Post about "composite"

Synthesis and Properties of the In-situ Surface-Modified Nano-SiO2/Nylon 1010 Composites

The PA1010-based nanocomposites containing different surface-modified nano-SiO2 were prepared by melt blending method and in-situ Polymerization. The nylon 6 /nano- SiO2 composites were prepared by in-situ polymerization. The mechanical properties of nanocomposites were investigated in detail. The mechanisms of reaction between the different surface-modified nano-SiO2 and the nylon matrix were presumed and discussed, and the subsequent dispersing behavior of silica in nylon matrix was also characterized. Furthermore, the microstructure, crystallization, melting behaviors as well as thermal stability of the composites prepared by melt blending were systematically studied. At the same time, the effect of diferent surface-modified nano-SiO2 on the structure and properties of composites was also elucidated. The main results are summarized as follows:1. For the nano- SiO2 /nylon1010 composites prepared by melt blending, the results of mechanical testing showed that the addition of reactable nano-SiO2 (RNS) could reinforce the tensile strength, impact strength,break elongation and Yong’s modulus of nanocomposites. It could improve the mechanical prorerties and had good effects on the reinforcement and toughening of the composites. The incorporation of dispersible nano-SiO2 (DNS) could increase the notched impact strength and break elongation of nanocomposites in the case of holding the Yong’s modulus of material; but it would produce a negative influence on the tensile property of nanocomposites. For composites prepared by in-situ polymerazition, the addition of nano-SiO2 (whether RNS or DNS) could enhance the toughness and stiffness of composites, but the change of material tensile strength was not obvious.2. In order to farther analyse more deeply the interaction between different surface-modified nano-SiO2 and PA1010 matrix during the preparation of nanocomposites, the extraction treatment of nanocomposites was used, and extraction products were investigated by Fourier-transform infrared spectroscopy. The results showed that there was a strong interaction at the interface of RNS and PA1010 matrix, which promoted the formation of interface structure based on hydrogen bonding and covalent bonding. The interfacial interaction of DNS and PA1010 matrix is not very strong, which was connected each other only by few hydrogen bonding and intertwist of chains segments. When mechanical properties of RNS / PA1010 and DNS / PA1010 nanocomposites are compared, it is found that different surface structure of nanoparticles would produce different influences on the mechanical properties of nanocomposites. In addition, based on the result of TGA the addition of nano-SiO2 could enhance the thermal stability of composites, but the effect of RNS on the thermal stability of material was more than that of DNS. The results showed that thermal properties of nanocomposites were closely correlated with the different surface structure of nano-SiO2.3. Melt and crystallization behavior of DNS / PA1010 and RNS / PA1010 nano-composites prepared by melt blending were also investigated. The results showed that the addition of DNS and RNS had the different effect on the melt and crystallization behavior of the composites. The addition of RNS increased the melt temperature and decreased the crystallization temperature of nanocomposites, promoted the crystallization of PA1010. At the same time the RNS increased the crystallinity of PA1010. While as a nucleating agent, DNS reduced the melt tempreature and increased the crystallization tempreature of composites. But it made the crystallinity of nanocomposites decreased a little. In the study of crystallization structure of nanocomposites, it was found that the addition of RNS and DNS did not change the crystal form of nylon 1010.4. The microstructure of nano-SiO2 / nylon1010 composites prepared by in-situ polymerization was characterized by scanning electron microscopy (SEM), X-ray Diffraction (XRD) and Differential scanning calorimetry (DSC). The results indicated that RNS and DNS could disperse rather well in nylon matrix. The addition of RNS and DNS changed the crystal form, hindered the formation of theγ-crystalline of nylon 1010. Nano-SiO2 made the melt temperature of nylon1010 increased 45 oC and the crystallization temperature increased 58 oC. These indicated that the filling of SiO2 acted as the heterogeneous nucleation spot of the crystallizing induced and made crystallizing process easier at higher temperature. At the same time, it is found that the effect of the nano-SiO2 added by in-situ polymerization on the melt and crystallization behavior of nylon1010 was much more than that of it added by melt blending.5. The MC PA6 / nano-SiO2 composites were prepared by in-situ polymerization and their properties were investigated. The results showed that nano-SiO2 had little influence on the polymerization ofε-caprolactam when the load of nano-SiO2 was low. The strong interaction between nano-silica and caprolactam/sodium- caprolactam (hydrogen bonds and chemical bonds) accelerated the homogeneous dispersion of silica in the medium. Sequentially, this strong interaction made the tensile and impact strength increased, which indicated that in-situ surface-modified nano-SiO2 not only could strengthen but also toughen the nylon matrix. The results of XRD indicated that both MC nylon 6 and its RNS and DNS nanocomposites showed a typicalαcrystalline form diffraction peak. This meaned nano-SiO2 did not change the crystal modality of nylon 6. The TGA results showed that nano-SiO2 increased thermal stability of composites and the effect of RNS was much more than that of DNS, which were closely correlated with the different surface structure of nano-SiO2.

Synthesis of Y/MCM-41 Composite and Its Application in HDS

In recent years,the problem of global environmental pollution has become a serious. matter of concern.This has resulted in stringent regulations aimed at reducing the sulfur content of diesel oil,which is a major source of SOx,in the atmosphere in many countries.A considerable effort toward HDS and aromatics reduction has been made worldwide. Nevertheless,deep hydrodearomatization and desulfurization of diesel is still a challenging task because diesel contains bulky aromatic and sulfur-containing compounds.In general, noble metals show higher HDS activity than conventional metals when they are supported on zeolites and mesoporous silicas.In this study,we have prepared Supports with different pore structure and acid sites,The HDS over these supported Pd catalysts showed different activity, sulfur tolerance and nitrogen tolerance.In chapter 3,Palladium on different MCM-41 mesoporous materials was prepared by impregnation method.The result of pyridine infrared spectroscopy(Py-IR)indicated that AI-MCM-41 possessed mainly Lewis acid sites and MY contained mainly Brosted acid sites, while Si-MCM-41 showed low acidity.The DBT HDS over these supported Pd catalysts predominately took the route of hydrogenation(HYD),and their activities decreased in the order:Pd/Al-MCM-41>Pd/MY(M)>Pd/Si-MCM-41.The HDS product distribution revealed that Pd/Al-MCM-41 exhibited high desulfurization and isomerization activities and low hydrocracking activity,whereas Pd/MY showed a high hydrocracking activity but a relatively low desulfurization activity and deactivated quickly.Difference in the HDS performances of Pd/Al-MCM-41 and Pd/MY can be attributed to the difference in the pore structures and acidic properties of Al-MCM-41 and MY(M).Secondly based on the thoughts in chapter 3,apore structure design was proposed for sulfur-tolerant catalysts used in the second stake for HDS.we prepared a composite zeolite, that is,Y overgrown with a layer of MCM-41,as well as reviewed the effect on synthetic conditions.The sample was characterized about molar composition acid strength and pore structure by various techniques.The composite possesses a mesopore system as well as a micropore structure.The composite was used as the support for Pd catalysts,their HDS activities decreased in the order:Pd/MY(CTAB)>Pd/MY(M)≈Pd/MY(CTAC)>Pd/MCM-41,.The pore structure and acidity of support are key points for the sulfur tolerance of noble metal catalyst for HDS.Since diameter of DBT is much lager than the diameter of micropore of HY,it is reasonable to assume that molecules are difficult to access metal clusters encased in the micropore of zeolite HY.These micropore confined metal clusters act as active sites for hydrogenation with smaller dimensions than the micropore,as well as a source providing spillover hydrogen to recover poisoned metal sites located in pores accessible to DBT and to facilitate the hydrogenation of the molecules adsorbed on the acid sites outside the micropore.

The Research on the Preparation of Carbon Foams and Their Composites

Carbon foams, which exhibit an interconnected structure and a large porosity made up of macrospores, are important in many areas of modern science and technology, including aerospace, heat exchanger, catalyst support and electrode material due to their remarkable properties, such as low density, high open-cell ratio, low coefficient of thermal expansion, resistance to corrosion, easy machining and other superior performances. Moreover, Composites with specific properties can be obtained via combination of carbon foam with other materials.In the present thesis, carbon foams were prepared using polyurethane foam as template and furfuryl alcohol (FA), polyimide acid (PAA) as well as asphaltene (AS) extracted from CLR as carbon precursors. The synthesis process involves the impregnation of the carbon resources, solidification and carbonization. The products were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The basic parameters, electric conductivity and antioxidant ability were also investigated. The results indicate that the as-prepared products which have low density and high porosity are made up of interconnected ligament composed by turbostraic carbon structure.The products are semiconducting materials and show good antioxidant ability. The structure and impregnation ability of the template is improved via the pretreatment by alkali solution, consequently the carbon foam with higher open porosity; carbonization yield as well as bulk density can be obtained. In order to expand the application of carbon foams, composites were also synthesized by adding Ni (NO32 and CNT into polyamide acid. This thesis not only enriches the category of materials for the preparation of carbon foams, but also makes valuable contributions to the research and application of carbon foams.

Study of Soy Protein Isolate-Silver Composite and Graft Copolymer by Atom Transfer Radical Polymerization

Soy protein isolate (SPI) is a kind of natural macromolecule rich in kinds of amino acids, and soy protein isolate based materials are expected to be environment-friendly, biodegradable and reproducible products. We focused on novel strategies to create soy protein isolate-silver nanoparticle composite and soy protein isolate-polymer hybridsA simple route for the synthesis of soy protein isolate-silver nanoparticle composite using soy protein isolate (SPI) has been proposed in this work(PART 1). Well defined size distribution of silver nanoparticles are obtained by the method of UV irradiation of an aqueous solution containing silver nitrate (AgNO3) and SPI in the absence of any reducing agents and protecting agents. The purified composite solution exhibit a yellow color, indicating the formation of silver nanoparticles. Transmission electronic microscopy (TEM) revealed that the silver nanoparticles were well dispersed with an average diameter about 13 nm, and X-ray diffraction (XRD) analysis of the freeze-dried powder of SPI-silver nanoparticle composite confirmed the formation of metallic silver. UV-Vis spectrum showed that the purified solution yielded the maximum absorbance at about 430 nm due to surface plasmon resonance of the silver nanoparticles. Infrared spectroscopy confirmed that the polypeptide backbone of SPI was not cleaved during the conjugation process and some active amino groups were oxidized. The formation of silver nanoparticles might be related with the reduction and photochemistry between SPI and UV light. The size and size distribution of the resulting silver nanoparticles were dependent on pH and UV irradiation time. SPI-Ag nanoparticle composite showed excellent antibacterial activity against two representative bacteria, Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative) in the presence of SPI. Apart from ecofriendliness and easy availability, this work will give us an alternate method to synthesize silver nanoparticles.In part 2 of this paper, we described the synthesis of poly(2-hydroxythyl methacrylate) grafted soy protein isolates(SPI-g-PHEMA) using ATRP. Poly(2-hydroxythyl methacrylate) (PHEMA) is one of most extensively studied biocompatible polymer, which has been used for applications such as contact lenses. The scheme of the work was that the soy protein isolate macroinitiator (SPI-Br) was synthesized first by reacting the active amino groups with 2-bromoisobutyryl bromide, and SPI-g-PHEMA was prepared by atom transfer radical polymerization of HEMA in aqueous solution.The soy protein isolate macroinitiator (SPI-Br) was prepared by condensation reaction of the active amino groups and 2-bromopropionyl bromide, and the resulting secondary bromide could be used as initiator for HEMA monomer in atom transfer radical polymerization. FTIR and 13C-NMR spectra confirmed the conversion from SPI sequence to SPI-Br.Atom transfer radical polymerization of 2-hydroxythyl methacrylate (HEMA) on SPI was carried out in aqueous solution using SPI-Br as initiator, copper chloride/bipyridine (CuCl/bpy) as catalyst. FTIR spectrum was used to characterize the successful polymerization of HEMA onto SPI globulin. The graft chain was cleaved from SPI-g-PHEMA by degradation of hydrochloric acid for purpose of the measurement of molecular weight of graft chain by GPC. The changes in the spectra of SPI, SPI-Br, SPI-g-PHEMA and grafted chain confirmed successive steps in the synthesis of SPI-g-PHEMA hybrids. A series of comparative experiments were taken with different reaction mediums(H2O, H2O/ n-propanol, n-propanol), and higher molecular weight result was gained in aqueous solution by atom transfer radical polymerization. The number average molecular weight was about 11.6×103 and a polydispersity was about 1.12, so the water medium system was chosen for further study. The molecule weight and the polydispersity of graft chain cleaved from SPI-g-PHEMA prepared via ATRP initiated by soy protein isolate macroinitiator was similar to those of PHEMA prepared by normal ATRP using 2-bromoisobutyryl bromide without SPI in solution under similar reaction conditions.The solution properties of SPI-g-PHEMA were characterized by UV and Fluorescent spectrophotometer. The results indicated that with increasing of pH value, the solubility of SPI and SPI-g-PHEMA increased, and the hydrophobicity decreased. The zeta-potential of SPI and SPI-g-PHEMA solutions were also studied by zeta-potentiometer. The static charges on the surface of SPI molecules increased clearly after graft modification. And the values of the zeta potential of SPI and SPI-g-PHEMA solutions decreased with the increase of pH values. The TEM images showed that the diameter of SPI-g-PHEMA was beyond that of SPI, and the morphologies between SPI and SPI-g-PHEMA were different.

Mechanical Analysis on the Impact Property of Composite Cylindrical Shell

The major work of this paper is developed on the research of laminated composite shellssubjected to axial impact loads. Through the quasi-static compression test, its cushion energyabsorbing property is investigated, and finite element method is applied to simulate the dynamicresponse process of laminated shells under the drop impact.In ChapterⅠ, the history and real-life meaning in this field are introduced. The presentresearch status of composite structure is summarized as well.In ChapterⅡ, theories about the cushion energy absorbing property of the composite shells areintroduced, which are about the formula derivations of composite tube’s dynamic responseprocess, analyses of the energy dissipating principle through experiment, and influence factorsof structure’s crashworthiness.In ChapterⅢ, the axial compression test of laminated shells is carried out, and its results areanalyzed emphatically. The effects of the ply methods and initiation mode on specific energyabsorption are investigated, as well as the contrast of three initiation modes including chamferstructure, cusp structure and fillet structure, which help to find a method to enhance the energyabsorbing property of this material.In ChapterⅣ, Ansys/LS-DYNA is introduced about its finite element method. With it, twomodels are employed to simulate laminated composite shells under the drop impact, and thecontrast is made between simulating results and experimental data.In ChapterⅤ, the whole paper is summarized and some conclusions are obtained. Then, fartherinvestigations in this field are prospected.

Surface Modification of Mesoporous Silica Platelets and Its Application

Recently,as an important functionalization method,surface modification has been a hotspot in the material research.Having been surface modified,the capability of the mesoporous materials will be improved,and it will come into the excellent fictionalization mesoporous materials.This paper is based on the usages in the different fields,through the way of mesoporous materials surface organic modification method to enhance the hydrophobicity of the mesoporous materials,and have further,research and discuss for the preparation and the character of the polymer/mesoporous silica platelet composite.Adopting the post-transplanting method,more than ten surface modifiers such asγ-Aminopropyl triethoxysilane,γ-Methacryloxypropyl trimethoxy silane,Silane coupling agent KH-792,Octadecyl-trimethoxysilane,Tetrabutyl titanate,stearic acid, xylitol,n-Octanol,Dodecanol and Hexadecanol have been grafted on the surface of the SBA-15 mesoporous Silica platelet,and also through the testing methods such as N2absorption-desorption、FT-IR、SEM、TEM、TG、DTA and elemental analysis to characterize the sample.The result indicates that after the surface modificating,the sample keep the uniform ordered mesoporous pore channel,and its hydrothermal stability and hydrophobicity have been improved.Especially,when modified by n-Octanol,the number of organic functional groups grafted on the surface of mesoporous is the most,and the hydrophobicity have the most obviously improve.The SBA-15 mesoporous Silica platelet,which has been surface modified by the n-Octanol,with polymer HDPF and PET together to carry through the composite prepared by melt blending.The preparation of the SBA-15 mesoporous Silica platelet /HDPE and SBA-15 mesoporous Silica platelet /PET composite,and tested the sample character by the methods of electronic universal testing machine,SEM and DSC.Knowing from the SEM photograph,the sample,which has been surface modified by the n-Octanol,disperses uniformly in the matrix HDPE,and has good compatibility.When it contains 3%SBA-15 meso-porous silicon wafer,the tensile strength of the composite material increases 47.75%,and the bending strength 7.9%.

Preparation and Catalytic Properties of TiC、WC Matrix Porous Carbide

In this paper,Ni3C-TiC、WC-TiC and SiC-WC composite was prepared by solid state sintering method in reduction atmosphere at 1560℃,phase exchange,crystal structure, oxidation resistance behavior,thermal expansion coefficient,mechanics performance,pore size distribution and microstructures were tested by X–ray diffraction(XRD),differential thermal analysis(DTA),thermal expansion device(TED),mechanics pressure machine, mercury intrusion porousimetry(MIP) and scanning electron microscope(SEM) instruments, the catalytic properties and catalytic mechanism of different composite carbide were discussed with the result of gas chromatography(GC) and gas chromatography-mass spectrometry(GC-MS).Result indicated that:In the Ni added porous composite TiC composite,Ni metal volatilized at high temperature,bonding the TiC matrix particles and transferred into Ni3C in reduction atmosphere;the radius of composite carbide particle was between 2μm and 10μm with “mushroom cloud” shape,pores uniform distributed,1~5μm;Oxidation resistance increased from 675K to 820K with 10wt%Ni added.Porous WC-TiC composite was synthesized with different WC precursor tungsten oxide and ammonium paratungstate.As tungsten oxide was precursor,the diameter of prepared WC was 1~5μm.Connected pores with wide pore size distribution,0.3~5μm,and low surface area, 2.976m2/g,were formed for the decomposition of ammonium bicarbonate.When oxide was replaced by APT,the final WC uniform distributed with the radius of 50~200nm,the pores were bimodal distributed,200~800nm and 2~5μm,as the synergistic effect of APT and ammonium bicarbonate,the surface area increased to 4.082 m2/g.In the SiC-WC composite,as the percentage of Si increases from 2 wt%to 14wt%in batches,the thermal expansion coefficients are from 4.11×10-6/K to 4.76×10-6/K,it got the lowest point 4.11×10-6/K when Si was 8wt%,the oxidation peak increased from 600K to 800K and their flexural strength decreased gradually,from 120MPa to 80MPa;The pore size distributions were unimodal(400nm,200~1000nm) and bimodal(700nm and 10μm, 400~1000nm and 5~20μm) without and with NH4HCO3 as a pore generating agent respectively. Porous nickel-titanium carbide composite was excellent catalyst for alcohol dehydration, the selectivity of ethylene was 98.41%at 380℃;the maximum alcohol velocity changed from 8ml/min to 200ml/min as temperature increased from 360℃to 500℃;among different concentration alcohol,75~99%,the conversion rate of reached maximum 98.4%at the alcohol concentration 95%,the selectivity increased gradually at the velocity of 50ml/min in 400℃.The selectivity of propylene first increased and then decreased as the temperature rises, it got the peak point 99.7%at 450℃;flow velocity of propanol did not had profound impact on selectivity when the flow velocity below 200ml/min,above 99%,but the selectivity decreased as the flow velocity surpassed 200ml/min.High surface area WC was novel catalyst for alkane isomerization.Tungsten carbide prepared by tungsten oxide had low surface area and bad catalytic properties,the selectivity of isopentane and pentane conversion rate at 350℃was 5.68%and 16.21%,respectively.The WC used APT as precursor with relative high surface area had high selectivity and conversion rate,12.91%and 48.44%at 350℃.The reaction was exothermic first order reaction;the calculated activation energy was 62.98kJ/mol with the reaction rate of different temperature.

Synthesis and Characterization of Organic/Inorganic Composites Based on Polyaniline

Silica nanopartices were modified by silane coupling agent containing aniline moieties. The grafting of N-substituted aniline on surfaces of silica nanoparticles were conducted through hydrolysis of triethoxysilylmethyl N-substituted aniline (ND-42) and the following condensation reaction with silanol groups on surfaces of SiO2. Chemical anchoring of modified silica nanoparticles onto polyaniline (PANI) chains was conducted through electro-co-polymerization of aniline and N-substituted aniline grafted on surfaces of silica nanoparticles, and the resulting composite film displayed nanofiborous morphologies (ca.50 nm in diameter). Electrochemical studies showed that both PANI/ND42-SiO2 and PANI/SiO2 which was synthesis by the electro-co-polymerization of aniline and unmodified silica nanoparticles, displayed typical redox peaks of PANI in 0.5 mol·L-1 H2SO4, while PANI/ND42-SiO2 showed weaker degradation peak, suggesting higher electrochemical stability. The capacitor performances of PANI/ND42-SiO2 and PANI/SiO2 were studied by chronopotentiometry. PANI/ND42-SiO2 exhibited an average specific capacitance of 380 F·g-1 at a current density of 2 mA-cm-2, ca.40% higher than that of PANI/SiO2. The hybrid film also showed improved cyclic stability.Composite material PANI/KIT-6, with PANI filling in the 3-D interconnected pore channels of mesoporous silica, KIT-6, has been synthesized via a gas phase method. The composite formation and the presence of PANI inside pore channels of KIT-6 were indicated by X-ray scatter (SAXS), transmission electron microscopy (TEM) and N2 sorption isotherm.. SAXS patterns showed that the bicontinuous cubic mesostructure was retained very well after incorporation of PANI in the channels. The TEM images of PANI/KIT-6 showed ordered mesoporous structure, but the pictures were smeared and dark. N2 sorption isotherms showed decrease of surface area, pore volume and pore diameter, and a narrow pore size distribution, indicating the uniform incorporation of PANI in the mesoporous channels. The presence of PANI in the composite material was evidenced by FT-IR spectrum. The morphology of KIT-6 and PANI/KIT-6 were observed by scan electron microscopy (SEM). The images showed that the morphology of PANI/KIT-6 was similar to that of KIT-6, indicating the confinement of PANI within KIT-6 channels instead of locating on the outer surface. The thermal properties of PANI/KIT-6 and bulk PANI prepared similarly were measured by thermogravimetric anylysis in air. The bulk PANI decomposed between 280 and 630℃(with DTG peak at 458℃), while the encapsulated polymer decomposed slowly from 280 to 630℃(with DTG peak at 458℃), indicating improved thermal stability upon composite formation.PANI was confined in mesoporous carbon, C-46, to afford PANI/C-46-1, PANI/C-46-2 and PANI/C-46-3 through oxidative polymerization of aniline adsorbed into the pore channel of C-46 previously by immerging the mesoporous carbon in ethanol solution of aniline (the ratio of aniline to ethanol was 1:29,2:28 and 4:26, v/v). The structures of the composites were characterized by X-ray diffraction (XRD), TEM and N2 adsorption isotherm. XRD patterns showed that the composites retained 2-D hexagonally mesostructure. TEM images of PANI/C-46-1 and PANI/C-46-2 showed large domains of highly ordered strip-like and hexagonally arranged images, while TEM images of PANI/C-46-3 were a bit blurry. N2 sorption isotherms of PANI/C-46-1 and PANI/C-46-2 showed decrease of surface areas, pore volumes and pore diameters with narrow pore size distributions, but these two composites still possessed opened pore channels. T-plot analysis showed that the micropore surface areas and micropore volumes of PANI/C-46-1 and PANI/C-46-2 also decreased. These result indicated that PANI distributed both on the pore surface and in the framework of C-46. However, N2 sorption isotherms of PANI/C-46-3 showed that the pore channels were blocked. The composites and bulk PANI prepared under similar condition were characterized by FT-IR. Compared with the bulk PANI, vibrations of PANI/C-46-1 and PANI/C-46-2 shifted to lower wavenumbers, while no absorption bands shift was observed for PANI/C-46-3. The morphology of C-46 and the composites were observed by SEM. Virtually no difference in surface morphology between the C-46 host and the composites was observed, excluding the possibility that PANI was on the outer surface of the host material.

Research on Control System and Head of 7-Axis NC Fiber Placement Machine

As a kind of composites, fiber reinforce plastic has lots of good characters, such as light weight, anticorrosion, anti-fatigue damage, few machining, absorbing microwaves of the radar etc. It is widely used in aeronautics and astronautics industry.NC fiber placement basing on the fiber winding, is a kind of manufacturing advanced automatic manufacturing technique. Fiber placement equipment controlled by the computer system, can complete the assignments of fiber placement on the mandrel’s surface following set locus. It can complete variable angle continuously placement, form concave curve surface, change the width of fiber belt. It also applies to manufacture the fiber reinforced product whose configuration is complex, such as the asymmetric revolving body with negative curvature, shell component with quirk or strengthening rib.According to the path of fiber placement, 7-aixs NC fiber placement machine should contain 3 translational degrees, 4 rotational degrees and the head. By improving the 6-axis winding equipment of CNC laboratory, reserved mainshaft C coordinate and three rectilinear X,Y,Z coordinates, added an wrist which has 3 rotational degrees. The head of fiber placement is controlled by the wrist and the machine tool. The head is the key device of the placement machine with complex structure. It places the fiber on the mandrel’s surface. In the head, the main function modules are clamping, restarting, cutting, compacting. The four modules ordered in line, independent, the passages of the fiber can increased by adding the modules. The cylinders and servomotor complete the task in each module.The control mode of the placement machine is IPC+UMAC+PLC, this is an Open CNC System for 7-aixs fiber placement machine. IPC takes charge of the NC program format, condition monitoring etc. UMAC takes charge of the machine motion control, PLC controls logic control. This CNC software using on the Windows XP system, was developed by VC6.0. It was designed as modular. There are three modular in the software, Information Hinting, Manual Operation, Automatic Operation, which developed by dynamic link library PComm32 in UMAC. Human-Machine Interface is simple operation, convenient maintenance.

The Preparation and Application of Starch/Rubber Composites

It is reported that corn starch, partly replaced carbon black(CB), will improve the tractive properties, hysteresis loss and reduce rolling resistance of tire, but the dispersion of starch in rubber matrix and the interfacial strength between starch and rubber matrix still requires improved. Latex compounding method (LCM), one of the most intelligent processing methods by now, is used to prepared starch/rubber composites. Modifier is also added to enhance interfacial strength between starch and rubber matrix. The effect of modify is studied through performance testing of composites.Prepared by LCM, starch/SBR composites are modified by ENR, VPL, LPB-g-MAH respectively. The results show that the mechanical properties of the material did not change significantly.Starch/SBR/CB composites prepared from Starch/SBR Blend by LCM, which blended with carbon black and respectively other modifier ENR, VPL, LPB-g-MAH, KH792, KH792/LPB-g-MAH and RF. The results showed that, RF modified composites shows marked improvement on the mechanical properties and storage modulus of vulcanized rubber, while the rolling resistance increased slightly and wear resistance is decreasing. However the wear-surface SEM photos show clearly that the interfacial strength is enhanced. When RF dosage is 1.2phr, the composits show the best comprehensive performance. By adding KH792 and glycerol respectively in RF modified starch/SBR/CB composites, RF/KH792 modified composites can be get, whoes curing process is influenced by KH792, which causing the mechanical properties and wet skid resistance decline, but reducing rolling resistance, and wear resistance improved slightly. Due to the glycerol, the mechanical properties of the composite as hardness, Elongation atbreak, tear strength reduced and vulcanizate tand at 60℃underintensive strain increased, but wet skid resistance and wear resistance decline.Compared with the composites prepard by directly compounding method(DCM), the LCM ones show greater mechanical properties and higher modulus. After mixing with carbon black to the two kinds of starch/NR blends, The performance testing of two starch/NR/CB composites shows that, composites prepared by LCM obtains lower rolling resistance, better wet skid resistance and wear resistance; and the glass transition shift at a lower temperature. Furthermore, modified by RF, the results show that the stress at 300%elongation, tensile strength has increased, wet skid resistance and wear resistance increased, rolling resistance has increased. Loading 1.8phr RF to modify composites gets relatively good properties. Based on that, using RF together with KH -792 to modified starch/NR/CB composites of which starch/NR is prepared by LCM. The result showes that the hardness of composites and tear strength decline, tensile strength slightly lower, elongation increase, permanent deformation significantly lower, wear resistance decrease, rolling resistance decreased significantly, and wet skid resistance increased.