Development of organic inorganic composites by sol gel method for tooling materials

DEVELOPMENT OF ORGANIC/INORGANIC COMPOSITES BY SOL GEL METHOD FOR TOOLING MATERIALS LIU FENGMIN NATIONAL UNIVERSITY OF SINGAPORE 2006 DEVELOPMENT OF ORGANIC/INORGANIC COMPOSITES BY SOL GEL METHOD FOR TOOLING MATERIALS LIU FENGMIN (B Eng., Beijing University of Aeronautics & Astronautics) A THESIS SUBMITTED FOR THE DEGREE OF MASTER OF ENGINEERING DEPARTMENT OF MECHANICAL ENGINEERING NATIONAL UNIVERSITY OF SINGAPORE 2006 ACKNOWLEDGEMENT As a milestone, the thesis is by far one of the achievements in my life It is not only the result from my research work but also the painstaking efforts of many people who supported me and had faith in me in the past It could not even be dreamed without the elaborate guidance from Professors Jerry Fuh Ying Hsi, Wong Yoke San, and Lu Li who were my supervisors in the National University of Singapore I have being greatly benefited from both their deep insights and devoted spirits in science The thoughts they have offered have enriched my thesis a lot The things I have learned from them are never just only the sense of research but the mission for ‘never give-up’ and many others I am greatly indebted to my former supervisors, Professor Zeng Hua Chun in NUS and Dr Bart Follink who moved to CSIRO, Australia now, for encouraging me to pursue an academic career Their encouragements are definitely the root for the success I achieved today It is impossible to forget every single helping hand hidden behind my success I would like to express my gratitude to Dr Li Dongfei, Mr Huang Zhaohong, and Dr Zeng Xianting for their valuable contributions, discussions, and encouragements without that my thesis would never be so fruitful Last but not least, I am grateful to all of my colleagues at the Singapore Institute of Manufacturing Technology, CEL Coatings Industries Pte Ltd, and the Department of Mechanical Engineering (NUS) for their supports Especially I am indebted to Dr i Sandor Nemeth, Dr Tan Su Nee, Dr Andrew Soutar, Dr Zhao Luping, Dr Qi Guojun, Dr Marcel Bohmer, Mr Peter Cheong, Ms Xie Hong, Ms Liu Yuchan, Ms Ng Fern Lan, Mr Raymond Ong, Mr Aw Paw Kun, Mr Tan Boon Hee, Dr Chang Soo Kong, Dr Chen Quan, Ms Hu Qiujun, Mr Shu Geok Haw, Ms Pauline Shu, and many others I would like to thank my wife Sun Rui and my daughter Aofei for their understandings and loves during the past few years The support and encouragement from my family were in the end what made my thesis possible ii TABLE OF CONTENTS ACKNOWLEDGEMENT i TABLE OF CONTENTS iii SUMMARY vii LIST OF TABLES ix LIST OF FIGURES x LIST OF SYMBOLS xiv CHAPTER INTRODUCTION CHAPTER LITERATURE REVIEW 2.1 Sol Gel Synthesis 2.1.1 Sol Gel Chemistry 2.1.1.1 Hydrolysis and Condensation 2.1.1.2 Gelation 2.1.1.3 Modified Precursors 2.1.1.4 Effect of Process Parameters on Hydrolysis and Condensation 11 2.1.2 Aging of Gels 13 2.1.3 Drying of Gels 15 2.1.3.1 Stages of Drying 15 2.1.3.2 Routes to Avoid Cracking 18 2.1.4 Thermal Treatment 21 2.2 23 Sol Gel Applications 2.2.1 Thin Films and Coatings 24 iii 2.2.2 Monoliths 25 2.2.3 Powders, Grains, and Spheres 26 2.2.4 Fibers 27 2.2.5 Porous Gels and Membranes 27 2.2.6 Composites and Tooling Materials 28 2.2.6.1 Inorganic/inorganic Composites 28 2.2.6.2 Organic/inorganic Composites 29 CHAPTER PREPARATION OF SOL GEL MATRIX SYSTEM 33 3.1 Introduction 33 3.2 Experimental Procedure 34 3.2.1 Reaction Scheme 36 3.2.2 Structure Modeling 37 3.3 Results and Discussions 39 3.3.1 Determination of Hydrolysis Time 39 3.3.2 Determination of Removal Ratio of Methanol 40 3.3.3 Effect of Drying Environment 42 3.3.4 Determination of Molar Ratio of DMDS/MTMS 43 3.4 Summary 45 CHAPTER DEVELOPMENT OF CERAMIC-FILLED 47 ORGANIC/INORGANIC COMPOSITES 4.1 Introduction 47 4.2 Experimental Procedure 47 4.2.1 Materials 47 iv 4.2.2 The Route to Prepare the Composites 49 4.3 51 Results and discussion 4.3.1 Microstructure of Different Ceramic-filled Organic/inorganic 52 Composites 4.3.2 Comparison of Mechanical Properties between Different Ceramic-filled 56 Composites 4.3.3 Effects of Dispersion Time on Microstructures and Mechanical 57 Properties of Silica-filled Organic/inorganic Composites 4.3.4 Thermal Properties of Ceramic-filled Organic/inorganic Composites 60 4.3.4.1 Thermal Stability 60 4.3.4.2 Thermal Conductivity 62 4.4 62 Summary CHAPTER DEVELOPMENT OF METAL-FILLED 64 ORGANIC/INORGANIC COMPOSITES 5.1 Introduction 64 5.2 Experimental Procedure 64 5.2.1 Materials 64 5.2.2 The Route to Prepare the Composites 64 5.3 68 Results and Discussion 5.3.1 Comparison of Microstructure and Mechanical Properties between 68 Different Metal-filled Composites 5.3.2 Effects of Incorporation Two Metallic Fillers into the Composites on 71 Microstructure and Mechanical Properties 5.3.3 Thermal Properties of Metal-filled Organic/inorganic Composites 74 v 5.3.4 Electroless Nickel Plating on Stainless-steel-filled Organic/inorganic 76 Composites 5.4 Summary 77 CHAPTER CONCLUSIONS AND RECOMMENDATIONS 79 6.1 Conclusions 79 6.2 Recommendations 80 REFERENCES 81 vi SUMMARY Sol gel technology has been widely applied in industry as it offers a number of important advantages such as low temperature and mild reaction conditions, ability to produce castable, flexible materials when precursors containing organic groups are employed Fillers are also easily incorporated into the flexible matrix, which makes the method interesting for producing materials to specific applications Organic/inorganic composites prepared by the sol gel method are mostly used as coatings for different purposes, while a few of them are used to prepare bulk materials for waveguide and micro-electro-mechanical-system (MEMS) applications to produce ceramic microcomponents Sol gel composites have recently been exploited for tooling applications, but few research works are reported In this project, crack-free and castable organic/inorganic composites filled by ceramics or stainless steel particles have been developed, which offer a very high resistance against thermal degradation below 400oC and moderate mechanical properties Incorporation of metallic fillers to organic/inorganic sol gel matrix is a new approach to prepare sol gel composite Electroless nickel (EN) layer has been successfully deposited on the stainless steel filled composites with perfect adhesion between the EN layer and the composite The composites prepared by the above method might be a good candidate for tooling materials This research work started from preparation of organic/inorganic sol gel matrix system A combined sol-gel precursor of methyltrimethoxysilane (MTMS) and dimethyldimethoxysilane (DMDS) was used for the sol gel system A flexible and crack-free sol gel matrix system was prepared by the combined precursor at a molar ratio of vii DMDS/MTMD 0.175 in the sol gel matrix The cracking of gels occurs when the molar ratio is less than 0.15 or more than 0.1875 Careful aging and drying in a covered dish must be carried out to prevent warping of gels Following this, ceramic fillers such as silica, silicon carbide were incorporated into the organic/inorganic sol gel matrix The optimized volume fraction of the ceramic fillers in the composites is 30%, with moderate mechanical and thermal properties Different metallic fillers were incorporated into the sol gel matrix Composites filled with a combination of irregularly and sphere-shaped stainless steel particles of different size achieved both moderate mechanical strength and surface roughness Re-filling of the cured composite with the sol gel solution improved its microstructure and increased the mechanical strength significantly The organic/inorganic composites filled by both ceramics and stainless steel particles are thermally stable up to 400oC The thermal conductivity for stainless-steel-filled composites is 1.1 W/mK which is higher than that for silica-filled composites (0.455W/mK) viii stress of 11.4 MPa is achieved at the ratio of 30/30, while the highest maximum compression stress of 22.5 MPa is obtained at the ratio of SS420/SS42C of 15/45 This means that the mechanical properties depend less on the ratio of the combined metallic fillers when the ratio of SS420/SS42C is in the range of 15/45 to 45/15, which is in agreement with the SEM micrographs of the fracture surfaces Table 5-2 shows the roughness of cast composite surface prepared by different ratio of SS420/SS42C With increasing the SS420 content in the combined metallic fillers, the surface roughness is significantly improved compared with the single SS42C-filled composites When the ratio of SS420/SS42C is 30/30, the surface roughness reaches Ra 4.0 um while the roughness of single filler (SS42C) is Ra 10 um as stated in the previous section This is attributed to the incorporation of smaller sized and sphere shaped stainless steel filler SS420 5.3.3 Thermal Properties of Metal-filled Inorganic/organic Composites Fig 5-9 shows the thermogravimetric analysis results for different metal-filled organic/inorganic composites The composites filled by different metals show a very stable thermal property up to 400oC with a negligible change of 0.02% The sudden weight loses occurs at 625oC for the composites, which is consistent to the ceramicfilled composites stated in chapter This is caused by structure change which is explained in the previous chapter 74 Fig 5-10 shows the results of thermal conductivities of different metal-filled organic/inorganic composites The thermal conductivity for the stainless steel filled 75 composites is in a range of 1.0 to 1.1 W/mK which is double of the conductivity of ceramic filled composites, while the conductivity of high nickel content alloy (In-625) filled composite is much lower (0.6 W/mK) This might be due to the lower thermal conductivity of high nickel content steel compared with stainless steel 5.3.4 Elctroless Nickel Plating on Stainless Steel Filled Composites An electroless nickel (EN) layer with thickness of 50 microns is deposited on the surfaces of stainless steel filled composites Fig 5-11 shows SEM micrograph of cross-sectioned EN layer on the combined metal filler (SS420/SS42C ratio, 30/30)filled composite Perfect adhesion between the EN layer and the substrate is obtained, which is attributed to the connection of the EN layer and the stainless fillers shown in Fig 5-11 Images of EN plated final products (44 x 44 x mm) of the experiments are shown in Fig 5-12 The product a was made by combined metal (SS420/SS42C = 30/30)-filled 76 composites while product b was prepared with single SS42C filled composite, which shows a rougher surface than the former one, shown in Fig 5-12 5.4 Summary Crack-free and castable organic/inorganic composites filled by single metallic filler or combined stainless steel fillers were developed Incorporation of a combination of differently sized and shaped metallic fillers into the organic/inorganic sol gel system achieved moderate mechanical properties and surface roughness of the cast surface The optimized combination ratio of stainless steel filler SS420/SS42C is 30/30 Refilling the cured composite with the sol gel solution improved its microstructure and increased the mechanical properties significantly The best maximum flexural stress and compression stress for the composites filled by the optimized combination fillers are 11.4 MPa and 20.7 MPa respectively The organic/inorganic composites filled by 77 metals are also thermally stable up to 400oC The thermal conductivity for stainlesssteel-filled composites is only 1.1 W/mK 78 CHAPTER 6: CONCLUSIONS AND RECOMMENDATIONS 6.1 Conclusions A flexible and crack-free sol gel matrix system can be prepared by combined precursor of MTMS and DMDS The optimized molar ratio of DMDS/MTMS in the sol gel matrix is 0.175 The cracking of gels occurs when the molar ratio is less than 0.15 or more than 0.1875 Careful aging and drying must be carried out in a covered dish to prevent warping of gels The process is slow, lasting at least weeks Ceramic-filled organic/inorganic composites can be obtained by incorporating silica or SiC into the MTMS/DMDS sol gel matrix The optimized volume fraction of the ceramic fillers in the composites is 30%, with moderate mechanical and thermal properties The organic/inorganic composites show a very high resistance against thermal degradation below 400oC The thermal conductivity of composites filled by 30%vol of silica is only 0.455 W/mK Stainless steel particle filled organic/inorganic composites can be prepared A combination of irregularly shaped and sphere-shaped stainless steel particle filled composites can achieve moderate mechanical strength and surface roughness of the cast surface of the composites Re-filling of the cured composite with the sol gel solution to improves its microstructure and increased the mechanical properties significantly 79 The organic/inorganic composites filled by metallic particles are also thermally stable up to 400oC The thermal conductivity for stainless-steel-filled composites is 1.1 W/mK Electroless nickel layer can be deposited onto the stainless-steel-filled organic/inorganic composites with good adhesion 6.2 Recommendation To shorten the process time and meet the rapid tooling applications, freezegelation or freeze-casting techniques (Statham et al., 1998, Wei et al., 1996) can be applied to the preparation of the tooling materials by sol gel method Although the gel will be more porous compared with the composites obtained by current process, it might be compensated by re-filling with sol gel solution or colloidal sol The cost of the process will be higher than the current process To overcome the cracking or separation between the metallic fillers and the sol gel matrix which occurs in the current process, surface modification of the metallic fillers by a proper sol gel precursor or a colloidal sol can be tried before incorporating them into the sol gel matrix This may enhance the cohesive affinity between the fillers and sol gel matrix Due to time limitation, it was not tried in the project Further studies on the adequacy of properties and characteristics of composites prepared by sol gel method for tooling applications are needed This will involve producing a cast tool or a convert tool and testing its performances 80 References: Adachi, T and S Sakka The Role of N,N-Dimethylformamide, a Dcca, in the Formation of Silica-Gel Monoliths by Sol-Gel Method, J Non-Cryst Solids, 99, pp.118-128 1988 Ahmad, Z., M I Sarwar, S Wang and J E Mark Preparation and Properties of Hybrid Organic-Inorganic Composites Prepared from Poly(phenylene terephthalamide) and Titania, Polymer, 38, pp.4523-4529 1997 Aparicio, M and A Duran Hybrid Organic/Inorganic Sol-Gel Materials for Proton Conducting Membranes, J Sol-Gel Sci Technol., 31, pp.103-107 2004 Arkhireeva, A., J N Hay, J M Lane, M Manzano, H Masters, W Oware and S J Shaw Synthesis of Organic-Inorganic Hybrid Particles by Sol-Gel Chemistry, J SolGel Sci Technol., 31, pp.31-36 2004 Artaki, I., T W Zerda and J Jonas Solvent Effects on the Condensation Stage of the Sol-Gel Process, 81, pp.381-395 1986 Atkinson, D Rapid Prototyping and Tooling pp 52-70 Welwyn Garden City, Herts: Strategy Publications 1968 Bauer, W., H.-J Ritzhaupt-Kleissl and J H Hausselt Slip Casting of Ceramic Microcomponents, Microsystem Technologies, 4, pp.125-127 1998 Bernards, T N M Silicate Sol-Gel Chemistry as Studied by Hydrolysis-Gelation Time Curves PhD Thesis, Utrecht University 1997 Boonstra, A H., T N M Bernards and J J T Smits The Effect of Formamide on Silica Sol-Gel Processes, J Non-Cryst Solids, 109, pp.141-152 1989 Bounor-Legare, V., C Angelloz, P Blanc, P Cassagnau and A Michel A New Route for Organic-Inorganic Hybrid Material Synthesis through Reactive Processing without Solvent, Polymer, 45, pp.1485-1493 2004 Brinker, C J., K D Keefer, D W Schaefer and C S Ashley Sol-Gel Transition in Simple Silicates, J Non-Cryst Solids, 48, pp.47-64 1982 Brinker, C J and G W Scherer Sol → Gel → Glass Gelation and Gel Structure, J Non-Cryst Solids, 70, pp.301-322 1985 Brinker, C J., G W Scherer and E P Roth So l→ Gel → Glass Physical and Structural Evolution During Constant Heating Rate Experiments, J Non-Cryst Solids, 72, pp.345-368 1985 Brinker, C J Hydrolysis and Condensation of Silicates - Effects on Structure, J NonCryst Solids, 100, pp.31-50 1988 Brinker, C J and G W Scherer Sol-Gel Science : The Physics and Chemistry of Sol-Gel Processing pp 2-11; 97-112; 212-213; 235-239; 454-477; 493-513; 841-868; Boston: Academic Press 1990 81 Bruin, S and K C Luyben, A.M Drying of Food Materials: a Review of Recent Developments In Advances in Drying, 1, ed by Mujumdar, A S., pp 155-215 Washington, D.C.: Hemisphere Publishing Corporation 1980 Caddock, B D and D Hull Influence of humidity on the cracking patterns formed during the drying of sol gel drops, J Mater Sci., 37, pp.825-834 2002 Cao, G Z and H Tian Synthesis of Highly Porous Organic/Inorganic Hybrids by Ambient Pressure Sol-Gel Processing, J Sol-Gel Sci Technol., 13, pp.305-309 1998 Chaker, J A., K Dahmouche, C V Santilli, S H Pulcinelli and A F Craievich Drying Study of Siloxane-PPG Nanocomposites, J Sol-Gel Sci Technol., 19, pp.137144 2000 Chambers, R C., W E Jones, Y Haruvy, S E Webber and M A Fox Influence of Steric Effects on the Kinetics of Ethyltrimethoxysilane Hydrolysis in a Fast Sol-Gel System, Chem Mat., 5, pp.1481-1486 1993 Chan, C K., I M Chu, C F Ou and Y W Lin Interfacial Interactions and Their influence to Phase Behavior in Poly(vinyl pyrrolidone)/Silica Hybrid Materials Prepared by Sol-Gel Process, Mater Lett., 58, pp.2243-2247 2004 Chan, C M., G Z Cao, H Fong, M Sarikaya, T Robinson and L Nelson Nanoindentation and Adhesion of Sol-Gel-Derived Hard Coatings on Polyester, J Mater Res., 15, pp.148-154 2000a Chan, C M., G Z Cao and T G Stoebe Net Shape Ceramic Microcomponents by Modified Sol-Gel Casting, Microsystem Technologies, 6, pp.200-204 2000b Clark, D E and K W Wistrom Fabrication of Homogenous Sol-Gel Derived Multiphase Materials Using Gelling Control Agents, USA Patent, 5,160,455 1992 Connolly, R., H Vaillancourt and J Subirana Thermomechanical behavior of epoxyaluminum composites used for soft tooling, Sampe J., 35, pp.34-42 1999 Cornelius, C J and E Marand Hybrid Silica-Polyimide Composite Membranes: Gas Transport Properties, J Membr Sci., 202, pp.97-118 2002 Cornie, J A Casting Tooling, USA Patent, 5,937,932 1999 Duarte, T P., F J Lino, A B de Magalhaes, R Neto and J M F Ferreira Conversion of rapid prototyping models into metallic tools by ceramic moulding - an indirect rapid tooling process, Int J Mater Prod Technol., 21, pp.317-330 2004 Fortes, M and M R Okos Drying Theories: Their Bases and Limitations as Applied to Foods and Grains In Advances in Drying, 1, ed by Mujumdar, A S., pp 119-154 Washington, D.C.: Hemisphere Publishing Corporation 1980 Fricke, J and A Emmerling Aerogels - Recent Progress in Production Techniques and Novel Applications, J Sol-Gel Sci Technol., 13, pp.299-303 1998 82 Gonzalezoliver, C J R., M Schneider, K Nawata and H Kusano Porous Silicate Beads by Gelation, J Non-Cryst Solids, 100, pp.274-277 1988 Grader, G S., Y DeHazan, D BravoZhivotovskii and G E Shter Effect of Aging on Nonhydrolytic Alumina Xerogels, J Sol-Gel Sci Technol., 10, pp.127-137 1997 Haranath, D., A V Rao and P B Wagh Influence of DCCAs on optical transmittance and porosity properties of TMOS silica aerogels, J Porous Mat., 6, pp.55-62 1999 Harris, B., R G Cooke, F W Hammett and R S Russell-Floyd Sol-Gel Composites - A Low Cost Manufacturing Route, Ind Ceram., 18, pp.33-37 1998 Hdach, H., T Woignier, J Phalippou and G W Scherer Effect of Aging and pH on the Modulus of Aerogels, J Non-Cryst Solids, 121, pp.202-205 1990 Honma, I., S Hirakawa, K Yamada and J M Bae Synthesis of Organic/Inorganic Nanocomposites Protonic Conducting Membrane through Sol-Gel Processes, Solid State Ion., 118, pp.29-36 1999 Hrubesh, L W Aerogel Applications, J Non-Cryst Solids, 225, pp.335-342 1998 Hu, Y and J D Mackenzie Rubber-Like Elasticity of Organically Modified Silicates, J Mater Sci., 27, pp.4415-4420 1992 Hung, K M and W D Yang Preparation and Characterization of TiO2-SiO2 Glass Eramics via the Sol-Gel Process by Adding Organic Additives, Mater Manuf Process., 17, pp.323-338 2002 Jones, R W Fundamental Principles of Sol-Gel Technology pp 49-51 Brookfield, VT: Institute of Metals 1989 Kamiya, K., T Yoko, T Sano and K Tanaka Distribution of Carbon Particles in Carbon/SiO2 Glass Composites Made from CH3Si(OC2H5)3 by the Sol-Gel Method, J Non-Cryst Solids, 119, pp.14-20 1990a Kamiya, K., T Yoko, K Tanaka and M Takeuchi Thermal Evolution of Gels Derived from CH3Si(OC2H5)3 by the Sol-Gel Method, J Non-Cryst Solids, 121, pp.182-187 1990b Kawaguchi, T., J Iura, N Taneda, H Hishikura and Y Kokubu Structural-Changes of Monolithic Silica-Gel During the Gel-to-Glass Transition, J Non-Cryst Solids, 82, pp.50-56 1986 Kim, G D., D A Lee, J W Moon, J D Kim and J A Park Synthesis and Applications of TEOS PDMS Hybrid Material by the Sol-Gel Process, Appl Organomet Chem., 13, pp.361-372 1999 Kirkbir, F., H Murata, D Meyers and S R Chaudhuri Drying of Aerogels in Different Solvents between Atmospheric and Supercritical Pressures, J Non-Cryst Solids, 225, pp.14-18 1998 83 Kistler, S S Coherent Expanded Aerogels, J Phys Chem., 36, pp.52-64 1932 Klein, L C Filters and Membranes by the Sol-Gel Process In Sol-Gel Technology for Thin films, Fibers, Preforms, Electronics, and Specialty Shapes, ed by Klein, L C., pp 382-398 Park Ridge, N J U.S.A.: Noyes Publications 1988 Kocon, L., F Despetis and J Phalippou Ultralow Density Silica Aerogels by Alcohol Supercritical Drying, J Non-Cryst Solids, 225, pp.96-100 1998 Kotoky, T and S K Dolui Synthesis and Characterisation of Polyvinyl Alcohol (PVA)/Silica Hybrid Composites Derived through the Sol-Gel Method in Aqueous Medium: Effect of Acid Content, Silica Content and Viscosity of PVA on the Dispersion Characteristics of Silica and the Physical Properties of the Composites, J Sol-Gel Sci Technol., 29, pp.107-114 2004 Krihak, M and M R Shahriari The Effect of MTMS on the Optical Properties of TEOS Synthesized Gels Doped with Thionin, Opt Mater., 5, pp.301-310 1996 Kuramoto, K., H Izu, K Yamano and H Hirano Method of Producing OrganicInorganic Composite Material and Organic-Inorganic Composite Material, USA Patent, 6,723,770 2004 Landry, C J T., B K Coltrain and B K Brady Insitu Polymerization of Tetraethoxysilane in Poly(Methyl Methacrylate) - Morphology and Dynamic Mechanical-Properties, Polymer, 33, pp.1486-1495 1992 Launer, P J Infrared Analysis of Organosilicon Compounds: Spectra-Structure Correlations In Silicone Compounds Register and Review, ed by Arkles, B., pp 100105 Bristol, PA, USA: Petrarch Systems 1987 Lenza, R F S and W L Vasconcelos Synthesis and Properties of Microporous SolGel Silica Membranes, J Non-Cryst Solids, 273, pp.164-169 2000 Lenza, R F S and W L Vasconcelos Preparation of Silica by Sol-Gel Method Using Formamide, Mat Res, 4, pp.189-194 2001 Lewis, W and G Galic Low Cost, Blush-Resistant Silane/Silica Sol Copolymer Hardcoat for Optical Clear Plastics, USA Patent, 5,665,814 1997 Lu, L., J Y H Fuh and Y S Wong Laser-Induced Materoals and Processes for Rapid Prototyping pp xi-xiii Boston: Kluwer Academic Publishers 2001 Mackenzie, J D., Y J Chung and Y Hu Rubbery Ormosils and Their Applications, J Non-Cryst Solids, 147, pp.271-279 1992 Mackenzie, J D Present and Future Directions in Sol-Gel Science and Technology In Ceramic Transactions (Sol-Gel Science and Technology), 55, ed by Pope, E J A., pp 25-31 Westerville, Ohio: American Ceramic Society 1995 Malzbender, J and G de With Elastic Modulus, Hardness and Fracture Toughness of SiO2-Filled Methyltrimethoxysilane Coatings on Glass Substrates, J Non-Cryst Solids, 265, pp.51-60 2000 84 Matejka, L., J Plestil and K Dusek Structure Evolution in Epoxy-Silica Hybrids: Sol-Gel Process, J Non-Cryst Solids, 226, pp.114-121 1998 Mori, T., M T M Ikejiri, M Takei, M Aoki, S Uchiyama and S Kanbe Silica Glass Tubes by New Sol-Gel Method, J Non-Cryst Solids, 100, pp.523-525 1988 Nikolic, L and L Radonjic Effect of Drying Control Chemical Additives in Sol-GelGlass Monolith Processing, Ceram Int., 20, pp.309-313 1994 Niznansky, D and J L Rehspringer Infrared Study of Sio2 Sol to Gel Evolution and Gel Aging, J Non-Cryst Solids, 180, pp.191-196 1995 Orcel, G., L L Hench, I Artaki, J Jonas and T W Zerda Effect of Formamide Additive on the Chemistry of Silica Sol Gels Gel Structure, J Non-Cryst Solids, 105, pp.223-231 1988a Orcel, G., J Phalippou and L Hench Structural Evolution at Low-Temperature of Formamide Modified Silica Xerogels, J Non-Cryst Solids, 104, pp.170-180 1988b Parashar, V K., V Raman and O P Bahl The Role of N, N, Dimethylformamide and Glycol in the Preparation and Properties of Sol-Gel Derived Silica, J Mater Sci Lett., 15, pp.1403-1407 1996 Parmenter, K E and F Milstein Mechanical Properties of Silica Aerogels, J NonCryst Solids, 223, pp.179-189 1998 Phalippou, J Processing of Monolithic Ceramics via Sol-Gel In Chemical Processing of Ceramics, 8, ed by Lee, B I and E J A Pope, pp 265-285 New Yoke, Basel, Hong Kong: Marcel Dekker Inc 1994 Philipp, G and H Schmidt New Materials for Contact-Lenses Prepared from SiAlkoxides and Ti-Alkoxides by the Sol-Gel Process, J Non-Cryst Solids, 63, pp.283292 1984 Pope, E J A and J D Mackenzie Sol-Gel Processing of Silica the Role of the Catalyst, J Non-Cryst Solids, 87, pp.185-198 1986 Pouxviel, J C., J P Boilot, J C Beloeil and J Y Lallemand Nmr-Study of the SolGel Polymerization, J Non-Cryst Solids, 89, pp.345-360 1987 Que, W X., Y Zhou, Y L Lam, Y C Chan and C H Kam Preparation and characterizations of TiO2/organically modified silane composite materials produced by the sol gel method, J Sol-Gel Sci Technol., 20, pp.187-195 2001 Rabinovich, E M Particulate Silica Gels and Glasses from the Sol-Gel Process In Sol-Gel Technology for Thin Films, Fibers, Preforms, Electronics, and Specialty Shapes, ed by Klein, L C., pp 260-294 Park Ridge, New York: Noyes Publications 1988 Rangarajan, B and C T Lira The Effect of Aging on Acid-Catalyzed Aerogels, J Non-Cryst Solids, 136, pp.111-118 1991 85 Rao, A V and D Haranath Effect of Methyltrimethoxysilane as a Synthesis Component on the Hydrophobicity and Some Physical Properties of Silica Aerogels, Microporous Mesoporous Mat., 30, pp.267-273 1999 Rao, A V., H M Sakhare, A K Tamhankar, M L Shinde, D B Gadave and P B Wagh Influence of N,N-Dimethylformamide Additive on the Physical Properties of Citric Acid Catalyzed TEOS Silica Aerogels, Mater Chem Phys., 60, pp.268-273 1999 Rao, A V and G M Pajonk Effect of Methyltrimethoxysilane as a Co-Precursor on the Optical Properties of Silica Aerogels, J Non-Cryst Solids, 285, pp.202-209 2001 Russellfloyd, R S., B Harris, R W Jones, R G Cooke, T H Wang, J Laurie and F W Hammett Sol-Gel Processing of Fiber-Reinforced Ceramic Shapes, Br Ceram Trans., 92, pp.8-12 1993 Sanchez, C., B Lebeau, F Ribot and M In Molecular Design of Sol-Gel Derived Hybrid Organic-Inorganic Nanocomposites, J Sol-Gel Sci Technol., 19, pp.31-38 2000 Santos, A M M and W L Vasconcelos Obtention of Nanostructured Silica Glass by Sol-Gel Process with Incorporation of Lead Compounds, Mat Res., 2, pp.201-204 1999 Santos, E P., C V Santilli and S H Pulcinelli Effect of Aging on the Stability of Ceramic Foams Prepared by Thermostimulated Sol-Gel Process, J Sol-Gel Sci Technol., 26, pp.165-169 2003 Scherer, G W and J C Luong Glasses from Colloids, J Non-Cryst Solids, 63, pp.163-172 1984 Scherer, G W Drying Gels Warping Plate, J Non-Cryst Solids, 91, pp.83-100 1987 Scherer, G W Effect of Shrinkage on the Modulus of Silica-Gel, J Non-Cryst Solids, 109, pp.183-190 1989 Scherer, G W Drying of Gels In Ceramic Transactions (Sol-Gel Science and Technology), 55, ed by Pope, E J A., S Sakka and L C Klein, pp 181-220 Westerville Ohio: The American Ceramic Society 1995a Scherer, G W Aging of Gels In Ceramic Transactions (Sol-Gel Science and Technology), 55, ed by Pope, E J A., S Sakka and L C Klein, pp 153-180 Westerville Ohio: The American Ceramic Society 1995b Schmidt, H New Type of Non-Crystalline Solids between Inorganic and Organic Materials, J Non-Cryst Solids, 73, pp.681-691 1985 Schmidt, H Chemistry of Material Preparation by the Sol-Gel Process, J Non-Cryst Solids, 100, pp.51-64 1988 86 Schmidt, M and F Schwertfeger Applications for Silica Aerogel Products, J NonCryst Solids, 225, pp.364-368 1998 Schubert, U., N Husing and A Lorenz Hybrid Inorganic-Organic Materials by SolGel Processing of Organofunctional Metal Alkoxides, Chem Mat., 7, pp.2010-2027 1995 Smith, D M., D Stein, J M Anderson and W Ackerman Preparation of LowDensity Xerogels at Ambient-Pressure, J Non-Cryst Solids, 186, pp.104-112 1995 Sowman, H G Internally Modified Ceramic Fiber, Eur Pat App Patent, 87,301,350 1987 Statham, M J., E Hammett, B Harris, R G Cooke, R M Jordan and A Roche Netshape manufacture of low-cost ceramic shapes by freeze-gelation, J Sol-Gel Sci Technol., 13, pp.171-175 1998 Stober, W., A Fink and E Bohn Controlled Growth of Monodisperse Silica Spheres in Micron Size Range, J Colloid Interface Sci., 26, pp.62-69 1968 Stober, W., C Boose and H Flachsba Distribution Analyses of Aerodynamic Size and Mass of Aerosol Particles by Means of Spiral Centrifuge in Comparison to Other Aerosol Precipitators, J Colloid Interface Sci., 39, pp.109-120 1972 Stocker, C and A Baiker Zirconia Aerogels: Effect of the Use of Mono-and Dicarboxylic Acids in the Sol-Gel Process on Structural Properties, J Sol-Gel Sci Technol., 10, pp.269-282 1997 Tay, F E H., E A Haider, M Rahman, J Y Lee and T E H Ong Manufacture of RP Tools with High Quality Surface Finish Using High Temperature Epoxy Resin and Electroless Nickel Plating, Surface Engineering, 16, pp.250-252 2000 Thomas, I M Method for Manufacturing Silicate Glasses from Alkoxides, USA Patent, 4,028,085 1977 Uchida, N., N Ishiyama, Z Kato and K Uematsu Chemical Effects of Dcca to the Sol-Gel Reaction Process, J Mater Sci., 29, pp.5188-5192 1994 Uhlmann, D R., J M Boulton and G Teowee New Optical Materials by Wet Chemical Processing, J Non-Cryst Solids, 196, pp.26-36 1996 Uhlmann, D R., T Suratwala, K Davidson, J M Boulton and G Teowee Sol-Gel Derived Coatings on Glass, J Non-Cryst Solids, 218, pp.113-122 1997 Vanbommel, M J., T N M Bernards and A H Boonstra The Influence of the Addition of Alkyl-Substituted Ethoxysilane on the Hydrolysis Condensation Process of TEOS, J Non-Cryst Solids, 128, pp.231-242 1991 Wang, S., F Kirkbir, S Raychaudhuri and A Sarkar Process for Rapidly Drying a Wet, Porous Gel Monolith, USA Patent, 5,243,769 1993 87 Wang, S., F Kirkbir, S Raychaudhuri and A Sarkar Apparatus for Rapidly Drying a Wet, Porous Gel Monolith, USA Patent, 5,343,633 1994 Wang, S Y and N L Wu Tin Oxide Gel Shrinkage during CO2 Supercritical Drying, J Non-Cryst Solids, 224, pp.259-266 1998 Wei, Y., D L Jin, C C Yang and G Wei A fast convenient method to prepare hybrid sol gel materials with low volume-shrinkages, J Sol-Gel Sci Technol., 7, pp.191-201 1996 Wicks, G G Ceramic composite coating, USA Patent, 5,595,945 1997 Wood, T E and H Dislich An Abbreviated History of Sol-Gel Technology In Ceramic Transactions (Sol-Gel Science and Technology), 55, ed by Pope, E J A., S Sakka and L C Klein, pp 3-23 Westerville, Ohio: The American Ceramic Society 1995 Wright, J D and N A J M Sommerdijk Sol-Gel Materials : Chemistry and Applications pp 1-13; 24-28; 36-37; 41-44; Amsterdam: Gordon & Breach Science 2000 Yano, S., M Kodomari and T Furukawa Preparation and Properties of Poly(vinyl acetate)silica-Gel Hybrids Obtained by Sol-Gel Process: Effect of Methyl Groups in Silicon Alkoxide, Key Eng Mat., 150, pp.219-226 1998 Zarzycki, J., M Prassas and J Phalippou Synthesis of Glasses from Gels: the Problem of Monolithic Gels, J Mat Sci., 17, pp.3371-3379 1982 88 ... reinforcement phase, or both in the composites Sol gel composites comprise inorganic- inorganic composites and organic- inorganic composites By doping ceramic reinforcement phase in inorganic sol gel. . .DEVELOPMENT OF ORGANIC/ INORGANIC COMPOSITES BY SOL GEL METHOD FOR TOOLING MATERIALS LIU FENGMIN (B Eng., Beijing University of Aeronautics & Astronautics) A THESIS SUBMITTED FOR THE DEGREE OF. .. volume of SiC-filled 61 organic/ inorganic composites Figure 4-14 Thermal conductivity of different volume of SiO2-filled 62 organic/ inorganic composites Figure 4-15 Organic/ inorganic composites