Дисертації з теми "Thermoplastic polyurethane nanocomposites"

This thesis is concerned with fused filament fabrication (FFF) of cellulose nanocrystal (CNC) and thermoplastic polyurethane (TPU) nanocomposites, focusing on preliminary optimization of a processing window for 3D printing of mechanically responsive composites and the influence of temperature on mechanical adaptivity, thermal stability, and rheology. CNC thermoplastic nanocomposites are a water responsive, mechanically adaptive material that has been gaining interest in additive manufacturing for 4D-printing applications. Using a desktop FlashForge Pro 3D printer, we first established a viable processing window for a nanocomposite comprising 10 wt% CNCs in a thermoplastic urethane (TPU) matrix, formed into a filament through the combination of masterbatch solvent casting and single screw extrusion. Printing temperatures of 240, 250, and 260°C and printing speeds of 600, 1100, and 1600 mm/min instituted a consistent 3D-printing process that produced characterizable CNC/TPU nanocomposite samples. To distinguish the effects of these parameters on the mechanical properties of the printed CNC/TPU samples, a design of experiments (DOE) with two factors and three levels was implemented for each combination of printing temperature and speed. Dynamic mechanical analysis (DMA) highlighted 43 and 66% increases in dry-state storage moduli values as printing speed increases for 250 and 260°C, respectively. 64 and 23% increases in dry-state storage moduli were also observed for 600 and 1100 mm/min, respectively, as temperature decreased from 260 to 250°C. For samples printed at 240°C and 1600 mm/min, it was determined that that parameter set may have fallen out of the processing window due to inconsistent deposition and lower dry-state storage moduli than what the slower speeds exhibited. As a result, the samples printed at 240°C did not follow the same trends as 250 and 260°C. Further analysis helped determine that the thermal energy experienced at the higher end printing temperatures coupled with the slower speeds decreased the dry-state storage moduli by nearly 50% and lead to darker colored samples, suggesting CNC degradation. Isothermal thermogravimetric analyses (TGA) demonstrated that the CNC/TPU filament would degrade at relative residence times in the nozzle for all the chosen printing temperatures. However, degradation did not eliminate the samples' ability to mechanically adapt to a moisture-rich environment. DMA results verified that mechanical adaptivity was persistent for all temperature and speed combinations as samples were immersed in water. However, for the higher temperatures and slower speeds, there was about a 15% decrease in adaptability. Optimal parameters of 250°C and 1600 mm/min provided the highest dry-state storage modulus of 49.7 +/- 0.5 MPa and the highest degree of mechanical adaptivity of 51.9%. To establish the CNC/TPU nanocomposite's use in 4D printing applications, shape memory analysis was conducted on a sample printed at the optimal parameters. Multiple wetting, straining, and drying steps were conducted to highlight 76% and 42% values for shape fixity and shape recovery, respectively. Furthermore, a foldable box was printed to serve as an example of a self-deployable structure application. The box displayed shape fixity and recovery values of 67% and 26%, respectively, further illustrating significant promise and progress for CNC/TPU nanocomposites in 4D-printed, shape adaptable structures. Further analysis of the effect of degradation during FFF of the CNC/TPU nanocomposite was conducted using rotational rheometry, Fourier-Transform Infrared Spectroscopy (FTIR), and polymer swelling experiments. A temperature ramp from 180 to 270°C showed a significant increase in complex viscosity (h*) at the chosen printing temperatures (240, 250, and 260°C). Moreover, h* of neat TPU suddenly increases at 230°C, indicating a potential chemical crosslinking reaction taking place. 20-minute time sweeps further verified that h* increases along with steady increases in storage (G') and loss (G'') moduli. From these results, it was hypothesized that crosslinking is occurring between CNCs and TPU. Preliminary characterization with FTIR was used to probe the molecular structure of thermally crosslinked samples. At 1060 and 1703 cm-1, there are significant differences in intensities (molecular vibrations) as the temperature increases from 180 to 260°C related to primary alcohol formation and hydrogen bonded carbonyl groups, respectively. The hypothesis is the disassociation of TPU carbamate bonds into soft segments with primary alcohols and hard segments with isocyanate groups. The subsequent increasing peaks at 1060 and 1703 cm-1 may indicate crosslinking of CNCs with these disassociated TPU segments. To quantify potential crosslinking, polymer swelling experiments were implemented. After being submerged in dimethylformamide (DMF) for 24 hours, CNC/TPU samples thermally aged for 15 minutes at 240, 250, and 260°C retained their filament shape and did not dissolve. The 240 and 250°C aged samples had relatively similar crosslink densities close to 900 mole/cm3. However, from 250 to 260°C, there was about a 36% increase in crosslink density. These results suggest that crosslinking is occurring at these printing temperatures because both CNCs and TPU are thermally degrading into reactive components that will lead to covalent crosslinks degradation. Additional characterization is needed to further verify the chemical structure of these CNC/TPU nanocomposites which would provide significant insight for CNC/TPU processing and 3D printing into tunable printed parts with varying degrees of crosslinking.
Master of Science
This thesis is concerned with the development of a processing window for mechanically adaptive cellulose nanocrystal (CNC) and thermoplastic polyurethane (TPU) nanocomposites with fused filament fabrication (FFF) and, evaluating the influence of elevated temperatures on the mechanical, thermal, and rheological properties of said nanocomposite. CNC thermoplastic nanocomposites are a water responsive, mechanically adaptive material that has been gaining interest in additive manufacturing for 4D-printing. Using a desktop 3D-printer, an initial processing window for a 10 wt% CNC in TPU was established with printing temperatures of 240, 250, and 260°C and printing speeds of 600, 1100, and 1600 mm/min. A design of experiments (DOE) was implemented to determine the effects of these parameters on the mechanical properties and mechanical adaptability of printed CNC/TPU parts. Dynamic mechanical analysis (DMA) suggests that combinations of higher temperatures and lower speeds result in reduced storage moduli values for printed CNC/TPU parts. However, mechanical adaptation, or the ability to soften upon water exposure, persists for all the printed samples. Additionally, there was significant discolorations of the printed samples at the higher temperature and slower speed combinations, suggesting thermal degradation is occurring during the printing process. The decrease in storage moduli and discoloration is attributed to thermal energy input, as thermogravimetric analysis indicated thermal degradation was indeed occurring during the printing process regardless of printing temperature. Using the parameters (250°C and 1600 mm/min) that displayed the superior mechanical properties, as well as mechanical adaptivity, shape memory analysis was conducted. The optimal printed part was able to hold 76% of the shape it was strained to, while recovering 42% of the original unstrained shape once immersed in water, indicating potential for shape memory and 4D-printing applications. Furthermore, a foldable box was printed with the optimal parameters and it displayed similar shape memory behavior, illustrating promise for CNC/TPU self-deployable shape adaptable structures. To further study the effect of degradation on the CNC/TPU system, melt flow properties, molecular structure, and polymer swelling were investigated. At the printing temperatures (240, 250, and 260°C), the complex viscosity of the CNC/TPU filament experienced an exponential increase, indicating potential network formation between the CNCs and TPU. Fourier-Transform Infrared Spectroscopy (FTIR) highlighted changes in the molecular structure for the CNC/TPU filament as temperature increased from 240 to 260°C, which suggests that chemical structure changes are occurring because of degradation. The hypothesis is TPU is disassociated into free soft and hard segments that the CNCs can covalently crosslink with, which can potentially be explained by the increases in the FTIR intensities relating to TPU and CNC's chemical structure. To further quantify potential crosslinking between CNCs and TPU, polymer swelling experiments were implemented. The results from these experiments suggest that increasing printing temperatures from 240 to 260°C will lead to higher degrees of crosslinking. Further investigation could yield the validity of this crosslinking and additional optimization of FFF printing with CNC/TPU nanocomposites.

This dissertation focuses on the versatility and integrity of a novel, ultrasoft polycarbonate polyurethane (PCPU) by the introduction of nanoparticles and lithium salts. Additionally, the research takes into account the use of electrospinning as a technique to create PCPU and polyimide (PI) fibers. These polymers are of interest as they offer a wide range of properties and uses within the medical and industrial fields. An industrial batch of an ultrasoft thermoplastic polyurethane (TPU) was synthesized using a two-step process. The first was to create an end capped pre-polymer from methylene bis (4-cyclohexylisocyanate), and a polycarbonate polyol made up of 1,6- hexanediol and 3-methyl-1,5-pentanediol. The second step was done by reacting the pre-polymer with an excess of the polycarbonate polyol with a chain extender, 1,4-butanediol. Biocompatibility testing such as USP Class VI, MEM Elution Cytotoxicity and Hemolysis toxicology reported that PCPU showed no toxicity. This novel type of polyurethane material targets growing markets of biocompatible polymers and has been used for peristaltic pump tubing, but also can be utilized as balloon catheters, enteral feeding tubes and medical equipment gaskets and seals. This material is ideal for replacing materials such as soft plastisols containing diethylhexyl phthalate for use in biomedical and industrial applications. After extensive characterization of this polymer system another dimension was added to this research. The addition of nanoparticles and nanofillers to polyurethane can express enhanced mechanical, thermal and adhesion properties. The incorporation of nanoparticles such as nanosilica, nanosilver and carbon black into polyurethane materials showed improved tensile strength, thermal performance and adhesion properties of the PCPU. Samples were characterized using contact angle measurements, Fourier transform spectroscopy (FTIR), differential scanning calorimetry (DSC), parallel plate rheology and tensile testing. The second chapter entails the fabrication and characterization of PCPU nanofibers and nanomembranes through a process known as electrospinning. The resulting PCPU nanomembranes showed a crystalline peak from the WAXS profile which is due to electrospun and solution strain induced crystallinity. The PCPU nanocomposite nanomembranes displayed increased thermal stability and an increase in tensile performance at higher weight percent. The nanomembranes were investigated using contact angle measurements, thermogravimetric analysis (TGA), DSC, WAXS, SAXS and tensile testing. The final chapter focuses on investigating the rheological properties of PCPU/lithium electrolytes as well as transforming an unprocessable polyimide powder into a nanomembrane. The PCPU/ lithium composite electrolyte showed an increase in the activation energy and conductivity, while the PI/lithium showed increased conductivity over time. Dynamic mechanical analysis and four-point probe was used to investigate the samples.

Neste trabalho foram obtidos nanocompósitos contendo 0, 1, 2, 5 e 10% (m/m) de argila organofílica montmorilonita cloisite 30B, contendo terminações hidroxila, por processamento reativo entre um pré-polímero com terminações isocianato e o 1,4-butanodiol, utilizando-se um misturador fechado. Os resultados mostraram que os poliuretanos termoplásticos sintetizados foram obtidos com sucesso. A adição de montmorilonita nos TPUs ocasionou a formação de folhas de argila dispersas de maneira intercalada, parcialmente esfoliada, esfoliada e aglomerados na matriz do TPU. Com a adição da argila houve modificações nos comportamentos de cristalização, estabilidade térmcica e mecanismo de degradação, assim como um aumento nos valores de energia aparente de ativação deste processo. A mobilidade de alguns segmentos poliméricos também foi alterada com a adição da argila. Portanto modificações morfológicas e viscoelásticas foram observadas para os nanocompósitos em dependência da quantidade de argila organofílica empregada, assim como a adição da organoargila alterou o comportamento térmico do poliuretano termoplástico, tornando os nanocompósitos mais suscetíveis a mudanças nos processos de fusão e cristalização em função da exposição a temperaturas elevadas.
In this study, were obtained nanocomposites containing 0, 1, 2, 5 and 10% (w/w) of organophilic clay montmorillonite Cloisite 30B, containing hydroxyl terminations, by reactive processing between a prepolymer with isocyanate terminations and 1,4-butanediol, using a closed mixer. The analysis showed that the obtained thermoplastic polyurethanes were synthesized successfully. The addition of the montmorillonite in the TPUs resulted in the formation of sheets of clay dispersed in order intercalated, partially exfoliated, exfoliated and agglomerate in the TPU matrix. With the addition of clay there were changes in the behavior of crystallization, thermal stability and degradation mechanism, as well as an increase in the values of the apparent activation energy of this process. The mobility of certain polymer segments was also changed with the addition of the clay. Therefore viscoelastic and morphological changes were observed in the nanocomposites in dependence on the amount of organophilic clay used, as well as the addition of the organophilic decreased the thermal stability of the thermoplastic polyurethane, making nanocomposites more susceptible to changes in the melting and crystallization processes due to exposure to elevated temperatures.

The advancement of each component of aerospace vehicles is necessary as the continual demand for more aggressive missions are created. Improvements in propulsion and guidance system electronics are invaluable; however without material development to protect the vehicle from its environment those advances will not have a practical application. Thermal protection systems (TPS) are required in both external applications; for example on reentry vehicles, as well as in internal applications; to protect the casing of rockets and missiles. This dissertation focuses on a specific type of internal solid rocket motor TPS, ablatives. Ablatives have been used for decades on aerospace vehicles. To protect the motor from the hostile environment, these materials pyrolyze and char. Both of these mechanisms produce a boundary between the combustion gases and the motor as well as release the heat that the decomposed material has absorbed. These sacrificial materials are intended to protect the casing that it is attached to. With the development of polymer nanocomposites (PNCs) in the last couple of decades, it is of interest to see how these two fields can merge. Three different nanomaterials (carbon nanofibers, multiwall carbon nanotubes, and nanoclays) are examined to observe how each behaves in environments that simulate the motor firing conditions. These nanomaterials are individually added to a thermoplastic polyurethane elastomer (TPU) at different loadings, creating three distinct families of polymer nanocomposites. To describe a materials ablative performance, a number of material properties must be individually studied; such as thermal, density, porosity, char strength, and rheology. Different experiments are conducted to isolate specific ablative processes in order to identify how each nanomaterial affects the ablative performance. This dissertation first describes each material and the ablative processes which are characterized by each experiment. Then basic material properties of each family of materials are described. Degradation and flammability experiments then describe the degassing processes. Studies of the material char are then performed after full blown rocket experiments are done. These tests have shown that of the three nanomaterials, nanoclay enhances the TPU ablative performance the most while the CNF provides the least enhancement.
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碩士
國立中興大學
化學工程學系
90
Abstract The MMT-master batch is introduced in proportion to the matrix of Thermolplastic Polyurethane (TPU) by kneading process to prepare nanocomposites in this study. This master batch is prepared by the negatively charged MMT adsorbed with cationic polyelectrolytes in the water phase and then “coagulated” with negatively charged Polyurethane Dispersion (PUD). Characterized by FTIR and DSC, the compatibility of PUD with TPU matrix of the master batch is confirmed. The result of XRD demonstrated that the d-spacing of MMT is greater than 4.4 nm. The storage modulus, as compared with TPU, increased 59% at -100℃ and 43% at 25℃, respectively at 5 wt% MMT loading. The tensile strength and elongation at break of TPU nanocomposite at 3 wt % MMT also increases 38% and 23%, respectively. In this research, we demonstrated the preparation of TPU/MMT nanocomposite by kneading process with improved mechanical and thermal properties as compared with those of TPU.

碩士
國立臺北科技大學
化學工程研究所
100
In this study, thermoplastic polyurethane (TPU) was foamed by batch foaming using CO2 as the blowing agent, and the effect of saturation temperature on cell morphology TPU foam was examined. Five different nanoparticles were compounded with TPU as the nucleation agent. Among the five different nanoparticles(Clay30B、Clay20A、CNT、CNF、H05), Clay30B seems to be the best nucleation agent, because it had the smallest cell size and the highest cell density in the result of batch foaming. Adding 1wt% 30B nanoclay resulted in submicron sized foam. With the increasing content of Clay30B led to increase in the cell density, while the foam density decreases. The cell size could be as low as 450 nm while the cell density could be as high as 1011 cells/cm3. Finally, the effect of cell morphology to the mechanical properties of foamed samples was also investigated. It was found that adding 1wt% nanoclay not only could improve the mechanical properties of the solid, it can also increase the modulus of the foamed nanocomposite significantly.

碩士
中國文化大學
化學工程與材料工程學系奈米材料碩士班
106
This project object is to manufacture thermoplastic polyurethane (TPU)/nano-SiO2 organic/inorganic nanocomposites by melt intercalation process, and study the processing method, morphology and properties of nanocomposites. In this study, using 3- (Trimethoxysilyl) propyl methacrylate (MPS) grafted nano silicon surface modification. For thermoplastic polyurethane (TPU) Add prepared SiO2 and MPS-m- SiO2 nanocomposites with a different number of grams of composition (per 100 grams of resin contained in the composition of the number of grams). To use the relationship properties of nano-SiO2 included high strength, high modulus, thermal resistance, flame resistance, abrasion resistance, excellent hardness and high chemical stability to increase the static mechanical properties (tensile, hardness, abrasion), dynamic mechanical properties (storage modulus, loss modulus, tan ) and thermal properties (Vicat softening temperature, TGA, DSC) of TPU resin. The experimental results that, by TGA, FT-IR, XRD and XPS testing can prove the success of silane coupling agent grafted via at particle size analysis, to retain the size of the reinforcing material in nano levels. thermoplastic polyurethane resin / silicon adding SiO2 and MPS-m- SiO2 part of the composite material, structure and morphology in SEM image that the addition of SiO2 and MPS-m- SiO2 allows more surface structures from the original hole into a smoother surface; a test of physical properties, effectively increasing; in mechanical properties test results, hardness and abrasion index, are all rising. The bending and tensile test, adding SiO2 or MPS-m- SiO2, its strength is rised; thermal properties, heat resistance improving effect is more significant; in terms of electrical properties, with SiO2 and MPS-m- SiO2 Add permittivity have to enhance the effect; transmittance affect optical properties, add more content SiO2 and MPS-m- SiO2, and will make it light transmission decreased, whereas the absorbance of a good promotion effect.

碩士
中國文化大學
化學工程與材料工程學系奈米材料碩士班
107
This project object is use the thermoplastic polyurethane (TPU) and nano titanium dioxide (TiO2) to uniformly mix the nanocomposites were uniformly mixed by a melt kneading machine, and the processing, optical properties, physical properties, mechanical properties, thermal properties and dynamic mechanical properties of the nanocomposites were investigated. Surface modified modifier is used 3-(Trimethoxysilyl) propyl methacrylate (MPS). It was grafted onto the surface of nano titanium dioxide, and it was verified by FT-IR, TGA, XRD whether the modification was successful. The polymer composite used in the experiment was prepared by adding unmodified nano titanium dioxide and modified nano titanium dioxide in proportion to thermoplastic polyurethane resin. 1, 3, 5 phr of a nanocom-posite compounded in a melt kneader (TPU per 100 g: 1 g, 3 g, 5 g of TiO2, m-TiO2). Study on the spectral analysis (Raman, FT-IR, XRD),optical properties (transparency),mechanical properties (tensile, impact, wear resistance, hardness) thermal properties (TGA, VST, MI) and thermal dynamic proper-ties (DMA).of TiO2 and MPS-m-TiO2 on different thermoplastic composites with different grams. Particle size analysis confirmed that the nano TiO2 be-fore and after the modification was in the nanometer grade. SEM showed good dispersion properties. The addition of nano TiO2 will enhance the thermal properties of this nanocomposite, and the heat resistance is also improved. In terms of mechanical properties, tensile strength, impact strength and hardness are also enhanced by the addition of nano TiO2. Therefore, this study shows that the addition of nano TiO2 can achieve the effect of strengthening thermoplastic polyurethane/nano titanium dioxide composite.

碩士
中原大學
化學研究所
102
This work focused on the pristine sodium montmorillonite clay (CL120) using the sol-gel method for surface modification, without the addition of the polymer to the substrate before pristine sodium montmorillonite clay can reach a certain degree of delamination of the structure. Surface modification of layered materials applied to thermoplastic polymer nanocomposites using by twin screw micro-compounder with thermoplastic polyurethane (TPU), and then made thin film of polymer nanocomposites by hot pressure method. Fourier transform infrared spectroscopy (FT-IR) is to identify the functional groups of modified montmorillonite, which would be bonded to the thermoplastic polyurethane and the results show TPU/CL120-SiO2 nanocomposites is compatible system for the blending process. X-ray diffraction pattern (XRD) and transmission electron microscopy (TEM) are applied to observe the dispersion of composites; TPU/CL120-SiO2 performed a small part of intercalation and majority of delamination patterns of inorganic layered materials. The decomposition temperature (Td) of TPU/CL120-SiO2- 5phr was maximum increased 8.3 ℃ from 305.8 ℃ to 314.1 ℃. The glass transition temperature (Tg) of TPU/CL120-SiO2-5phr in differential scanning calorimetry (DSC) was increased 5.18 ℃from -39.30 ℃to -34.12 ℃, and in the dynamic mechanical analyzer (DMA) was increased 8.88 ℃ from -42.55 ℃ to -33.67 ℃. The storage modulus of TPU/CL120-SiO2-5phr was increased 83 % due to the exfoliate nanostructure. Tensile strength, Modulus and Abrasion resistance of TPU/CL120-SiO2-9phr was the best, the tensile strength increased 68.13 % , 100% modulus increased 53.09 % and 300% modulus increased 42.75 %, the abrasion resistance increased 73.08%, and the elongation of TPU/CL120-SiO2-5phr enhance the better effect of 17.9%. In the optical properties, the UV resistance of TPU/CL120-SiO2-5phr was separately 4.9 % (375nm) and 10.6 % (320nm), and maintains a high visible light transmittance than the idealized. In the ultraviolet aging properties, TPU/CL120-SiO2-5phr of the resistance yellowing coefficient (△ YI) decreased from 16.68 to 13.20, yellowing resistance effect was increased to 20.86 %, TPU/CL120-SiO2-5phr of the color difference (△ E) decreased from 11.26 to 8.72, color effects to enhance 22.56 %, the degree of aging decreased from 25% to 19%,anti-aging effects to enhance 8%. Therefore, the performance of TPU/clay nanocomposites has shown the great improvement in various properties.

碩士
中原大學
化學研究所
93
This study reports on the electrical properties of the thermoplastic polyurethane (TPU) filled with two kinds of nickel-based metal particles. The fillers were different particle shells and sizes were nickel core nickel oxide shell (Ni/NiO 20~80 nm) powders and nickel core graphite shell (Ni/C 5~60 nm) powers. The results gave evidence of the non-conducting to conducting transition as the filler volume was increased over percolation threshold. TPU-Ni/NiO nanocomposite appeared at 35 vol. % and TPT-Ni/C nanocomposite appeared at 5 vol. %. The conductivity of fillers played an important role on dielectric properties. Composites of equivalent circuit models were builded by using impedance analyzer. The morphology of filler particles had been investigated by transmission electron microscopy (TEM) and scanning electron microscope (SEM).The electrical behavior of nanocomposites was discussed in point of view of particle shell and particle size.

Innovations in electronics and the rapid developments in communication systems have been unprecedented and made life easier. One such advancement is wireless electronics, where gadgets operate in gigahertz frequencies – transmitting and receiving signals in the form of EM waves during their operation. The increased presence of EM waves in the atmosphere has led to electromagnetic (EM) pollution. With the miniaturization of devices, there is an increased volume of complex circuitry in a limited space – causing interference between them during operation, termed “electromagnetic interference” (EMI). EMI concerns are rising as they are considered severe threats to devices and their functioning. Different shielding materials were developed to combat this issue, from metals and ferrites to polymer-based nanocomposites. As the filler loading in a polymer-based nanocomposite is limited by processing and the accompanying stiffness, textiles have emerged as alternative materials with a broad design scope. This thesis entitled, “Smart textiles with tuneable architectures for multifunctional applications,” attempts to develop novel multilayer-like architectures based on coatings to target EMI shielding primarily. Different materials and processes were adopted to maximize EMI shielding effectiveness, UV blocking, and fire protection. The thesis consists of 7 chapters. Chapter 1 is an introductory note on EMI shielding and textile-based EMI shielding materials. It discusses the terminologies used in EMI shielding, the fundamental shielding mechanisms, and the different phenomena causing attenuation. It presents a comprehensive overview of the evolution of textile-based EMI shields with time and explains the inherent advantages of using textiles as EMI shields over other materials. Chapter 2 is the roadmap of the thesis. It delves into the rationale behind selecting the materials and processes adopted. It explains the advancements in the different chapters, highlighting the critical aspects of each. In Chapter 3, thermoplastic polyurethane (TPU)-based coatings containing iron titanate (FT) and multiwalled carbon nanotubes (CNT) were coated onto cotton fabrics by a dip coating process. The coated fabrics showed an EMI SE of -12 dB at a thickness of 1.1 mm, working on an absorption-driven mechanism amounting to around ca. 92% of the total attenuation. They also demonstrated a 99.9% UV blocking and a limiting oxygen index (LOI) of 20%. In Chapter 4, water-borne coatings were used on pretreated cotton fabrics. Here, water-borne polyurethane (WPU) was used as the matrix for dispersing chemically coupled CNT and FT. The coating was subsequently coated onto polyaniline-coated cotton fabric (PANi-CF) prepared by an in-situ polymerization route. The coated fabrics exhibited an EMI SE of -40 dB at a thickness of 2.4 mm, with the absorption contribution being 83%. They also demonstrated a 99.99% UV blocking and an LOI of 23%. Further, in Chapter 5, an attempt was made to study the effect of different conducting polymer pretreatments on cotton fabric on EMI shielding. Using a facile in-situ polymerization technique, two different conducting polymers, polyaniline and polypyrrole, were coated onto cotton fabrics to give PANi-CF and PPy-CF, respectively. A carbonaceous layer containing graphene nanoplatelets (GNP) and carbon nanofibers (CNF) dispersed in WPU was coated on both the pretreated cotton fabrics. PPy-CF showed better EMI SE (-22 dB), UV blocking (99.99%), and LOI (25%) than PANi-CF. The plausible reasons for the enhancement in properties are explained in this chapter. Chapter 6 adopted a facile mussel-inspired electroless deposition to deposit metallic silver on cotton fabric (giving Ag-CF). The deposition process was optimized by varying the seeding time to enhance the silver loading on the fabric surface. The Ag-CF was coated with the same carbonaceous layer mentioned above (GNP and CNF dispersed in WPU) to give a ‘hybrid textile.’ The hybrid textile showed an EMI SE of -50 dB, the maximum obtained in this thesis, due to ‘absorption-reflection-absorption’ with absorption percentages going as high as 94%. The UV blocking and LOI values also reached 99.999% and 27%, respectively. Chapter 7 presents a consolidated summary of the results obtained from the different chapters. It also suggests a possible extension of the work that could be done to enhance the multifunctional aspects of the coated fabric.