Characterization Of A Glycerol Based Polymer Environmental Sciences Essay

Published: 2021-09-30 17:55:04
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In oleochemical industry, glycerin ( 1,2,3-propanetriol ) is ever produced as a byproduct in the fabrication of acids, soaps, methyl esters, intoxicants or nitrogen-containing derived functions. It can besides be made from propene via epichlorohydrin ( 1-chloro-2,3-epoxypropane ) . However, the petrochemical supply path is less of import due to the increasing supply of glycerin from oleochemical industry, the high monetary value of propylene and the demand for epichlorohydrin for other intents ( Gunstone & A ; Henning, 2004 ) .
Figure 1.1 Glycerol
Glycerol possesses a alone combination of physical and chemical belongingss which are utilized in many commercial merchandises. It is hygroscopic, colourless, odorless, syrupy, sweet-tasting, low boiling point, non-toxic, demulcent, a good dissolver, and H2O soluble. Besides, it is easy biodegradable ( Gunstone & A ; Henning, 2004 ) . Furthermore, it is really stable under normal storage conditions, compatible with many other chemical stuffs, non-irritating in its assorted utilizations, and does non hold negative effects on the environment ( Pagliaro & A ; Rossi, 2008 ) .

The glycerin market is presently undergoing extremist alterations, driven by really big supplies of glycerin originating from biodiesel production. The attempt to cut down the dependance on foreign oil has increased the production of biodiesel and glycerin is the major co-product from the transesterification procedure used to bring forth biodiesel. Hence, there is a demand to happen new utilizations for glycerin. Polymerization is one of the methods which big sum of glycerin can be used ( Wyatt et al. , 2006 ) .
There two types of polymerisations. First, soluble merchandises are obtained irrespective of the extent to which the reaction is carried toward completion. The merchandises formed are chiefly additive polymers. The 2nd type of polymerisation is those that lead to gelled or indissoluble merchandises, provided that the reaction is carried far plenty. The reactants are capable of bring forthing big three dimensional molecules ( Flory, 1941 ) .
Harmonizing to Flory ( 1941 ) , gelation occurs merely when there is the possibility of limitless growing in three dimensions. It is a important feature of polymerising systems to hold a aggressively defined gel point at a certain critical extent of reaction which is independent of temperature, sum of accelerator and so on.
Through polymerisation of glycerin, the pre-polymers synthesized could be farther reacted to bring forth longer ironss of hyperbranched polymers. Hyperbranched polymers belong to the household of supermolecules known as dendrimers. Dendrimers are extremely branched monodispersed molecules produced by multistep syntheses. Preparation of dendrimers requires a high grade of pureness of the get downing stuff and high outputs of the single man-made measure. On the other manus, hyperbranched polymers are indiscriminately branched molecules prepared by a simple one-step reaction ( Wyatt et al. , 2006 ) via polyaddition, polycondensation, extremist polymerization, and so forth, of an ABn monomer ( Vogtle et al. , 2009 ) . Due to their alone combination of low viscousness, first-class solubility, and facile synthesis, hyperbranched polymers have received important attending ( Lin, Q & A ; Long, T.E. , 2003 ) .
Chemical reaction of the functional A groups with the functional B ( matching ) groups of a 2nd monomer molecule gives rise to randomly branched molecule. Since the C groups are present in surplus ( n a‰? 2 ) , crosslinking are avoided from the beginning. Chemical reaction can be brought to a standstill by addtion of stopper constituents. Since the synthesis of hyperbranched polymers does non affect matching to core molecule, but merely ABn monomers react with one another. Both bifurcate molecules and additive sequences possibly formed ( Vogtle et al. , 2009 ) .
Hyperbranched polymers produced from diacids ( A2 ) and glycerin ( B3 ) are an illustration of the AB2 system. AB2 monomers are non readily available and kinetic computations show that the first condensation reaction, which produces an AB2 species, is faster than the subsequent polymer extension. Therefore, the balance of the reaction progresses as polycondensation between AB2-type species prior to the gel point. Several methods have been used to avoid gelation in A2+B3 systems, including executing the reactions in dilute solutions or responding them in the absence of dissolvers while monitoring.
This glycerol-based polymer is expected to demo similar belongingss and features as polyalkylene ethanediol ( PAG ) . A polyalkylene ethanediol holding the general expression: HO- [ R-O- ] n H in which N has a value of at least 2 and R is an alkylene extremist containing at least 10 C atoms. PAG liquid are used as man-made lubricators in many diverse applications. Therefore, glycerol-based polymers could besides hold the possible to be use every bit high public presentation lubricator, coolant or as a lubricant additive ( such as viscousness qualifier ) .
Materials with polymeric constructions can be used in lubricator to heighten its belongingss, such as viscousness, pour point and so on. It can be used as get downing stuff for certain types of additives. These polymeric additives can be viscosity modifier, pour point sedatives, emulsifiers and demulsifiers, and foam inhibitor in lubricators ( Totten, G.E. et al. , 2003 ) .
Oils can be effectual lubricators at low temperature. However, at higher temperature, they become less effectual. To get the better of this job, viscousness qualifiers are utile in minimising viscousness fluctuations with temperature. Viscosity qualifier is a polymer with mean molecular weights of 10000 to 150000. At all temperatures, viscousness qualifier is able to increase oil 's viscousness. The thickener of oil at lower temperature is less than that at higher temperature. At low temperatures, the polymer molecules busying a little volume have a minimal association with the majority oil. The state of affairs is reversed at high temperatures as the polymer ironss expand due to the increased thermic energy. Besides, at higher temperatures, polymers are more soluble and hence do the viscousness to increase ( Totten, G.E. et al. , 2003 ) .
There are two types of viscousness qualifiers available commercially: olefin-based polymers and ester polymers. Polyisobutylenes ( PIBs ) , olefin copolymers ( OCPs ) , and hydrogenated styrene-diene ( STDs ) polymers. Ester polymers include polymethacrylates ( PMAs ) and styrene ester polymers ( SEs ) ( Totten, G.E. et al. , 2003 ) .
Literature Review
In a research done by Wyatt and his colleagues ( 2006 ) , fresh oligomeric prepolymers were synthesized by acid-catalyzed condensation of glycerin with iminodiacetic. The prepolymers were obtained after purification by chromatography in an mean output of 62 % . The compounds were characterized by utilizing 13C NMR, 1H NMR, matrix assisted laser desorption ionization-time of flight-mass spectroscopy, and gel pervasion chromatography. It was discovered that additive merchandises bearing cyclic urethane constructions were obtained in the reaction between iminodiacetic acid and glycerin.
Qi Lin and Timothy E. Long ( 2003 ) studied the polymerisation of A2 with B3 monomers to bring forth hyperbranched poly ( aryl estrer ) s. A dilute bisphenol A ( A2 ) solution was added easy to a dilute 1,3,5-benzene tricarbonyl trichloride ( B3 ) solution at 25A°C to fix hyperbranched poly ( aryl ester ) s in the absence of gelation. The molar ratio of A2: B3 was maintained at 1:1. The maximal concluding monomer concentration was ~0.08 M. The phenol functionalities were quantitatively consumed during the polycondensation. This was showed in 1H NMR spectrometry and derivitization of terminal groups. Two theoretical account compounds were synthesized to place 1H NMR resonances for additive, dentritic, and terminal units. The concluding grade of ramification was determined to be ~50 % . The hyperbranched polymers exhibited lower glass passage temperatures compared to their parallels.
J.F. Stumbe and Bernd Bruchmann ( 2003 ) besides used the A2+B3 attack to fix hyperbranched polyesters with controlled molecular weights and belongingss. The procedure was carried out by responding glycerin and adipic acid without any dissolvers. Tin accelerators was used. The merchandises were evaluated by size exclusion chromatography ( SEC ) analysis and NMR spectrometry to find molecular weights and grades of ramification.
A survey was besides carried out on the glycerin esters from reaction of glycerin with dicarboxylic esters. The glycerin esters were synthesized by the base catalyzed reaction of glycerin with aliphatic dicarboxylic acid esters ( such as dimethyl oxalate, dimethyl glutarate, dimethyl adipate, etc ) . Assorted parametric quantities that may impact the transesterification were studied in order to optimise the output of merchandises. The reactions were carried out by changing the glycerol/ester molar ratios. The optimal ratio was 4:1, whereby the measure of the monoester was 60 % after 8 h. The transition decreased somewhat when the grinder ratio exceeded 4:1. At higher temperatures, the sum of monoester in the reaction mixtures increased and it reached a maximal degree after 6 H when the reaction was carried out at 100 A°C to 120 A°C. It took 8 H at a lower temperature. However, the overall output at the terminal of the reaction was non affected by the temperature. The formation of both monoester and diester were produced in an overall output of 80 % after 15 H of reaction clip ( Cho et al. , 2006 ) .
Sunder et. Al. ( 1999 ) carried out a controlled synthesis of hyperbranched polyglycerols by pealing opening multibranching polymerisation. Hyperbranched aliphatic polyethers with controlled molecular weights and narrow molecular weight distribution were prepared via anionic polymerisation of glycidol with rapid cation-exchange equilibrium. Glycidol which represents a cyclic AB2 monomer was polymerized in a ring-opening multibranching ( ROMBP ) . The anionic polymerisation was carried out under slow add-on conditions with partly deprotonated ( 10 % ) 1,1,1-tris ( hydroxymethyl ) propane ( TMP ) as the instigator. 13C NMR, MALDI-TOF spectroscopy, vapor force per unit area osmometry ( VPO ) , and GPC were used to qualify molecular weights and polydispersities of the polyols formed. The 13C NMR spectra used to measure the grade of ramification ( DB ) ranged from 0.53-0.59. A complete fond regard of hyperbranched polymers to TMP instigator and the absence of macrocyclics were showed in MALDI-TOF spectra. There was no macrocyclics or hyperbranched supermolecule obtained, due to decelerate addtion.
T.J. Mulkern and N.C. Beck Tan ( 2000 ) studied a series of blends of hyperbranched polyester with high molecular weight polystyrenes. The processability and compatibility in the blends were investigated as a map of volume fraction of hyperbranched polyols ( HBP ) added and responsiveness of the matrix stage. Due to its low viscousness and high responsiveness, HBP polymers are suited for reactive polymer blending. Through processing and rheological surveies, it was found that HBPs are effectual processing AIDSs. A important bead in the blend viscousness occurs instantly on add-on of HBP, even at degrees every bit low as 2 vol. % .
In 1934, Herman Bruson discovered a man-made oil additive when he was researching the synthesis and possible applications of longer alkyl side concatenation methacrylates. Bruson 's innovation, polymethacrylates ( PMAs ) was found to hold the possible to work as thickening or viscousness index humanitarian for mineral oils. It increases viscousness at higher temperature more than at lower temperatures ( Kinker, B.G. , 2009 ) . The alkly group in the ester part of the polymer can be altered to obtain merchandises with better oil solubility and viscosity-improving belongingss. It besides have good compatibility with a big figure of refined and man-made basestocks.
In a survey by Duncan and Turner ( 1997 ) , blends of lubricant basestocks with high viscousness complex intoxicant esters were produced. The blend comprises of a polyhydroxyl compound R ( OH ) N, a polybasic acid and a monohydric intoxicant. The complex intoxicant ester showed a pour point of less than or equal to -20A°C and a viscousness in the scope about 100-700 Central Time at 40A°C. The lubricating oil harmonizing to Duncan and Turner 's innovation has first-class prurience as determined by engine public presentation, vane pump trial, Yamaha Tightening Test, and reduced valve lodging. Besides, it has good stableness as evidenced by the consequences of RBOT and Cincinnati Milacron trials. The lubricator has besides unexpected biodegradability as measured by Sturm trial ( Duncan et al. , 1997 ) .
Hunt et Al. ( 1993 ) carried out supercritical fluid extraction to analyze liquid poly ( alklene ethanediol ) ( PAG ) lubricators and sorbitan ester preparations. The PAG matrix was adsorbed onto silicon oxide and the selectivity obtained by this method was compared with that obtained by the direct extraction of adsorbed and unadsorbed PAG. Extraction was besides done for unadsorbed PAG through the in-line column and it was successful in dividing additives from all but the lowest molecular mass PAG oligomers. This extraction process enabled fractional process of the merchandise and could be used as a sample readying technique for farther spectroscopic analysis.
It is hard to bring forth polymers with narrow molecular weight distributions by traditional methods. Supercritical fluid engineering is applied to get the better of the conventional methods. The solubilty parametric quantity of supercritical fluid can be tailored. Selective extraction and fractional process are possible from multi-component mixtures. The key to doing high quality polymers is to guarantee precise control of molecular weight and polydispersity at high output while maintaining residuary contaminations below acceptable tolerance degrees.
Hernandez et. Al. ( 2005 ) tested the turn overing weariness of three polyglycols ( PAG-9, PAG-12 and BREOX-B-135X ) . Polyglycols ( besides called PAG or polyalkylene ethanediols ) are widely used in the lubrication industry. These compounds have really high viscousness indexes, really low pour points, a high thermic conduction with regard to mineral oils, hydrolytic stableness, etc. Rolling fatigue trials were carried out utilizing IP-300 criterion in order to obtain the word picture of the fluids. A four ball trial machine was used and 10 % life ( L10 ) and 50 % life ( L50 ) were obtained. The stress-time curves for L10 and L50 were besides determined. All polyglycols were tested under boundary lubrication government ( I» & lt ; 1 ) where in turn overing contacts the surface manner of failures prevails.
In oils of the same household, the pressure-viscosity coefficient is comparatively changeless. An addition in viscousness improved the minimal movie thickness with the attendant addition of the I» ratio. Fatigue life is mostly a map of the ratio of lubricating movie thickness to composite surface raggedness ( I» ratio ) . Differences in I» ratio for the three polyglycols resulted in different grimness interactions and turn overing contact weariness lives. With respect to turn overing contact weariness, the pick of viscousness category should avoid grimness interaction, so that the lone manner of failure will be subsurface failure. Although mean force per unit area in the contact was the same, increase in viscousness from PAG-9 to BREOX-B135X improved the I» ratio from 0.18 to 0.34. At less I» & lt ; 1, operation is in the boundary lubrication government where turn overing contact fatigue life is short, but an addition of I» ratio cut down the grimness interactions and hence rolled contact weariness improved.
An probe was so carried put by Garcia and colleagues on PC-SAFT volumetric and stage behaviour of C dioxide + PAG or POE lubricant systems. The densenesss of man-made PAG oil was measured from 283.15 K to 333.15 K while the solubilities of CO2 in this oil was measured from 253 K to 333.15 K. Molecular weight of the lubricator was estimated utilizing fast atom barrage ( FAB ) . Molecular weight and experimental densenesss were used to cipher characteristic parametric quantities of PC-SAFT theoretical account for several commercial PAG oils. Movable characteristic parametric quantities were used for POEs.
The thermophysical belongingss and phase behavior of CO2-lubricant oil mixtures is of import for the design of infrigidation and air-conditioning. The go arounding fluid comes into contact with the lubricator used in compressors and a part of the oil is transported into the infrigidation circuit with assorted effects in footings of public presentation. If the oil is non-miscible with the refrigerant, the compressor may be damaged due to hapless oil return to the compressor. Oil may roll up inside the heat money changer tubings cut downing heat transportation capablenesss, enthalpy alteration and ensuing in an overall decrease of the infrigidation capacity and rhythm public presentation. In add-on, high solubility of the refrigerant in the lubricator may cut down the viscousness of the oil-rich stage and consequences in lower lubrication belongingss which gives rise to dislocation of the compressor mechanical parts.
Hauk & A ; Weidner ( 2000 ) studied the thermodynamic and fluid-dynamic belongingss of C dioxide with different lubricators in chilling circuits for car application. The information of the binary mixture were measured at temperatures between 5 and 100 A°C under force per unit area of up to 150 saloon. The stage behaviour was observed qualitatively in a hugh-pressure position cell and was determined in an sterilizer based on a static-analytical method. The viscousness of the lubricator saturated with C dioxide was measured with an integrated vitreous silica viscometer.
The pertinence of lubricators in car-climatization systems can be evaluated with the cognition of stage behaviour and the resulting viscousness of gas-saturated lubricantsThe stage behaviour of oils with C dioxide can be divided into three different types which are binary systems with closed miscibility spreads, systems with unfastened miscibility spreads, and systems that show barotropic phenomena. Oils that show barotropic behaviour in contact with tight C dioxide are non recommended as lubricators. Oils with complete or limited miscibility with C dioxide may be used.
Firdovsi & A ; Yagoub ( 2006 ) investigated the man-made heat bearer oil composings based on polyalklene ethanediols. Thermal stableness, mass loss on vaporization at 250 A°C, 350 A°C and altering the specifications after heating at 300 A°C for 10 Hs were besides studied. The prepared PAGs have been taken as basic constituents for heat bearer oil composings. It was discovered that the specifications of PAGs such as viscousness indices, pour points, acerb figure and brassy points changed dramatically upon heat handling. In order to better the thermic stableness and viscousness indices, anti-oxidant and anti-foaming additives were added to the base stuff to make optimal composings. The obtained heat bearer oils showed comparable improved belongingss in comparing with commercially available heat bearers.
This undertaking will be divided into 2 phases as listed below. Poly ( glycerol-diacid ) polymer will be prepared by utilizing different hydrocarbon concatenation length of diacids ( such as azelaic, succinic and adipic acid ) . The merchandises will be analysed in order to analyze their chemical and physical belongingss.
Phase 1:
Chemical reactions of glycerin with different hydrocarbon concatenation length of diacid compounds ( e.g. azelaic, succinic or adipic acid ) at different mole ratios, are carried out under N2. The mixtures were charged to a reaction vas equipped with distillment setup. The reaction merchandise is allowed to respond at the coveted temperature and clip. Acid value ( AV ) , hydroxyl value ( OHV ) and glycerin content will be measured to keep the reaction advancement. Optimization of the reaction parametric quantities will be studied by changing different reaction parametric quantities such as type and sum of diacid, reaction clip, temperature and force per unit area. The concluding merchandise will be washed, dried and characterised.
Phase 2:
The merchandises obtained will be analysed by utilizing both High Performance Liquid Chromatography ( HPLC ) and Gas Chromatography-Mass Spectrometry ( GC-MS ) . Other instrumentality such as Fourier Transform Infrared Spectroscopy ( FT-IR ) , Nuclear Magnetic Resonance ( NMR ) and Gel Permeation Chromatography ( GPC ) will besides be utilised to further corroborate their molecular construction. Physical belongingss of the merchandises obtained such as viscousness, solubility, brassy point, fire point, denseness, specific gravitation, biodegradability, and oxidative stableness will be performed.
Expected consequence:
Polymers ensuing from the copolymerisation of glycerin with diacids of changing C concatenation length, molecular construction, and composing will be obtained. Structures holding more than two free acid functionalities at the end-terminals can happen merely after ramifying. As the clip of reaction returns, the viscousness increases which limits the interaction between the reactants and the turning polymers. The H2O solubilty of the oligomers decreases with increasing concatenation length of the diacid monomers of the diacid monomers used in fixing the oligomers. This glycerin based polymers are expected to possess broad scope of applications such as cosmetics and lubricators.

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