Diary:Polymer Journal ( 2014 ) 46, 2–13
- This paper is about the lipase catalysed synthesis of reactive polyester. In this synthesis lipase used as natural accelerator. The synthesis of reactive polyester was done by pealing opening add-on condensation polymerisation ( ROACP ) reaction with desiccation. Cyclic anhydride and diol were used. Itaconic anhydride ( IAn ) is renewable biomass stuff so it was ideal monomer for synthesis of reactive polyester. IAn is five membered cyclic anhydride. ROACP did non possible between IAn and diol so the monomer succinic anhydride ( SAn ) or glutaric anhydride ( GAn ) were used with IAn and glycol. The glycol used were 1, 4-butanediol ( BD ), 1, 6-hexanediol ( HD ), 1, 8-octanediol ( OD ) and 1, 10-decanediol ( DD ). ROACP reaction of IAn with the glycols in the ratios of IAn: glycol with lipase as a accelerator in presence of molecular screens were studied at 25C in methylbenzene for 120h. From the GPC analysis it is observed that all the reaction remained inhomogenous during the reaction and gave merely low-molecular weight merchandise with MNbetween 150 and 390. The NMR consequence show that get downing IAn wholly consumed in pealing opening reaction so IAn entirely does non demo RCACP so the add-on of other constituent or altering reaction status necessary. For these regioselectivity and substrate selectivity scrutiny of IAn done by utilizing exemplary reaction of IAn and n-octyl intoxicant. For regioselectivity observation ROA reaction was performed with Novoenzyme 435 accelerator without molecular screen in methylbenzene at 25?C with stirring. The ?-selectivity value without lipase was 90 % and with lipase contact action was 49 %. It was because the ?-carbonyl group is sterically more favorable than ?-carbonyl group group adjacent to the vinylidene group so it confirmed that reaction catalysed by lipase. In ROACP reaction foremost pealing opening add-on ( ROA ) reaction between cyclic anhydride and glycol and after that desiccation condensation reaction between intoxicant group and carboxylic acid group occur. Out of four glycol OD gives good consequence in footings of output, molecular weight and figure of unit per molecule. ROACP utilizing IAn, SAn or GAn and glycol produced polyester in good output. From the SAn polyester with MNvalue of 650-3510 with 1.3-2.6 units per molecule were obtained and from GAn these value were 560-3690 and 1.2-3.1 severally. The polymer synthesized have application as macromonomer, telechelic or crosslinking reagent.
2. LITERATURE SURVEY
The reappraisal of this manuscript and presentation of positions has been conducted based on an extended study of the manuscripts depicting similar or related research.
- Renewable biobased polymeric stuffs: facile synthesis of itaconic anhydride-based copolymers with poly ( L-lactic acid ) transplant ( Okuda et.al, 2012 )
Biobased stuff are environmental friendly so these stuff now a yearss used largely for synthesis organic compound. Current paper used itaconic anhydride ( IAn ) and lactic acid ( LA ) as a renewable get downing stuff for synthesis of biobased polymeric stuff of poly ( lactic acid ) ( PLA ) -graft copolymer. Synthesis of Poly ( lactic acid ) ( PLA ) was done by two manner ; ring-opening polymerisation of lactide with a assortment of metal or nonmetal accelerators and direct polycondensation of lactic acid ( LA ) with acerb accelerators. Poly ( lactic acid ) ( PLA ) -graft copolymer were synthesized by two manner macromonomer attack and copolymer attack.
First the utilizing IAn the methacryloyl-type polymerizable PLA macromonomer ( IAn-PLA Macro ) were formed and so its copolymerization with n-butyl methacrylate ( BMA ), n-butyl propenoate ( BA ), methyl methacrylate ( MMA ) or ethyl methacrylate ( EMA ) to give transplant copolymer with molecular weight Mn up to 1.61?105and biomass content more than 34wt %. When copolymer approached using IAn as comonomer for extremist polymerisation with BMA used so IAn-BMA copolymer with Mn 5.76 104 obtained. These two attacks are used for synthesis of PLA-graft copolymer as “biomass plastic” holding assorted application.
2 ).Enzymatic Polymerization: A New Method of Polymer Synthesis ( kobayashi 1999 )
Enzymatic polymerisation refers to polymerization utilizing an stray enzyme outside the biological system through non-biosynthetic tracts. The present article gives thought about development of enzymatic polymerisation technique. Hydrolases and oxidoreductase types of enzyme were used for polymerisation. By utilizing these enzymatic polymerisation method assorted stuff synthesized including polyose like chitin, cellulose, xylan and amylose and un-natural polyose by glycosidase through assorted monomer. Oxidoreductase initiated vinyl polymerisation. The polymerizability was depend on pealing size, opposing to chemical contact action where pealing strain is operative. Enzymatic polymerisation has advantages of high selectivity, ability to run under mild status, accelerator recyclability, and biocompatibility.
3. Dehydration polycondensation in H2O for synthesis of polyesters by lipase accelerator. ( Suda et al., 1999 )
Lipase is natural accelerator used for synthesis of polyester.In the present paper aliphatic polyester was synthesized by desiccation polycondensation in H2O by utilizing lipase as accelerator. Polymerization was carried out at 45°C for 24 H.size exclusion chromatography ( SEC ) was used for molecular weight finding. Methanol was used for isolation by reprecipitation. Effect of reaction parametric quantity and the lipase beginning on the molecular weight and the polymer output have been consistently measured in the combination of sebacic acid and 1,8-octanediol. When the experiment was carried without the lipase ( command experiment ) so the polymerisation did non happen bespeaking that polymerisation takes topographic point due to lipase as accelerator. The consequence of temperature, dissolver and sum of enzyme and monomer were consistently measured. When enzyme concentration increased it was observed that the output was increased. It was seen that monomer sum besides affected polymerisation behavior.The polymerisation behavior depended on concatenation length of the monomer in the polymerisation of a co-dicaboxylic acid and ethanediol. NMR and MALDI-TOF mass spectroscopy was used for terminal construction analysis.
4.Enzymatic polymerisation towards biodegradable polyester nanoparticles ( Taden et al., 2003 )
Biodegradable polymer nanoparticles synthesized from the direct enzymatic polymerisation of miniemulsion consisting of lactone nanodroplets. For polymerisation of lactone lipase as accelerator was really efficient. Lipases were ampiphilic molecule and they adsorb onto the hydro-phobic lactone nanodroplets. Ultrasonication was used for the miniemulsification until making equilibrium and step by turbidness measuring. When DSC measurings was done it was observed that the dynamic crystallisation point of the synthesized polyester were shifted much down that crystallisation inside the droplets was supressed when polymerisation status applied. The runing point of dried polymer was determined by DSC method. Non-spherical sum was formed when crystallisation carried out at low temperature. The pH of the minemulsion shifted to 5-6 after polymerisation from 7.
5. Green Polymer Chemistry Using Nature’s Catalysts, Enzymes ( Pukas et.al, 2009 )
Enzymes are the natural accelerator. The usage of enzyme as a accelerator increases as replacement to chemical contact action method of organic synthesis. The advantage of enzyme were ability to run under mild status, high selectivity, biocompatibility and recyclability. The polymer synthesis was done by enzyme and the most common illustration are polycondensation, oxidative polymerization and pealing opening polymerisation. The usage of enzyme as a accelerator in polymer scientific discipline is of import methodological analysis for the synthesis of fresh polymeric construction, which are impossible or hard to fix.
3. CRITICAL REVIEW
The present paper is about the lipase catalysed synthesis of bio-based reactive polyester using itaconic anhydride as a renewable monomer. For cut downing C dioxide emanation polymeric stuff was produced from biobased renewable stuff. Therefore poly-lactic acid has been produced utilizing biobased renewable stuff. Work on the ring opening polymerisation utilizing enzyme accelerator was already done. The work on the lipase catalysed pealing opening polymerisation of dicarboxlyic acid was first done in 1993 for the ring opening add-on condensation polymerisation ( ROACP ) affecting desiccation already carried out.
The work on the “dehydration in water” utilizing lipase catalysed polymerisation to formed polyester in H2O was besides done. From the extension of an all these surveies the current paper include lipase catalysed synthesis reactive polyester using itaconic anhydride ( IAn ), succinic anhydride ( SAn ) or glutaric anhydride as get downing monomer with for glycol. Even though the construct was non new but the work done was fresh. The writer done the work with utilizing new monomer IAn and four glycol. ROACP between two monomer itaconic anhydride and glycol was non possible so the writer added one excess polymer so that reaction completed. Author carried out theoretical account reaction for acquiring information about the regioselectivity and substrate selectivity of itaconic anhydride utilizing n-octyl intoxicant.
3.2 TECHNICAL CORRECTNESS
Technically, this paper is about right. All the obtained consequences have been represented through limpid graphs.
All the employed methods have been well-described by the writers. This enabled easy and right reading of some of the related secret plans and enabled the apprehension of the associated constructs. The spectra included in the manuscript clearly represent the consequences obtained via assorted experiments and the theoretical treatment supports the consequences represented in these spectra ; which enabled better apprehension of the experiments and the constructs.
Flow OF EXPERIMENT
The flow of the experiments conducted is logical. In the initial portion of this paper, the scientists have given a brief debut about biobased renewable stuff. The writers used some mentions to province the method for poly lactide synthesis utilizing two method pealing opening polymerisation of lactide and direct polycondensation of lactic. Lipase catalysed pealing opening polymerisation of dicarboxylic acid anhydride affecting desiccation. The mention besides included the “dehydration in water” and have conducted green polymer chemical science. To the extension of these work done current paper utilised the itaconic anhydride as a starting biobased monomer to bring forth a poly ( lactic acid ) macromonomer.
The scheme of synthesis of biobased reactive polyester from itaconic anhydride was like that itaconic anhydride does non respond with diol entirely so it is necessary that the monomer added so that the reaction was completed hence succinic anhydride or glutaric anhydride was used in combination. During the synthesis all reaction were remained inhomogenous and gave merely low molecular weight merchandise with Mn values between 150 and 390 as determined by GPC analysis. The H? NMR surveies show that the itaconic anhydride was wholly consumed during pealing opening reaction. In add-on to these EIS-TOF MS analysis show that reaction of itaconic anhydride with diol reaction gives mixture of 1:1 and 2:1 adduct of IAn: glycol. From these it was conclude that in add-on to chief ROA reaction little extent of condensation and desiccation occurred.
After these analyze the writer pointed out why the itaconic anhydride entirely does non initialised expected pealing opening add-on condensation polymerisation reaction. The ground behind these was that itaconic anhydride is less reactive than succinic anhydride in dehydration measure. The writer gives the information from consequence that ROACP involves two different types of reaction a ROA between glycol and cyclic anhydride and desiccation condensation between carboxylic acid group and intoxicant group.
Author carried out theoretical account reaction before the survey of the ROACP reaction to obtain valuable information about the merchandise polyester construction and cardinal facets of itaconic anhydride. The theoretical account reaction carried out utilizing n-octanol alternatively of a glycol. The regioselectivity information obtained from reaction carried out with novoenzyme 435 accelerator without molecular screen in methylbenzene at 25°C. The writer interpreted from consequence that was obtained from H? NMR. The ?-selectivity value with lipase contact action was 49 % and without lipase contact action was 90 % and therefore show that reaction was governed by lipase contact action. Author besides focus on the substrate selectivity in the reactant in order to fix reactive polyester. The consequence from H? NMR surveies show that after 3h the IAn and SAn were 13 % and 27 % consumed severally and without lipase accelerator these reaction did non happen.
Author carried ROACP reaction under different status utilizing IAn, SAn and glycol. IAn: SAn: glycol were 2.5:2.5:5.0 and 1.4.0:5.0 taken for synthesis of polyester. When reaction carried out in without novoenzyme 435 no merchandise was formed which indissoluble in n-hexane. When the reaction carried out with the lipase but without the molecular screen, reaction system becomes homogeneous to synthesise polymeric merchandise with low MN.When the molecular screen were added ROACP was increased and gave the polyester with higher MeterNvalues. Out four glycol 1,8-octanediol was the most favorable glycol in footings of molecular weight, output and figure of units per molecule. Then paper ended with a elaborate treatment on assorted parametric quantities studied and consequences observed, which was followed by an appropriate decision.
In this paper, the writers have limpidly explained the background of the subject, which gives a clear tenet of the researched subject. Explanation of some constructs enables better apprehension of the experiments and reveals the authors’ logical attack towards the work conducted. Each of the sub-topics good describe the basic constructs covered within them. There is no repeat of affair. Therefore paper is moderately easy to follow and understand.
Writers have provided 38 mentions ; all the mentions have been cited in class of the treatment. All mentions are formatted as per guidelines mentioned for writers by the publishing houses of this scientific diary. Statements in paper can be right interpreted by mentioning to the cited mentions.
3.5 TITLE AND ABSTRACT
Title of the paper is“Green polymer chemical science: lipase catalysed synthesis of bio-based reactive polyester using itaconic anhydride as renewable monomer”. It is self-explanatory. By looking at the rubric we can acquire clear thought that the experiment includes synthesis of biobased reactive polyester utilizing itaconic anhydride as a renewable monomer and lipase as a natural accelerator.
The abstract of the paper presents an overview of the assorted surveies conducted in the manuscript and briefly nowadayss experimental model and the most of import consequences obtained by the writers. The abstract of paper is of appropriate length and sufficient to give clear thought about what work has been done. The abstract brings out all the chief points of paper.
3.6 ILLUSTRATION AND TABLES
The spectra and graphical representations every bit good as the tabular array represented in the paper are appropriate. The consequences discussed in the text are accurately represented in the graphs and spectra. They are self-explanatory and simple to understand. There seekers have provided the analytical information of stuff synthesized during their research. This included Mass spectra, proton NMR spectra and IR spectra of precursor stuff and intermediate synthesized to indicate out the differences between the assorted polymer synthesized during the work utilizing different combination of a monomer in different ratio utilizing different glycol and different reaction status as a cogent evidence of the polymer being synthesized varies harmonizing to a reaction status and monomer and its concentration.
No alternate reading can be made from the obtained consequences. All the decisions made by the writer are right and warrant the consequences obtained.
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- 29 Taden, A., Antonietti, M. & A ; Landfester, K. ( 2003 ). Enzymatic polymerisation towards biodegradable polyester nanoparticles. Macromol. Rapid Commun. 24, 512–516.
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