Skip to main content

Dr. Bapan Adak

Nanyang Technological University, Materials Science and Engineering, Post-Doc

IIT Delhi, Textile & Fibre Engineering, Post-Doc

Followers

178

Following

55

Co-authors

3

Mentions

1

Public Views

Current profile: Research Scientist at NTU Singapore
Previous affiliations:
#PhD and MTech: IIT Delhi
#Principal Project Scientist: IIT Delhi
#Senior Manager: Kusumgar Corporates Pvt Ltd
#Manufacturing Manager: Arvind Ltd
Phone: +91-9716634787
Address: IITD, Hauz Khas, New Delhi, India

less

Eija-Katriina Uusi-Tarkka

University of Eastern Finland

Aalto University

University of Coimbra

University of Canterbury/Te Whare Wānanga o Waitaha

mohd zaim jaafar

University Sains MalaysiaN

Interests

Uploads

Papers by Dr. Bapan Adak

Effect of pressure on structure and properties of lyocell fabric-based all-cellulose composite laminates

Journal of The Textile Institute, Jul 20, 2016

In this work, all-cellulose composite (ACC) laminates were manufactured from lyocell fabric using... more In this work, all-cellulose composite (ACC) laminates were manufactured from lyocell fabric using a simple hand lay-up and compression molding-based surface-selective dissolution technique. In dissolution step, temperature and dissolution time were fixed and pressure varied. Subsequently, the dissolved cellulose was regenerated via solvent exchange and then dried by hot-pressing. The microstructures of ACC laminates were analyzed by scanning electron microscope micrographs and measuring void content. Optimum microstructure and mechanical properties were obtained with a pressure of 1 MPa, but slightly deteriorated with further increase in pressure. The highest tensile strength and modulus achieved were 44.24 ± 2.2 MPa and 1.78 ± 0.14 GPa, respectively, for ACC-3. Best flexural strength and modulus obtained were 48.95 ± 2.87 MPa and 0.96 ± 0.21 GPa, respectively, for the same sample. The T-peel strength of ACC-3 also was very high, 2.78 ± 0.34 MPa. Application of pressure during drying had a great role on controlling shrinkage and internal voids in ACC laminates.

Cellulose based flexible and wearable sensors for health monitoring

Materials Advances

Cellulose is one of the greatest bio-resourced materials. In this review, the excellent advanceme... more Cellulose is one of the greatest bio-resourced materials. In this review, the excellent advancement of cellulose-based sensors for wearable real-time health monitoring are described. In addition, the emerging prospects and challenges of cellulose based flexible devices within this fields are also presented.

Cellulose based flexible and wearable sensors for health monitoring

Materials advances, 2022

Recently, with the advancement of materials science and manufacturing methods, researchers have i... more Recently, with the advancement of materials science and manufacturing methods, researchers have introduced many new and advanced materials for wearable sensors. In particular, incredible advancement has been made in flexible strain sensors for their application in wearable health monitoring, soft-robotics, human-machine interactions (HMI), and so forth. Cellulose, the most abundant natural biopolymer, is one of the most viable substrates for strain and pressure sensors, mainly due to its biocompatibility and biodegradability along with many other useful features. Cellulose is available in various forms including fibers, nanocrystals, and nanofibers, and different techniques are used to fabricate these into hydrogels, aerogels, films, paper, fabrics, and eventually into sensors. An overview of the fabrication, sensing performance, and applications of cellulose-based flexible physiological sensors has been presented in this review, along with their use in monitoring healthcare activities through different types of strain sensors, pressure sensors and HMIs. It is observed that an appropriate selection of the substrate and functional materials greatly influence the sensing characteristics of these sensors, such as sensitivity, response time, effective strain range, stability under strain/pressure, and hysteresis. The potential for further research on this subject has also been highlighted, along with the recent trends in using flexible sensors for health-monitoring.

A synergy of atmospheric plasma and UV-additive incorporated PU and styrene-isoprene-styrene adhesive for improving inter-layer adhesion in PVF/Fabric/BOPET laminate for aerostat envelope

Composites Part A-applied Science and Manufacturing, Oct 1, 2023

1 Introduction to functional, smart, and intelligent textiles: perspectives and potential applications

De Gruyter eBooks, Mar 20, 2023

Introduction to LTA Systems

CRC Press eBooks, Feb 3, 2022

Modelling for Performance Analysis of Aerostats/Airships

CRC Press eBooks, Feb 3, 2022

Applications, Current Difficulties, and Future Scope of Single-Polymer Composites

All-cellulose composite laminates with low moisture and water sensitivity

Polymer, Apr 1, 2018

A conventional hand lay-up and compression molding based surface selective dissolution technique ... more A conventional hand lay-up and compression molding based surface selective dissolution technique was utilized to prepare all-cellulose composite (ACC) laminates with varying dissolution times, while lyocell fabric and ionic liquid (1-butyl-3-methyl imidazolium chloride) were used as raw materials. The density of composites increased with increasing dissolution time due to reduction in porosity and formation of more compact composite structure. The tensile strength of the composites increased up to 2h dissolution time and reduced slightly for higher dissolution time. However, Young's modulus of the composites increased significantly, with increasing dissolution time. Water-absorbency at the surface of ACCs also reduced significantly with increasing dissolution time during preparation of ACCs, imparting slight hydrophobicity in the ACC-laminates prepared by using 2h or more dissolution time. The contact angle of the composites produced with 4h dissolution time was about 76.3° and complete absorption of the water droplet took almost 24 minutes. Such high contact angle was obtained due to a change in chemical as well as crystallographic structure of cellulose as analyzed by ATR-FTIR and solid-state 13 C NMR, which was further supported by WAXD, TGA and DTG analysis. A different trend was observed for water and oil absorbency of ACCs based on their absorption mechanism.

A comparative study on lyocell-fabric based all-cellulose composite laminates produced by different processes

Cellulose, Dec 1, 2016

Lyocell-fabric based all-cellulose composite (ACC) laminates were produced using a compression mo... more Lyocell-fabric based all-cellulose composite (ACC) laminates were produced using a compression molding technique by four different routes using ionic liquid (1-butyl-3-methylimidazolium chloride) as solvent. Process I to Process III were used to produce cross-plied ACC laminates while unidirectional ACC laminates were produced by Process IV. The microstructures of the laminates were analyzed on the basis of SEM images and percentage void content. The relations between microstructure and mechanical properties of ACCs were studied on the basis of effect of dissolution time and different process techniques. The tensile and flexural properties of lyocell-ACCs manufactured through the present routes were also compared with conventional biocomposites. In all processes, longer dissolution times resulted in more reduction of internal void content as well as improved microstructure and properties. Compared to Process I, slightly better mechanical properties were achieved by Process II and Process III. An important improvement was observed in tensile and flexural properties for the unidirectional ACC produced using Process IV. The ACC-laminate prepared by Process III with 2 h dissolution time showed the highest inter-laminar adhesion strength (2.15 N/mm). The best tensile strength obtained was 102.6 MPa for the sample produced by Process IV with 1 h dissolution time. ACC-laminate prepared by Process IV with 2 h dissolution time showed the highest flexural strength, flexural modulus and Young's modulus which were 178.3 MPa, 11 and 4.2 GPa, respectively. These mechanical properties are better than those of most conventional biocomposites.

Studies on the dyeability and dyeing mechanism of polyurethane/clay nanocomposite filaments with acid, basic and reactive dyes

Coloration Technology, Feb 20, 2018

Polyurethane/clay nanocomposite (PUCN) filaments were spun by the dry-jet-wet spinning method. To... more Polyurethane/clay nanocomposite (PUCN) filaments were spun by the dry-jet-wet spinning method. To prepare the PUCN filaments, 0.25, 0.50 and 1% of nanoclay on the weight of polyurethane were incorporated in the polyurethane dope. The interaction between clay and polyurethane was analysed by attenuated total reflectance-Fourier Transform-infrared (ATR-FTIR) spectroscopy. The structure and morphology of the PUCN filaments were analysed by wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). Both the neat polyurethane and the PUCN filaments were dyed with different acid, basic and reactive dyes. The neat polyurethane filaments exhibited poor dyeability with all three classes of dyes. By contrast, the PUCN filaments showed a significantly higher dye uptake with all of the dyes used. Furthermore, the dye uptake increased significantly as the percentage of clay in the filaments increased, as indicated by the increase in the K/S values of the dyed filaments. The dyeing mechanism with all three dyes, as well as the increased dyeability of the PUNC filaments in comparison to those of the neat polyurethane filaments, was discussed.

Calcination of UV shielding nanopowder and its effect on weather resistance property of polyurethane nanocomposite films

Journal of Materials Science, Jun 20, 2019

In this study, the synergistic effect of ZnO nanoparticles in combination with two different crys... more In this study, the synergistic effect of ZnO nanoparticles in combination with two different crystal phases of TiO 2 nanoparticles on improving weather resistance property of polyurethane (PU) film has been studied. The UV shielding nanopowder containing TiO 2 and ZnO nanoparticles was calcinated at varying conditions, and the process was optimized to obtain the desired crystal structure. After calcination, the change in crystal phase, crystal size, inter-planer distance in crystal and particle size was characterized using XRD, TEM and particle size analyzer, while chemical changes were analyzed by FTIR and EDX. The as-received as well as calcinated UV shielding nanopowders (1-5 wt%) were incorporated in PU matrix by melt mixing in a twin-screw extruder, and the extrudate nanocomposites were used to make films. The neat PU and nanocomposite films were exposed in accelerated artificial weathering for 300 h, while the films were analyzed at a 100-h interval. The physical and chemical changes of exposed film surface were analyzed by SEM, AFM and FTIR. The UV protection factor (UPF) of both types of PU nanocomposite films increased with increased loading of nanoparticles, although the UPF values were slightly lower for calcinated UV shielding nanopowder-based PU nanocomposite films. The calcinated UV shielding nanopowder showed good potential in improving weather resistance of PU nanocomposite films in term of-(1) lower change in surface morphology and surface chemistry and (2) better retention in tensile properties after exposure in accelerated artificial weathering. The synergistic effect of ZnO nanoparticle and rutile phase enriched TiO 2 nanoparticles in calcinated UV shielding nanopowder enhanced the weather resistance of PU films significantly.

Polyurethane nanocomposite based gas barrier films, membranes and coatings: A review on synthesis, characterization and potential applications

Progress in Materials Science, Aug 1, 2018

Polyurethane (PU) and its nanocomposites based gas barrier films and coatings have established a ... more Polyurethane (PU) and its nanocomposites based gas barrier films and coatings have established a distinctive position among various technologically important materials due to their large-scale potential applications. This review aims at highlighting the gas barrier property of polyurethane nanocomposite (PUNC) based films, membranes and coatings containing platelet-shaped fillers such as clays and graphene in PU matrix. The other fillers such as CNT, POSS, metal nanoparticles and nanocellulose have also been reviewed for their contribution in improving gas barrier property of polymers. The probable transport-mechanism of small gas molecules through PU and PUNCs have been discussed. There is also a discussion on basic PU-chemistry and effect of structure and morphology of PU on its gas barrier property. Various factors which influence the gas permeability through PU and PUNC films and coatings have been scrutinized. Some aspects of improving the gas barrier property of PUNCs have also been discussed. An emphasis is given on various proposed models for prediction of gas permeability through polymer nanocomposites. It also reviews the existing literature related to modeling and prediction of gas permeability of different PUNC membranes, films and coatings. Finally, special attention has been paid to the potential industrial applications of PUNC based films and coatings.

Single-Polymer Composites from Polyesters

Nano-ceria and nano-zirconia reinforced polyurethane nanocomposite-based coated textiles with enhanced weather resistance

Progress in Organic Coatings, Apr 1, 2022

Advances in Nanotechnology Based Functional, Smart and Intelligent Textiles: A Review

Elsevier eBooks, 2019

High performance 2D MXene based conducting polymer hybrids: synthesis to emerging applications

Journal of Materials Chemistry C, 2021

This review highlights the recent advances in MXene-conducting polymer hybrids for wearable elect... more

Polyurethane/functionalized-graphene nanocomposite films with enhanced weather resistance and gas barrier properties

Composites Part B-engineering, Nov 1, 2019

This study explores the potential of graphene for improvement of weather resistance and helium ga... more This study explores the potential of graphene for improvement of weather resistance and helium gas barrier properties of thermoplastic polyurethane (PU) film. PU/functionalized-graphene nanocomposite (PGN) films were produced by solution master-batching and subsequent melt mixing, followed by compression molding, with varying concentrations (0-3 wt%) of graphene, which resulted in uniform dispersion and partial exfoliation of graphene-sheets in PU matrix. The helium gas barrier of nanocomposite films improved gradually with increasing graphene concentration, showing about 30% reduction in gas-permeability at 3 wt% grapheneloading. The tensile strength and stiffness of the nanocomposite films also increased significantly with increasing concentration of graphene. The prepared PGN films were exposed to accelerated artificial weathering conditions up to 300 h. Due to excellent UV absorption capability of graphene, the weather resistance of nanocomposite films improved significantly, resulting in lower photooxidative and carbonyl index. Best weather resistance in terms of retention in tensile and gas barrier properties was obtained with 2-3 wt% of graphene.

Green Solvent Processed Cellulose/Graphene Oxide Nanocomposite Films with Superior Mechanical, Thermal, and Ultraviolet Shielding Properties

ACS Applied Materials & Interfaces, Dec 16, 2019

This study reports for the first time, a green process to fabricate Lyocell fiber and graphene ox... more This study reports for the first time, a green process to fabricate Lyocell fiber and graphene oxide (GO) based novel cellulose/graphene oxide nanocomposite (CGN) flexible films for ultraviolet (UV) shielding applications. Polyethelene glycol (PEG) mediated solvent system was utilized to make CGN films via solution casting route. To improve the dispersion of GO sheets in cellulosic matrix, a reactive interface was formed in-between cellulose and oxygenic functionalized groups of GO sheets via crosslinking them with epichlorohydrin (ECH). The addition of GO sheets in cellulose matrix leads to the synergistic changes, which were observed in the structure and surface morphology of CGN nanocomposite films. Enhanced dispersion of GO sheets in CGN films was observed in morphological investigations which is attributed to the adequate cellulose-GO interaction by hydrogen bonding, led to significant enhancement in mechanical and thermal properties. The tensile strength and Young's modulus of CGN films with 2wt% GO loading (CGN2) increased to 89 MPa and 4.3 GPa from 55.6 MPa and 2.1 GPa, respectively as compared to neat cellulosic film. Additionally, the CGN films exhibited remarkable UV shielding capability which increased with GO loading in cellulose matrix. The CGN2 film (2wt% GO loading) possessed outstanding absorbance in the wavelength range of 280 nm to 400 nm, showed almost complete shielding (~99%) of UV rays both in UV-B and UV-A region. Moreover, the ultraviolet protection factor (UPF) of CGN2 film demonstrated more than eighty fold increase in comparison to neat cellulose (NC) film. The obtained CGN nanocomposite film has a high potential for applications in the field of UV protection.

Effect of organoclay-type and clay-polyurethane interaction chemistry for tuning the morphology, gas barrier and mechanical properties of clay/polyurethane nanocomposites

Applied Clay Science, Sep 1, 2018

Organo-modified montmorillonite (Mt) and bentonite reinforced clay/polyurethane nanocomposite (CP... more Organo-modified montmorillonite (Mt) and bentonite reinforced clay/polyurethane nanocomposite (CPN) films were produced by master-batch based melt-mixing route, followed by compression molding. A novel route for preparation of master-batch by solution mixing was explored by using sonication and high-speed stirring. It was found that master-batch prepared by solvent mixing route resulted in good dispersion of clay-platelets in masterbatch and finally in CPN. The concentration of both organoclays was varied from 1 to 5 wt% in final CPN, which were prepared by melt-mixing of master-batch and neat polyurethane (PU) in a twin-screw extruder. The presence of hydroxyl group in the clay-modifier of Mt, attributed to nearly exfoliated structure up to 3 wt % due to improved interaction by hydrogen bonding with ether groups or urethane linkages. Whereas, organomodified bentonite showed partially intercalated and flocculated morphology, due to the absence of any polar group in the clay-modifier. As a consequence, Mt/PU nanocomposites showed much better mechanical and gas barrier properties in comparison to bentonite/PU nanocomposites. Moreover, a significant reduction in helium gas permeability and improvement in mechanical (tensile and tear) properties were observed for CPN produced with both organoclays in comparison to neat PU. At lower volume fraction of organoclays, a good correlation was obtained between gas permeability values determined experimentally and predicted by two different mathematical models.

Effect of pressure on structure and properties of lyocell fabric-based all-cellulose composite laminates

Journal of The Textile Institute, Jul 20, 2016

In this work, all-cellulose composite (ACC) laminates were manufactured from lyocell fabric using... more In this work, all-cellulose composite (ACC) laminates were manufactured from lyocell fabric using a simple hand lay-up and compression molding-based surface-selective dissolution technique. In dissolution step, temperature and dissolution time were fixed and pressure varied. Subsequently, the dissolved cellulose was regenerated via solvent exchange and then dried by hot-pressing. The microstructures of ACC laminates were analyzed by scanning electron microscope micrographs and measuring void content. Optimum microstructure and mechanical properties were obtained with a pressure of 1 MPa, but slightly deteriorated with further increase in pressure. The highest tensile strength and modulus achieved were 44.24 ± 2.2 MPa and 1.78 ± 0.14 GPa, respectively, for ACC-3. Best flexural strength and modulus obtained were 48.95 ± 2.87 MPa and 0.96 ± 0.21 GPa, respectively, for the same sample. The T-peel strength of ACC-3 also was very high, 2.78 ± 0.34 MPa. Application of pressure during drying had a great role on controlling shrinkage and internal voids in ACC laminates.

Cellulose based flexible and wearable sensors for health monitoring

Materials Advances

Cellulose is one of the greatest bio-resourced materials. In this review, the excellent advanceme... more Cellulose is one of the greatest bio-resourced materials. In this review, the excellent advancement of cellulose-based sensors for wearable real-time health monitoring are described. In addition, the emerging prospects and challenges of cellulose based flexible devices within this fields are also presented.

Cellulose based flexible and wearable sensors for health monitoring

Materials advances, 2022

Recently, with the advancement of materials science and manufacturing methods, researchers have i... more Recently, with the advancement of materials science and manufacturing methods, researchers have introduced many new and advanced materials for wearable sensors. In particular, incredible advancement has been made in flexible strain sensors for their application in wearable health monitoring, soft-robotics, human-machine interactions (HMI), and so forth. Cellulose, the most abundant natural biopolymer, is one of the most viable substrates for strain and pressure sensors, mainly due to its biocompatibility and biodegradability along with many other useful features. Cellulose is available in various forms including fibers, nanocrystals, and nanofibers, and different techniques are used to fabricate these into hydrogels, aerogels, films, paper, fabrics, and eventually into sensors. An overview of the fabrication, sensing performance, and applications of cellulose-based flexible physiological sensors has been presented in this review, along with their use in monitoring healthcare activities through different types of strain sensors, pressure sensors and HMIs. It is observed that an appropriate selection of the substrate and functional materials greatly influence the sensing characteristics of these sensors, such as sensitivity, response time, effective strain range, stability under strain/pressure, and hysteresis. The potential for further research on this subject has also been highlighted, along with the recent trends in using flexible sensors for health-monitoring.

A synergy of atmospheric plasma and UV-additive incorporated PU and styrene-isoprene-styrene adhesive for improving inter-layer adhesion in PVF/Fabric/BOPET laminate for aerostat envelope

Composites Part A-applied Science and Manufacturing, Oct 1, 2023

1 Introduction to functional, smart, and intelligent textiles: perspectives and potential applications

De Gruyter eBooks, Mar 20, 2023

Introduction to LTA Systems

CRC Press eBooks, Feb 3, 2022

Modelling for Performance Analysis of Aerostats/Airships

CRC Press eBooks, Feb 3, 2022

Applications, Current Difficulties, and Future Scope of Single-Polymer Composites

All-cellulose composite laminates with low moisture and water sensitivity

Polymer, Apr 1, 2018

A conventional hand lay-up and compression molding based surface selective dissolution technique ... more A conventional hand lay-up and compression molding based surface selective dissolution technique was utilized to prepare all-cellulose composite (ACC) laminates with varying dissolution times, while lyocell fabric and ionic liquid (1-butyl-3-methyl imidazolium chloride) were used as raw materials. The density of composites increased with increasing dissolution time due to reduction in porosity and formation of more compact composite structure. The tensile strength of the composites increased up to 2h dissolution time and reduced slightly for higher dissolution time. However, Young's modulus of the composites increased significantly, with increasing dissolution time. Water-absorbency at the surface of ACCs also reduced significantly with increasing dissolution time during preparation of ACCs, imparting slight hydrophobicity in the ACC-laminates prepared by using 2h or more dissolution time. The contact angle of the composites produced with 4h dissolution time was about 76.3° and complete absorption of the water droplet took almost 24 minutes. Such high contact angle was obtained due to a change in chemical as well as crystallographic structure of cellulose as analyzed by ATR-FTIR and solid-state 13 C NMR, which was further supported by WAXD, TGA and DTG analysis. A different trend was observed for water and oil absorbency of ACCs based on their absorption mechanism.

A comparative study on lyocell-fabric based all-cellulose composite laminates produced by different processes

Cellulose, Dec 1, 2016

Lyocell-fabric based all-cellulose composite (ACC) laminates were produced using a compression mo... more Lyocell-fabric based all-cellulose composite (ACC) laminates were produced using a compression molding technique by four different routes using ionic liquid (1-butyl-3-methylimidazolium chloride) as solvent. Process I to Process III were used to produce cross-plied ACC laminates while unidirectional ACC laminates were produced by Process IV. The microstructures of the laminates were analyzed on the basis of SEM images and percentage void content. The relations between microstructure and mechanical properties of ACCs were studied on the basis of effect of dissolution time and different process techniques. The tensile and flexural properties of lyocell-ACCs manufactured through the present routes were also compared with conventional biocomposites. In all processes, longer dissolution times resulted in more reduction of internal void content as well as improved microstructure and properties. Compared to Process I, slightly better mechanical properties were achieved by Process II and Process III. An important improvement was observed in tensile and flexural properties for the unidirectional ACC produced using Process IV. The ACC-laminate prepared by Process III with 2 h dissolution time showed the highest inter-laminar adhesion strength (2.15 N/mm). The best tensile strength obtained was 102.6 MPa for the sample produced by Process IV with 1 h dissolution time. ACC-laminate prepared by Process IV with 2 h dissolution time showed the highest flexural strength, flexural modulus and Young's modulus which were 178.3 MPa, 11 and 4.2 GPa, respectively. These mechanical properties are better than those of most conventional biocomposites.

Studies on the dyeability and dyeing mechanism of polyurethane/clay nanocomposite filaments with acid, basic and reactive dyes

Coloration Technology, Feb 20, 2018

Polyurethane/clay nanocomposite (PUCN) filaments were spun by the dry-jet-wet spinning method. To... more Polyurethane/clay nanocomposite (PUCN) filaments were spun by the dry-jet-wet spinning method. To prepare the PUCN filaments, 0.25, 0.50 and 1% of nanoclay on the weight of polyurethane were incorporated in the polyurethane dope. The interaction between clay and polyurethane was analysed by attenuated total reflectance-Fourier Transform-infrared (ATR-FTIR) spectroscopy. The structure and morphology of the PUCN filaments were analysed by wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). Both the neat polyurethane and the PUCN filaments were dyed with different acid, basic and reactive dyes. The neat polyurethane filaments exhibited poor dyeability with all three classes of dyes. By contrast, the PUCN filaments showed a significantly higher dye uptake with all of the dyes used. Furthermore, the dye uptake increased significantly as the percentage of clay in the filaments increased, as indicated by the increase in the K/S values of the dyed filaments. The dyeing mechanism with all three dyes, as well as the increased dyeability of the PUNC filaments in comparison to those of the neat polyurethane filaments, was discussed.

Calcination of UV shielding nanopowder and its effect on weather resistance property of polyurethane nanocomposite films

Journal of Materials Science, Jun 20, 2019

In this study, the synergistic effect of ZnO nanoparticles in combination with two different crys... more In this study, the synergistic effect of ZnO nanoparticles in combination with two different crystal phases of TiO 2 nanoparticles on improving weather resistance property of polyurethane (PU) film has been studied. The UV shielding nanopowder containing TiO 2 and ZnO nanoparticles was calcinated at varying conditions, and the process was optimized to obtain the desired crystal structure. After calcination, the change in crystal phase, crystal size, inter-planer distance in crystal and particle size was characterized using XRD, TEM and particle size analyzer, while chemical changes were analyzed by FTIR and EDX. The as-received as well as calcinated UV shielding nanopowders (1-5 wt%) were incorporated in PU matrix by melt mixing in a twin-screw extruder, and the extrudate nanocomposites were used to make films. The neat PU and nanocomposite films were exposed in accelerated artificial weathering for 300 h, while the films were analyzed at a 100-h interval. The physical and chemical changes of exposed film surface were analyzed by SEM, AFM and FTIR. The UV protection factor (UPF) of both types of PU nanocomposite films increased with increased loading of nanoparticles, although the UPF values were slightly lower for calcinated UV shielding nanopowder-based PU nanocomposite films. The calcinated UV shielding nanopowder showed good potential in improving weather resistance of PU nanocomposite films in term of-(1) lower change in surface morphology and surface chemistry and (2) better retention in tensile properties after exposure in accelerated artificial weathering. The synergistic effect of ZnO nanoparticle and rutile phase enriched TiO 2 nanoparticles in calcinated UV shielding nanopowder enhanced the weather resistance of PU films significantly.

Polyurethane nanocomposite based gas barrier films, membranes and coatings: A review on synthesis, characterization and potential applications

Progress in Materials Science, Aug 1, 2018

Polyurethane (PU) and its nanocomposites based gas barrier films and coatings have established a ... more Polyurethane (PU) and its nanocomposites based gas barrier films and coatings have established a distinctive position among various technologically important materials due to their large-scale potential applications. This review aims at highlighting the gas barrier property of polyurethane nanocomposite (PUNC) based films, membranes and coatings containing platelet-shaped fillers such as clays and graphene in PU matrix. The other fillers such as CNT, POSS, metal nanoparticles and nanocellulose have also been reviewed for their contribution in improving gas barrier property of polymers. The probable transport-mechanism of small gas molecules through PU and PUNCs have been discussed. There is also a discussion on basic PU-chemistry and effect of structure and morphology of PU on its gas barrier property. Various factors which influence the gas permeability through PU and PUNC films and coatings have been scrutinized. Some aspects of improving the gas barrier property of PUNCs have also been discussed. An emphasis is given on various proposed models for prediction of gas permeability through polymer nanocomposites. It also reviews the existing literature related to modeling and prediction of gas permeability of different PUNC membranes, films and coatings. Finally, special attention has been paid to the potential industrial applications of PUNC based films and coatings.

Single-Polymer Composites from Polyesters

Nano-ceria and nano-zirconia reinforced polyurethane nanocomposite-based coated textiles with enhanced weather resistance

Progress in Organic Coatings, Apr 1, 2022

Advances in Nanotechnology Based Functional, Smart and Intelligent Textiles: A Review

Elsevier eBooks, 2019

High performance 2D MXene based conducting polymer hybrids: synthesis to emerging applications

Journal of Materials Chemistry C, 2021

This review highlights the recent advances in MXene-conducting polymer hybrids for wearable elect... more

Polyurethane/functionalized-graphene nanocomposite films with enhanced weather resistance and gas barrier properties

Composites Part B-engineering, Nov 1, 2019

This study explores the potential of graphene for improvement of weather resistance and helium ga... more This study explores the potential of graphene for improvement of weather resistance and helium gas barrier properties of thermoplastic polyurethane (PU) film. PU/functionalized-graphene nanocomposite (PGN) films were produced by solution master-batching and subsequent melt mixing, followed by compression molding, with varying concentrations (0-3 wt%) of graphene, which resulted in uniform dispersion and partial exfoliation of graphene-sheets in PU matrix. The helium gas barrier of nanocomposite films improved gradually with increasing graphene concentration, showing about 30% reduction in gas-permeability at 3 wt% grapheneloading. The tensile strength and stiffness of the nanocomposite films also increased significantly with increasing concentration of graphene. The prepared PGN films were exposed to accelerated artificial weathering conditions up to 300 h. Due to excellent UV absorption capability of graphene, the weather resistance of nanocomposite films improved significantly, resulting in lower photooxidative and carbonyl index. Best weather resistance in terms of retention in tensile and gas barrier properties was obtained with 2-3 wt% of graphene.

Green Solvent Processed Cellulose/Graphene Oxide Nanocomposite Films with Superior Mechanical, Thermal, and Ultraviolet Shielding Properties

ACS Applied Materials & Interfaces, Dec 16, 2019

This study reports for the first time, a green process to fabricate Lyocell fiber and graphene ox... more This study reports for the first time, a green process to fabricate Lyocell fiber and graphene oxide (GO) based novel cellulose/graphene oxide nanocomposite (CGN) flexible films for ultraviolet (UV) shielding applications. Polyethelene glycol (PEG) mediated solvent system was utilized to make CGN films via solution casting route. To improve the dispersion of GO sheets in cellulosic matrix, a reactive interface was formed in-between cellulose and oxygenic functionalized groups of GO sheets via crosslinking them with epichlorohydrin (ECH). The addition of GO sheets in cellulose matrix leads to the synergistic changes, which were observed in the structure and surface morphology of CGN nanocomposite films. Enhanced dispersion of GO sheets in CGN films was observed in morphological investigations which is attributed to the adequate cellulose-GO interaction by hydrogen bonding, led to significant enhancement in mechanical and thermal properties. The tensile strength and Young's modulus of CGN films with 2wt% GO loading (CGN2) increased to 89 MPa and 4.3 GPa from 55.6 MPa and 2.1 GPa, respectively as compared to neat cellulosic film. Additionally, the CGN films exhibited remarkable UV shielding capability which increased with GO loading in cellulose matrix. The CGN2 film (2wt% GO loading) possessed outstanding absorbance in the wavelength range of 280 nm to 400 nm, showed almost complete shielding (~99%) of UV rays both in UV-B and UV-A region. Moreover, the ultraviolet protection factor (UPF) of CGN2 film demonstrated more than eighty fold increase in comparison to neat cellulose (NC) film. The obtained CGN nanocomposite film has a high potential for applications in the field of UV protection.

Effect of organoclay-type and clay-polyurethane interaction chemistry for tuning the morphology, gas barrier and mechanical properties of clay/polyurethane nanocomposites

Applied Clay Science, Sep 1, 2018

Organo-modified montmorillonite (Mt) and bentonite reinforced clay/polyurethane nanocomposite (CP... more Organo-modified montmorillonite (Mt) and bentonite reinforced clay/polyurethane nanocomposite (CPN) films were produced by master-batch based melt-mixing route, followed by compression molding. A novel route for preparation of master-batch by solution mixing was explored by using sonication and high-speed stirring. It was found that master-batch prepared by solvent mixing route resulted in good dispersion of clay-platelets in masterbatch and finally in CPN. The concentration of both organoclays was varied from 1 to 5 wt% in final CPN, which were prepared by melt-mixing of master-batch and neat polyurethane (PU) in a twin-screw extruder. The presence of hydroxyl group in the clay-modifier of Mt, attributed to nearly exfoliated structure up to 3 wt % due to improved interaction by hydrogen bonding with ether groups or urethane linkages. Whereas, organomodified bentonite showed partially intercalated and flocculated morphology, due to the absence of any polar group in the clay-modifier. As a consequence, Mt/PU nanocomposites showed much better mechanical and gas barrier properties in comparison to bentonite/PU nanocomposites. Moreover, a significant reduction in helium gas permeability and improvement in mechanical (tensile and tear) properties were observed for CPN produced with both organoclays in comparison to neat PU. At lower volume fraction of organoclays, a good correlation was obtained between gas permeability values determined experimentally and predicted by two different mathematical models.