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Kavita Rastogi Collection
No full textPhotograph of Raji Awasiiy Vidyalay. Jauljibi Students from classes 5-8 were gathered for an essay competition. The essay competition was organized by Rastogi and Jana Fortier with the permission of the principal of the school, Shri Sanjay Khanka
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Kavita Rastogi Collection
No full textPhotograph of the essay competition with 9 total student submissions. The essay competition was organized by Rastogi and Jana Fortier with the permission of the principal of the school, Shri Sanjay Khanka
Scientometric portrait of Ram Gopal Rastogi
Get PDFPublication productivity of Indian scientist (R.G. Rastogi) has been documented.
Scientometric analysis of 312 papers by Ram Gopal Rastogi published during 1954 to 1992 in various domains: (a) Luni -solar activity and quiet -time E & F- region (57); (b) Equatorial electric field and low and mid latitude iof:osphere (78); (c) Ionospheric E- region irregularities (19); (dj Ionospheric F- region irregularities (32); and (e) Magnetic disturbance effects on the equatorial low and mid latitude ionosphere (23) were analysed. Interdomainery contents and of the number of papers: a+b were 36; b+c and b+d were 20 each; b+e were 16;. c+e were 5; a+e were 3; d+e were 2; and a+d had only one publication. Highest collaborations were with H. Chandra (61), M.R. Deshpande (42), and G. Sethia (19) out of his total 97 collaborators. His highest productivity was during 1978 with 28 papers followed by 19 papers during 1977. The core journals preferred by him for publishing papers were: Indian Journal of Radio & Space Physics, India, and Journal of Atomic & Terrestrial Physics, UK (59 each), followed by Proceedings of the Indian Academy of Sciences, India (34). Most prolific title keywords with their frequencies were: Ionosphere (92); Equatorial (61); F-region (53); Equatorial electrojet region (40), and Magnetic equator (30)
Molecular organization in homogeneous polyethylene copolymers at elevated pressure-temperature
Get PDFAfrindian Fictions: Diaspora, Race, and National Desire in South Africa
No full textIn the first published book-length study of Indian fiction in South Africa, Pallavi Rastogi demonstrates that Indians desire South African citizenship in the fullest sense of the word, a longing for inclusion that is asserted through an Afrindian identity. Afrindian Fictions: Diaspora, Race, and National Desire in South Africa examines Afrindian identity and blurs the racial binary of black and white interaction in South African studies as well as unsettles the East-West paradigm of migration dominant in South Asian diaspora studies.While offering incisive analyses of the work of the most important South African Indian writers today--Ahmed Essop, Farida Karodia, Achmat Dangor, Imraan Coovadia, and Praba Moodley among others--the author also places South African Indian fiction within broader literary traditions. Rastogi\u27s project of recovery shines a light on the rich but neglected literature by South African Indians. The book closes with interviews conducted with six key South African Indian writers. Here the authors not only reflect on their own writing but also comment on many of the issues raised in the book itself, particularly the role of Indians in South Africa today, and the status of South African Indian writing .Afrindian Fictions is a valuable introduction to South African Indian literature as well as a major interrogation of some of the foundational notions of post-colonial literary studies.https://repository.lsu.edu/facultybooks/1411/thumbnail.jp
Scientometric analysis of synchronous references in the Physics Nobel lectures, 1981-1985 : a pilot study
Get PDFScientometric analysis of synchronous references in the nine Physics Nobel lectures by Nicolaas Bloembergen (1981), Arthur L. Schawlow (1981), Kai M. Siegbahn (1981), Kenneth G. Wilson (1982), Subrahmanyan Chandrasekhar (1983), William A. Fowler (1983), Carlo Rubbia (1984), Simon van der Meer (1984), and Klaus von Klitzing (1985) indicated high variations: No. of Synchronous References ranged from 24 (Meer) to 283 (Siegbahn); Synchronous Self-References ranged from 5 (Rubbia) to 88 (Siegbahn); synchronous references to others ranged from 10 (Chandrasekhar) to 255 (Wilson); Synchronous Self-Reference Rates ranged from 6.66 % (Rubbia) to 65.51 % (Chandrasekhar); Single-Authored References ranged from 15 (Klitzing) to 160 (Wilson); Multi-Authored References ranged from 4 (Chandrasekhar) to 194 (Siegbahn); Collaboration Coefficient in the synchronous references ranged from 0.14 (Chandrasekhar) to 0.75 (Klitzing); and Recency (age of 50 % of the latest references) ranged from 2 (Klitzing) to 18 (Chandrasekhar) years. Seventy five per cent of the references belonged to journal articles. Highly referred journals were Astrophysical Journal, Physical Review B, Physical Review Letters, Arkiv Fuer Fysik, Surface Science, Physics Letters, and IEEE Transactions on Nuclear Science.
See: Scientometrics Vol. 61 No.1, pp.55-68
Immobilization of [VCl3(N-2,6-Me2C6H3)] Complex on Silica Supports:Synthesis and Catalytic Testing for Ethylene Polymerization
No full textThe heterogenization of 2,6-dimethylarylimido-vanadium(V) dichloride via chemical tethering on insoluble silica supports is reported. The effects of the silica particle size, drying conditions, and the reaction time were investigated. The drying conditions of the support were found to be a crucial parameter: drying temperatures over 400 °C were needed to achieve successful catalysis. The supported catalytic systems were characterized by Fourier-transform infrared (FT-IR) spectroscopy, transmission electron microscopy-energy-dispersive X-ray (TEM-EDX), and inductively coupled plasma mass spectroscopy (ICP-MS), while the polymers were characterized by FT-IR, differential scanning calorimetry (DSC), and rheology. Ethylene polymerization tests were performed employing the prepared heterogenized catalysts with methylaluminoxane/diethylaluminum chloride as a cocatalyst. The supported catalyst precursor, when activated with diethylaluminum chloride, promotes the synthesis of polyethylene with seemingly controlled particle size in the absence of reactor fouling, suggesting the successful immobilization of the complex over the inert support. The resulting polymer shows features of ultrahigh-molecular-weight polyethylene (UHMWPE). These findings present a proof-of-concept for a new approach toward the heterogenization of arylimido-vanadium complexes.</p
Shielding and mediating of hydrogen bonding in amide-based (macro)molecules
Get PDFPolymers are long chain molecules comprising continuously repeating building blocks, monomers, which are chemically linked via covalent bonds, for example the C-C bond in polyethylene. A distinction can be made in biopolymers that are made in nature and synthetic polymers that are produced by the chemical industry (plastics). Properties of polymeric materials are not only determined by the primary chemical structure, i.e. the chemical composition of the polymer chain, but also by the secondary interactions between the chains (intermolecular interactions) and the conformation (shape). Especially in biopolymers, a delicate balance between the primary chemical structure, i.e. the chain composition, and intra- and intermolecular interactions is encountered. A well known example is the double helix in DNA, which carries the essence of life. Another example is peptides, or proteins, where unique conformations are dependent on a balance between the sequence of monomer units, here amino acids, and secondary interactions (e.g. hydrogen bonding) between monomers in a single molecule, the formation of the known a- helix and ß-sheet structures, and/or between molecules. Synthetic polymers are in comparison to biopolymers chemically less sophisticated, rendering higher thermal stability. Hence, synthetic polymers can be directly processed via melt routes into end products, for example by means of injection molding or extrusion, while biopolymers such as cellulose (wood) have to be chipped. The conformation and secondary interactions between molecules are essential in synthetic polymers as well. An extreme example in this respect is the simplest polymer on earth: polyethylene (PE). Taking polyethylene as precursor, the industry produces flexible films and containers on one hand, and superstrong fibers with a specific strength and stiffness larger than steel on the other. In these fibers all polymer molecules exist in extended chain conformation perfectly aligned in the fiber direction. Between the apolar PE molecules only relatively weak van der Waals forces reside, but with sufficient length of the molecules the sum of the weak secondary interactions between the molecules induces sufficient frictional forces between the chains that the stress is transferred to the covalent bonds in the main chain upon deformation (in the fiber direction), resulting in high strength and stiffness. These superstrong polyethylene fibers can be considered as 1-dimensional diamond at fast deformation rates, whereas at low deformation rates, i.e. long time-scales, creep occurs. Another disadvantage of these PE fibers is the relatively low melting temperature, approximately 150°C. More ideal would be the use of polyamides (nylons) as precursor for superstrong fibers since polyamides prevent creep by hydrogen bonding and possess high melting temperatures. Chemically polyamides are similar to proteins where the monomers are connected by amide moieties. Polymer chemists often describe proteins as decorated nylons (nylon 2). In the past a lot of industrial research effort has been addressed to the development of superstrong polyamide fibers in a similar way as PE, i.e. drawing and aligning the chains in the fiber direction, unfortunately without success. In processing polyamides, either from the melt or from solution, cooling induces crystallization into chain folded crystals that are comparable with stacks of ß-sheets in proteins. Because of relatively strong interchain hydrogen bonding the chain folded crystals cannot be unfolded like in the case of polyethylene. The aim of the thesis is to shield hydrogen bonding in polyamides temporarily during processing and drawing and to restore the hydrogen bonding once the chains are ideally aligned and extended. Based on the dissolution of polyamides in the superheated state of water (PhD thesis Esther Vinken, TU/e 2008) and inspired by natural silk spinning, where in the glands of spiders and silk worms hydrogen bonded moieties of the proteins are shielded and mediated by water molecules, salts (ions) and pH, a new reversible shielding route in polyamide processing is introduced. Since the amorphous phase in polyamides imposes limitations in investigating the role of water molecules on crystalline hydrogen bonding in polyamides after crystallization from the superheated state of water, low molar mass model compounds, expected to represent the crystalline domains in aliphatic polyamides, have been studied in the dissolution in, and crystallization from the superheated state of water (chapters 2, 3 and 4). The model molecules are bisamide-diols, possessing two central amide motifs (head-tohead) and two hydroxylic end groups. The aliphatic segment length, which separates the polar moieties, can be varied in analogy to polyamides. Hydrogen bonding in polyamides resides in the structural amide planes, which stack to form chain folded crystals. A bisamide-diol with a short aliphatic segment between the amide motifs combined with two longer identical segments between the amide and hydroxyl moieties crystallizes in a stack of crystalline planes in which the molecules are held together by amide-amide hydrogen bonding. In case of a rather equal segment length between all polar groups in the bisamide-diol, amide-hydroxyl hydrogen bonding occurs between the structural amide planes. Hence, the role as a model compound is questionable in such a scenario. Nevertheless, the thermodynamic, structural and conformational behavior is, identical to polyamides, dependent on a balance between thermal motion and hydrogen bonding efficiency. Both bisamide-diols are soluble in the superheated state of water. During crystallization upon cooling the interaction of water molecules with the amide motifs erases the conformational limitations of the intrinsically rigid amide moieties. The extra degree of freedom during crystallization entails ideal crystalline hydrogen bonding, stabilizing the crystalline structures. Moreover, water molecules can be trapped within the crystal lattice during crystallization. In the second part of the dissertation, water molecules are assisted by a series of Hofmeister ions in shielding and mediating of hydrogen bonding in polyamides. The Hofmeister series is a classification based on the hydrating nature of ions, known as kosmotropic and promoting the organization of water molecules, or non-hydrating character of ions, referred to as chaotropic and disordering the water structures. Close to the Brill transition temperature, a reversible crystal transformation that arises due to variations in aliphatic molecular motion and hydrogen bonding efficiencies, polyamides can be dissolved in the superheated state of water. With increasing ionic strength large non-hydrating ions of halogenic origin, such as bromide and iodide, perturb the hydrogen bonding network between water molecules. Since the diffusivity of water molecules and its solutes increases, water molecules and small strongly hydrating cations penetrate the polyamide crystal at lower temperatures, perturbing the amide-amide hydrogen bonding in the crystal. Next to the suppression of the dissolution temperature, the crystallization temperature upon cooling decreases as well. To minimize the nonpolar surface area, hydrophobic hydration entails secretion of the anions to the hydrophobic methylene segments at high ionic strength. With the interaction of the cations, preferably lithium, a charge distribution along the polyamide chains is formed that suppresses crystallization even at room temperature. Extensional deformation of the aqueous polyamide solution in excess of water results in the migration of ions, restitution of intermolecular hydrogen bonding and orientation. However, although the aqueous solutions can be deformed into drawable filaments, the strength upon crystallization is lost due to the absence of chain overlap, meaning that stress transfer between the chains is insufficient. To promote chain overlap a processing (extrusion) route for concentrated polyamide LiI solutions is explored in chapter 6. Here, the hydrogen bonding is temporarily shielded by ions to prevent the formation of chain folded crystals during processing. Strain induced crystallization upon drawing restores amide-amide hydrogen bonding, high orientation factors and lattice perfection. Though these aspects are essential in realizing high strength and high modulus materials, the crystallinity and the melting temperature are considerably suppressed by incomplete removal of ions. Time-resolved wide angle X-ray experiments reveal that the migration of ions is primarily time-dependent at temperatures above the glass transition temperature. Efficient migration of ions in superheated water at 150°C results in high crystallinities and consequential high melting temperatures, preserving the high orientation and crystal perfection. However, experimental verification of the ultimate goal: the development of high strength and stiff polyamide fibers, could not be realized due to the intrinsic problem of removing all ions effectively that requires optimization in terms of fiber diameter and spin/drawing parameters. Ideal experimental conditions are of technological origin and require optimization in an industrial environment. The author hopes that the results in this dissertation will contribute to a new technology resulting to a new generation of (super)strong polyamide fibers
Controlling the melting kinetics of polymers : a route to a new melt state
Get PDFPolymers play an important role, both in nature and in the modern society. In contrast to polymers in nature, the so-called biopolymers, man-made polymers are thermally more robust and are in majority processed via the melt (plastics). In the case of thermoplastic polymers (> 70% of all synthetic polymers), the viscosity of the polymer melt poses a limit on the processability, notably for polymers possessing a high(er) molar mass M. Based on experimental evidence, the (zero-shear) viscosity of polymer melts, ??0 , scales with Mw 3.4 (Mw is the weight-average molar mass). This implies that the melt-viscosity increases with more than a factor of 10 upon doubling the molar mass! Since the properties of polymers in the solid-state also increase with increasing molar mass, notably the strength and toughness, the processing of thermoplastic polymers, e.g. injection-moulding, extrusion, fiber spinning, is often a compromise between the ease of processing, viz. preference for lower molar mass (easy flow), and properties, with preference for high(er) molar masses. The current knowledge of polymer melts is rather well developed and based on a simple but elegant model put forward by P.G. de Gennes (Nobel prize for Physics), the so-called reptation model. In this model, the motion of a polymer chain in the molten state is hindered by its neighbors (entanglement), which generate a virtual "tube" confining the chain on a one dimensional pathway. The constraint chain dynamics gives rise to a characteristic time for a chain to diffuse its own length in the tube. Scaling as M3. The same scaling is predicted for the zero-shear viscosity. The experimentally observed discrepancy, see above ??0~ M 3.4, from the 3.0 dependence is attributed to "contour-length fluctuations" i.e. fluctuation-driven stretching and contractions of the chain along the tube. In Chapter 2, it is shown that the zero-shear melt-viscosity of carefully prepared samples of high molar mass polyethylene (PE), possessing a narrow molecular weight distribution, indeed follow the predictions of the reptation model, viz. ??0 scales with M3 .The advantage of high molar mass polyethylenes is that chain-end effects do not play an important role or can be ignored. As a consequence of these results, high molecular weight polyethylenes have been used as a model substance throughout the thesis, notably ultra-high-molecular-weight PE (UHMW-PE). In the solid state, entanglements can be removed effectively by dissolution of the polymer. In dilute solutions, below the so-called overlap concentration ??*, entanglements can be removed completely. In the case of crystallizable polymers, such as PE, the reduced entanglement density can be made permanent since the long chain molecules form folded-chain crystals, a well-studied phenomenon in polymer physics. A more elegant and also technologically more advanced way to generate disentangled PE crystals is via direct polymerization in the reactor. At low polymerization temperatures and low catalyst activity/concentration, individual growing chains will form their own folded chain crystals. In the limiting case where the growing chains are separated far enough from each other, monomolecular crystals can be formed. If completely disentangled PE structures can be obtained via solution-crystallization and/or via direct controlled synthesis, the intriguing question is whether this disentangled state will be preserved upon melting and what is the time scale to generate a fully entangled equilibrium polymer melt. This question is the key issue of the thesis. What happens when we start from a non-equilibrium disentangled state and cross the melting temperature into the molten state? How does the equilibrium entangled melt state get restored? In Chapter 2 it is shown that starting from the disentangled state, in this case nascent UHMW-PE powder, that it takes time to "build-up" the plateau modulus in the melt, indicative of an entanglement formation process. The entanglements formation scales as the reptation process (Mw 3). Parallel to rheology measurements, solid-sate NMR is used to monitor the change in chain mobility. The time scale to reach the equilibrium melt as probed by the NMR and Rheology experiments is very different, suggesting that restrictions in local chain mobility monitored by NMR are realized at an earlier stage than restrictions in segmental mobility inferred from rheological experiments. A peculiar phenomenon of nascent reactor powders is their high melting point, close to or equal to the so-called equilibrium melting point of PE. This phenomenon has puzzled researchers in the field for many years and various explanations have been given such as the growth of extended-chain crystals instead of folded-chain crystals or extensive reorganization during the melting process, but all these explanations were not supported by experimental data which show that nascent UHMW-PE reactor powders consist of "normal" folded-chain crystals without extensive reorganization (thickening) during the melting process. In Chapter 3 it is shown that the unusual high melting temperature of nascent UHMW-PE is related to the tight-folding (adjacent re-entry mode) in the crystals. Melting is a cooperative process over several chain stems of the same crystal in contrast with e.g. melt-crystallized samples where a chain is incorporated in various folded-chain crystals and topologically, prior to the melt, is in contact to different chains. The melting mechanism as discussed in chapter 3, can be utilized by controlling the melting process of UHMW-PE nascent reactor powders. When decreasing the heating rate, the melting process starts by detachment of single stems from the (lateral) surface of the crystals. In this process, the molten chain ends can entangle with chain ends from other partly molten crystals, whereas the core of the molecule is still in the crystal, viz. in the tight folded-chain conformation. As discussed in Chapter 4, after complete melting by this mechanism, a heterogeneous melt-state is obtained since the central part of the individual chains is prevented from taking part in the entangling process. By NMR experiments, it is observed that on decreasing the heating rate, the time required to restrict the chain conformations at the local scale increases. In rheometry it is observed that with the increasing time to restrict the chain conformations, the time needed for the modulus to buildup increases. Ultimately, it is feasible to melt the sample so slowly that the restriction in the chain conformation in part of the sample can be inhibited, maintaining the partially high local mobility. Since restrictions in the chain conformations can not be achieved, the cooperative motion needed for the translational mobility is absent. As a consequence normal chain reptation is slowed down considerably and a long-living partially disentangled melt is obtained. This new melt state shows a decreased plateau modulus and viscosity, whereas the terminal stress relaxation rates remain the same. The observations are that stress relaxation is achieved without "normal" reptation of chains in the tube. This is explained by the partial reptation of the chains since only a fraction of the whole chain is required for the stress relaxation. The consequences of a heterogeneous melt-state are discussed in Chapter 5. The observations are that the disentangled chainsegments crystallize faster than the entangled chains. This suggests that intra-molecular homogeneous nucleation occurs faster than the heterogeneous nucleation. Moreover, after crystallization from the heterogeneous melt, the solid-sate drawability is still remarkably high, indicative of a certain state of disentanglement. Thus can be drawn into a fiber in the solid state because large disentangled blocks are present in the crystal. The melting behavior of solution-crystallized UHMW-PE is studied in Chapter 6. Similar to the nascent disentangled crystals, these folded-chain crystals can be melted by consecutive detachment of chain stems from the crystal substrate. The differences in melting behavior, revealed during different heating rates, have consequences on the chain dynamics. Unlike the nascent disentangled samples, where modulus builds up with time, the solution-crystallized sample entangles immediately upon fast heating. The remarkable difference in the rate of entanglements formation can be attributed to the differences in the stacking of crystals, prior to melt. The solution-crystallized samples double their crystal size via intermixing of the regularly stacked crystals which upon melting facilitate the entanglement formation process.contrary to the nascent disentangled samples where no regular stacking occurs. An alternative route to achieve a reduction in the melt viscosity is explored in Chapter 7, by the addition of the single-walled carbon nanotubes (SWNTs). When varying the content of SWNTs, the dynamic viscosity/storage modulus shows a minimum. The decrease in viscosity is attributed to the selective adsorption of the high molar mass fraction onto the nanotube surface. The increase in viscosity upon further increasing the nanotube content is attributed to the formation of an elastic nanotube-polymer network. The concepts presented in the thesis, based on experimental validation, could have an important impact on novel processing techniques for UHMWPE, e.g. sintering of UHMW-PE into products for demanding applications such as artificial hip-and knee joints and, solventfree processing routes for UHMW-PE fibers and tapes
Aliphatic hydrogen bonded oligomers and polymers from natural resources
Get PDFChemistry is by definition the science of matter, the science of the transformation of the substances and for this reason and also for practical issues derived from its technological applications, has interested the different populations since ancient times. The strong connection of this branch of science with the industrial world has promoted its interest in the development of new materials that could substitute or improve traditional and natural materials. Although this development has not always been a direct consequence of a well specified research or demand, (in fact many important discoveries are result of serendipity) periods can be distinguished during the history of the chemistry in which the different industrial processes or researches were born considering demands and requests of the moment. For example the Alkali industry, probably the first important chemical industrial process, can be considered as born to serve the textile industry, leading sector of the second industrial revolutions. This continuous adaptation also led to development of materials such as plastics and synthetic polymers directly correlated to petroleum industry. Synthetic polymers, initially introduced in order to substitute more expensive materials like natural fibers or traditional materials like wood, glass, and ceramics, were improved with different and better properties with respect to the natural materials. In particular, exploitation of chemistry to meet challenges in material science, a detailed understanding of structure-property relationship is essential to meet the ultimate properties. These materials are characterized by their simple chemical structure and therefore good thermal stability that makes them processable in the molten state and outperform the thermal degradation of many natural materials is essential. Nowadays the scarcity of oil resources and the environmental and political issues are encouraging the production of environmental friendly materials. A new request is once again influencing the chemistry world and new answers from polymer science are expected. Many different projects on bio-polymers have been carried out in the last decades in several different laboratories. A lot of interest is paid by petrochemical industry to bio-based materials with the intent of replacing exiting plastics. The industrial interest is from one side promoted by the possibility of achieving green image and from the other side is due to the possibility of minimizing the exploitation of oil resources. However, many bio-based plastics represent durable materials that cannot prevent one of the most important issues, the biocompostability. In this thesis we have explored the possibility of using alternative feedstock in order to produce plastics. We have focused our attention on bio based monomers and the application of such monomers as a powerful method of tailoring thermal and mechanical properties of interesting known materials. In particular the role of secondary interactions such as hydrogen bonds on the crystallization of new bio-based polyamides and the role of bio-based monomers in influencing the secondary interactions has been investigated. Among many materials that can be considered as a source of bio- based polymers or monomers we have also explored a new approach using water under specific pressure-temperature conditions to hydrolyze keratins that is a part of Chapter 2 in this thesis. Our observations are that under controlled hydrolysis conditions it is feasible to extract oligopeptides with well defined sequences of amino acids (LC-MS and HPLC) and re-synthesize them via Solid State Peptide Synthesis by attaching aliphatic and hydrogen bonding motifs to the synthesized oligopeptides in order to promote self assembling phenomena. New semi-crystalline polyamides and co-polyamides from bio-based sebacic acid (SA), 2,5-diamino-2,5-dideoxy-1,4;3,6-dianhydroiditol (diaminoisoidide, DAII) as well as from 1,4-diaminobutane (DAB), have been synthesized. These monomers can be derived from castor oil (SA), starch (DAII) and putrescine (DAB). Synthetic routes, involving interfacial polycondensation, solvent-free bulk polycondensation accomplished by Solid State Polymerization (SSP) after a prepolymerization in the melt are reported in Chapter 3 where the chemical structure of the synthesized bio based polyamides and copolyamides was proven using 2D NMR and FT-IR spectroscopy. Moreover the influence of DAII/DAB content on the crystal structure and melting points of the polyamides were investigated using wide-angle X-ray diffraction and DSC techniques. In chapter 4, FT-IR, CP/MAS NMR and WAXD are successfully employed for the analysis of the structural behavior and mobility of the polyamides and copolyamides with a different DAII/DAB content as function of temperature. The contribution of DAII causes a conformational disorder of the polyamides and thus influences the crystal structure and the properties of these materials. Transmission electron micrographs of crystals of bio-based polyamides and the respective electron diffraction patterns, coupled with XRD data and modeling experiments confirm the influence of DAII content on the crystal structure of these materials and also on the mechanical properties. The latter is confirmed by DMTA (chapter 5). Last chapter in the thesis highlights possible technological aspects in these bio-polymers
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