| 1. |
- Bakhshpour, Monireh, et al.
(författare)
-
Molecular Imprinted Nanocomposites for Green Chemistry
- 2021
-
Ingår i: Green Composites. - Singapore : Springer Singapore. - 2524-5392 .- 2524-5384. - 9789811596421 - 9789811596438 ; , s. 571-598
-
Bokkapitel (refereegranskat)abstract
- Nanocomposite materials which are considered ‘green’ refer to non-toxic, biodegradable and renewable nanocomposites. The reasons of preferring green nanocomposites much more could be explained by environmental friendly, fully degradability, renewability and sustainability in all respects. Furthermore, the production of green nanocomposites should not be based on toxic chemicals. When their functions are definitely completed, they can be easily destroyed without harming the environment. The challenge with green composites arises from the difficulty of producing green nano-polymers to be applied as matrices in the construction of basic composites. Molecularly imprinted polymers (MIPs) have been extensively synthesized from various functional monomers. In green chemistry principles, elimination of toxic reagents in the analytical process, the use of reagents from a renewable source are performed. To date, there are some publications pointing out the utilization of harmless chemicals for the design of MIPs. It has been a great opportunity that a novel research area has emerged considering the combination of environmentally friendly reagents and traditional organic monomers for MIP synthesis. In this chapter, the recent advances in the field of both green synthesis and green applications by focusing the molecular imprinting technology are summarized, and the developments in green strategies are highlighted.
|
|
| 2. |
- Deepa, B., et al.
(författare)
-
Utilization of various lignocellulosic biomass for the production of nanocellulose : a comparative study
- 2015
-
Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 22:2, s. 1075-1090
-
Tidskriftsartikel (refereegranskat)abstract
- Nanocellulose was successfully extracted from five different lignocellulosic biomass sources viz. banana rachis, sisal, kapok, pineapple leaf and coir using a combination of chemical treatments such as alkaline treatment, bleaching and acid hydrolysis. The shape, size and surface properties of the nanocellulose generally depend on the source and hydrolysis conditions. A comparative study of the fundamental properties of raw material, bleached and nanocellulose was carried out by means of Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, transmission electron microscopy, birefringence, X-ray diffraction, inverse gas chromatography and thermogravimetric analysis. Through the characterization of the nanocellulose obtained from different sources, the isolated nanocellulose showed an average diameter in the range of 10–25 nm, high crystallinity, high thermal stability and a great potential to be used with acid coupling agents due to a predominantly basic surface. This work provides an insight into the effective utilization of a variety of plant biomass as a potential source for nanocellulose extraction.
|
|
| 3. |
- Deepalakshmi, P, et al.
(författare)
-
Advances in elastomers : Their composites and nanocomposites: State of art, new challenges and opportunities
- 2013
-
Ingår i: Advances in elastomers II. - Berlin : Encyclopedia of Global Archaeology/Springer Verlag. - 9783642209277 - 9783642209284 ; , s. 1-9
-
Bokkapitel (refereegranskat)abstract
- The field of elastomers, their composites and nanocomposites has gained a lot of interest in recent years. These composite materials have great significance both from the fundamental and application point of view. Since this field is growing at a faster rate, it is always necessary to address the structure, properties and applicability of such materials. The present chapter gives a brief account on various elastomer systems, their composites and nanocomposites. Various topics such as elastomer based macrocomposites, nanocomposites, interphase modification, compatiblisation of rubber based nanocomposites, fully green elastomer nanocomposites, elastomeric micro and nanocomposites for tyre applications, elastomer based bionanocomposites, bio-medical applications of elastomeric composites and nanocomposites have been very briefly discussed. Finally the applications, new challenges and opportunities of these composites and nanocomposites are also discussed.
|
|
| 4. |
- Gopakumar, Deepu A., et al.
(författare)
-
Nanocellulose-Based Membranes for Water Purification
- 2019
-
Ingår i: Nanoscale Materials in Water Purification. - 9780128139271 ; , s. 59-85
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Scarcity and contamination of worldwide drinking water demand advanced, effective water purification methodologies. Eliminating numerous contaminants, such as heavy metals, toxic textile dyes, pesticides, oil, and other industrial, as well as agricultural, wastes, from water has become a serious concern because of their adverse effects on human health and the ecosystem. Recently, developments in nanoscience and nanotechnology propose that several of the present problems relating to water quality could be greatly reduced by using nanomaterials because of their good adsorption efficiency, higher surface area, and greater active sites for interaction with contaminants in water. In this context, nanocellulose is the most abundant and renewable polymer available globally and consists of repeating β-d-glucopyranose units covalently linked through acetal functions between the hydroxyl groups of C4 and C1 carbon atoms that provide it chirality and reactivity properties. Nanocellulose is a fascinating material for practical applications because it is cost-effective, is renewable, and can be handled at huge scale using conventional wood industry techniques. Nanocellulose is a valuable filtration material because it is affordable, sustainable, inert, and stable at a broad range of pH/ionic strength. Moreover, the abundant availability of the surface hydroxyl groups on the nanocellulose facilitates various surface chemistries that can be explored for targeting various contaminants in water. This chapter covers the recent developments and literature of nanocellulose in the field of water purification.
|
|
| 5. |
- Hasan, M., et al.
(författare)
-
Robust superhydrophobic cellulose nanofiber aerogel for multifunctional environmental applications
- 2019
-
Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 11:3
-
Tidskriftsartikel (refereegranskat)abstract
- The fabrication of superadsorbent for dye adsorption is a hot research area at present. However, the development of low-cost and highly efficient superadsorbents against toxic textile dyes is still a big challenge. Here, we fabricated hydrophobic cellulose nanofiber aerogels from cellulose nanofibers through an eco-friendly silanization reaction in liquid phase, which is an extremely efficient, rapid, cheap, and environmentally friendly procedure. Moreover, the demonstrated eco-friendly silanization technique is easy to commercialize at the industrial level. Most of the works that have reported on the hydrophobic cellulose nanofiber aerogels explored their use for the elimination of oil from water. The key novelty of the present work is that the demonstrated hydrophobic cellulose nanofibers aerogels could serve as superadsorbents against toxic textile dyes such as crystal violet dye from water and insulating materials for building applications. Here, we make use of the possible hydrophobic interactions between silane-modified cellulose nanofiber aerogel and crystal violet dye for the removal of the crystal violet dye from water. With a 10 mg/L of crystal violet (CV) aqueous solution, the silane-modified cellulose nanofiber aerogel showed a high adsorption capacity value of 150 mg/g of the aerogel. The reason for this adsorption value was due to the short-range hydrophobic interaction between the silane-modified cellulose nanofiber aerogel and the hydrophobic domains in crystal violet dye molecules. Additionally, the fabricated silane-modified cellulose nanofiber hydrophobic aerogels exhibited a lower thermal conductivity value of 0.037 W·m -1 K -1 , which was comparable to and lower than the commercial insulators such as mineral wools (0.040 W·m -1 K -1 ) and polystyrene foams (0.035 W·m -1 K -1 ). We firmly believe that the demonstrated silane-modified cellulose nanofiber aerogel could yield an eco-friendly adsorbent that is agreeable to adsorbing toxic crystal violet dyes from water as well as active building thermal insulators.
|
|
| 6. |
- Jose, Jiya, et al.
(författare)
-
Fabrication and functionalization of 3D-printed soft and hard scaffolds with growth factors for enhanced bioactivity
- 2020
-
Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 10:62, s. 37928-37937
-
Tidskriftsartikel (refereegranskat)abstract
- Strategies to improve the acceptance of scaffolds by the body is crucial in tissue engineering (TE) which requires tailoring of the pore structure, mechanical properties and surface characteristics of the scaffolds. In the current study we used a 3-dimensional (3D) printing technique to tailor the pore structure and mechanical properties of (i) nanocellulose based hydrogel scaffolds for soft tissue engineering and (ii) poly lactic acid (PLA) based scaffolds for hard tissue engineering in combination with surface treatment by protein conjugation for tuning the scaffold bioactivity. Dopamine coating of the scaffolds enhanced the hydrophilicity and their capability to bind bioactive molecules such as fibroblast growth factor (FGF-18) for soft TE scaffolds and arginyl glycyl aspartic acid (RGD) peptide for hard TE scaffolds, which was confirmed using MALDI-TOFs. This functionalization approach enhanced the performance of the scaffolds and provided antimicrobial activity indicating that these scaffolds can be used for cartilage or bone regeneration applications. Blood compatibility studies revealed that both the materials were compatible with human red blood cells. Significant enhancement of cell attachment and proliferation confirmed the bioactivity of growth factor functionalized 3D printed soft and hard tissues. This approach of combining 3D printing with biological tuning of the interface is expected to significantly advance the development of biomedical materials related to soft and hard tissue engineering.
|
|
| 7. |
- Mathew, Aji P., et al.
(författare)
-
Effect of initiating system, blend ratio and crosslink density on the mechanical properties and failure topography of nano-structured full-interpenetrating polymer networks from natural rubber and polystyrene
- 2001
-
Ingår i: European Polymer Journal. - 0014-3057 .- 1873-1945. ; 37:9, s. 1921-1934
-
Tidskriftsartikel (refereegranskat)abstract
- The mechanical performance of full-interpenetrating polymer networks (IPNs) based on natural rubber/polystyrene (NR/PS) system has been studied in detail. The IPNs were prepared using different initiators viz., benzoyl peroxide (BPO), azo-bis-isobutyronitrile (AIBN), and dicumyl peroxide (DCP) and the effect of initiating systems on the properties was studied. It was observed that in all cases the IPNs initiated using DCP showed a superior property compared to BPO and AIBN initiated ones. The crosslink density of the IPN was varied by varying the percent of divinyl benzene (crosslinking agent of PS) and the effect of crosslink density on the properties has been studied. The stress-strain behaviour, tensile strength, Young's modulus, elongation at break, tear strength, tension set and tensile set were determined. The effects of strain rate on tensile properties were analysed. The studies on the morphology using scanning electron microscopy showed an increase in phase mixing on increasing the PS content and PS crosslinking. However, high level of PS content and PS crosslinking lead to a decrease in phase mixing. The morphology studies using TEM revealed the interesting fact that NR/PS IPN system was nano-structured. The fracture surfaces of tensile and tear specimens were studied using scanning electron microscopy, to get a clear picture of the mechanism of failure.
|
|
| 8. |
- Mathew, Aji P., et al.
(författare)
-
Izod impact behavior of natural rubber/polystyrene interpenetrating polymer networks
- 2001
-
Ingår i: Materials letters (General ed.). - 0167-577X .- 1873-4979. ; 50:2-3, s. 154-163
-
Tidskriftsartikel (refereegranskat)abstract
- The impact behavior of semi and full interpenetrating polymer networks based on natural rubber (NR) and polystyrene (PS) has been studied with special reference to blend ratio and cross-linking level of PS phase. As the PS cross-linker level increases up to 4% an increase in impact strength values was observed. This behavior was explained based on blend morphology and the fractography. It was also found that in moderately cross-linked IPNs, the blend composition with 70% PS showed maximum impact strength values. At higher cross-linking levels, samples with 60% PS showed maximum impact strength values. The fracture surface morphology satisfactorily explained the nature of failure and impact performance in all cases. Addition of NR to PS has changed the failure mechanism from crazing to shear yielding
|
|
| 9. |
- Mathew, Aji P., et al.
(författare)
-
Studies on the thermal stability of natural rubber/polystyrene interpenetrating polymer networks : thermogravimetric analysis
- 2001
-
Ingår i: Polymer degradation and stability. - 0141-3910 .- 1873-2321. ; 72:3, s. 423-439
-
Tidskriftsartikel (refereegranskat)abstract
- The thermal degradation of natural rubber/polystyrene (NR/PS) interpenetrating polymer networks (IPNs) was studied and the effects of blend ratio, crosslink level and initiating system were analysed. The thermogravimetric analysis (TGA) shows that the IPNs are more stable than the pure components. The full-IPNs have better stability than semi-IPNs which is due to higher entanglement density of full-IPNs. The initial decomposition temperature and temperature for 50% decomposition (T50) increase with increase in concentration and crosslinker level of the plastic phase. The kinetics of degradation were analysed using nine mechanistic equations. The kinetic parameters such as activation energy, Arrhenius parameter and entropy of activation were determined. Thermal ageing studies of the samples were also conducted. The IPNs aged for 72 h at 100°C showed enhanced mechanical strength due to crosslinking on post curing.
|
|
| 10. |
- Mathew, Aji P., et al.
(författare)
-
Transport of aromatic solvents through natural rubber/polystyrene (NR/PS) interpenetrating polymer network membranes
- 2002
-
Ingår i: Journal of Membrane Science. - 0376-7388 .- 1873-3123. ; 20:1-2, s. 213-227
-
Tidskriftsartikel (refereegranskat)abstract
- A series of interpenetrating polymer network membranes have been synthesised from natural rubber and polystyrene by the sequential polymerisation technique. The transport of aromatic hydrocarbons through semi- and full-interpenetrating polymer network membranes (IPNs) have been studied in detail by tracing the solvent uptake up to equilibrium. The sorption was carried out in a series of aromatic solvents viz. benzene, toluene and xylene. The effect of temperature on swelling is studied by carrying out the experiments in toluene in the temperature range of 30-75 °C. The effects of blend ratio, crosslinker content and nature of initiator on the diffusion of various solvents were analysed. It was found that in all cases, the uptake value increased by about 50% as the PS content decreased from 70-30%. The diffusion, sorption and permeation coefficients were evaluated. As the crosslink density was increased, the uptake decreased by 40%. Kinetic and thermodynamic parameters were evaluated from diffusion experiments. The diffusion profiles were compared with theoretical predictions. The influence of swelling on the mechanical performance of the membranes has been investigated by conducting tensile testing of swollen specimens.
|
|
