluids. Studying the influence of the additive on electro and magneto rheological effects, reveals that the fluid exhibits strong MR effects which do not change obviously with the type and amount of the additive, such as Span 80, MOA 3 and KH 550, while ER effects of the fluid change remarkably and differently in the same condition. The ER effect of the fluid decreases with increasing Span 80 content, while as for KH 550 it decreases in a much smaller degree. MOA 3 increases and then decreases the ER effect, leading to a maximum excess shear stress at the content of 1%~2%. This ER and MR effect difference stems from the different mechanism of the particle polarization and the interaction between the polarized particles under the electric and magnetic field.
2000, 17(4): 124-126.
Abstract:
The parameters of interfacial structure in EPDM/Al(OH)3 composites were studied with dynamic mechanical analyzer(DMA). A new method of estimating the interfacial layer thickness of composites with DMA was put forward. The effects of surface state of Al(OH)3 particles on the parameters of interfacial structure in EPDM/Al(OH)3 composites were discussed.
The parameters of interfacial structure in EPDM/Al(OH)3 composites were studied with dynamic mechanical analyzer(DMA). A new method of estimating the interfacial layer thickness of composites with DMA was put forward. The effects of surface state of Al(OH)3 particles on the parameters of interfacial structure in EPDM/Al(OH)3 composites were discussed.
