Polymerization - Coursework Example

POLYMERIZATION and Question one a) Derivation of the equation of free radical polymerization -d[M]/dt = kp[M] (Kdf[I] / Kt)1/2 Polymerization kinetics Initiator fragments I2. 2I Rf = 2 fkd [I2] Chain initiation I + M M RI = KI [I] [M] Chain propagation MI + M M i+1 RP = KP [M] [M] Chain termination Mi + M i Inactive products RF = 2Kt [M]2 Overall rate of polymerization will be -d [M]/dt = ki [I] [M] + KP [M] [M] -d [M]/ dt = kp [M] [M] + [m]/dt = ki [I] [M] -d [M]/dt = 2Kt [M]2 D [M]/dt = ki [M] [I] – 2Kt [M]2 Ki [i] [m] is nearly or equal to 2Kt [M]2 Therefore combining the two reactions 2fkd [I2] = Ki [I] [M] Leading to – d [M]/dt = Kp [M] {fkd [I2]/ Kt}1/2 b) What is Kt Through the Arrhenius equation which is k = –Ea/ RT k - is t - A - constant. Therefore in order to calculate kt we will consider then equation 2k t [M]o2. This equation occurs after integration of –d [A] by [M] = [M]o – [M]o P = [M]o (1- P) and this is through substitution. Rp = kp [f kd [I]kt ]1/2[M] Rp = rp + ri = [ f kd [I]kt ]1/2[M] + 2 f kd [I] Rp = -rt = 2kt [f kd [I]kt ]1/2 Rp = [ kp2(f kd kt)1/2 ] [M][I]1/2 Therefore, the calculation will be 9.37 * 10- 4 = [107.3432 ( 0.7 * 1015.2 * kt) 1/2]] [3.14] [1.59 * 10-4] Question two Ethylene which when linked to form polyethylene is a low density plastic through additional polymerization. The result of adding many monomers of ethylene they will end up giving out polyethylene which is the polymer in question. CH2=CH2 ­_to –(CH2-CH2)n– The starting structure of the polymers is most likely to be a monomer. This is because monomers are the building blocks of polymers. A polyvinyl chloride polymer is formed from a vinyl chloride CH2=CHCl which when many of the link together through the additional polymerization they form polyvinyl chloride –(CH2-CHCl)n–. This element is usually a strong and rigid solid which is used in making pipes and even in plastering floors. These polymers formed through condensation polymerization. It is in the polymers that are in the amide group which mostly forms nylon as the final product which is the polymer for that case. ~[CO(CH2)4CO-NH(CH2)6NH]n~ polyamide or nylon 66 with the following components is formed by joining many of them in order to form a polymer of that nature. Question 3 These are the kinetics that is followed through the process. The method is known as the RAFT mechanism that mostly involves radical polymerization (Bernd 2000). The important factor that is required for this process is to have a monomer that is capable to undergo radical polymerization. RAFT polymerization is performed through the process of adding RAFT agent to free radical polymerization. The other requirements required for this reaction is the temperature, initiators, and solvents so that the process can continue to completion. During the polymerization process, an active site or active group is targeted which becomes the initiator of the polymer chain. For radical initiation step to occur the monomers that have the strong active sites such as double bonds between carbons suit best such as in vinyls, aldehydes and ketones. During the initiation step, one or two radicals are formed by the two monomers and secondly the molecules are transferred to the monomer units that are taking part in the process. During the free radical polymerization, there are three distinct parts that are endowed by the process. The initiator that involves thermal decomposition which leads to decomposition occurrence in order to produce radicals through heating. During this process, organic peroxides and azo compounds are used to facilitate the production of the radicals. This is the thermal decomposition. The second part is the photolysis part where metal iodides, alkyls and azo compounds are used in the production of double radicals. This occurs through the process of radiation. Thirdly the reduction oxidation reactions are employed so as to reduce hydrogen peroxide or an alkyl hydrogen by the use of any reducing agent such as iron copper and others. I fit were for the case the dissociation favor the reaction much This is where the persulfates are dissociated in the aqueous phase. Therefore, it will help in the emulsion polymerization in that it will diffuse the radical to the hydrophobic monomer containing the droplets. Ionizing radiation which through of . Then it is followed by the electrolysis process where the solution containing both the monomer and the electrolyte are introduced for electrolysis. Then there follows the plasma which i electrolysis at as low pressures as those used to make plasmas (Bernd 2000). Then the sonication and eventually to the tertiary initiator some as to conclude the initiation step. The second area is the initiator efficiency that helps in speeding the reaction to the propagation and product formation. This is where the primary recombination occurs for the starting the chain. All combination that takes place in the process do take place at this area whereby all other combination and even the side reaction all form from this part of the process. This is what eventually leads to the propagation step form any process of polymerization where the formation of products occurs. Propagation step The propagation is the point where the chain is made leading to the size of chain as per the monomers that were available for the reaction (Bernd 2000). This is the place where the reaction takes longer time that in all other areas of the reaction whereby it is the place where the chain occurs. This is the place where sigma and pie bonds emerge in the chain due to carbon - Carbon bonding present in the monomers. The carbon atom bonding with a free radical gives a more stable pie bond. Termination of chain formation will occur if there are no reagents for reaction and where the chain is free from contaminants. This is where all the reactants in the experiment have taken part in the reactions leading to the formation of chains. This is where the products of polymerization occurs leading to the formation of polymers such as Question four High temperatures will cause speeding up of the decomposition process in the initiator concentration leading to the increased rate of the reaction leading to build up of pressures by the system. The Tg decreases with the increasing temperature within the system of the reaction (Agnes 2010). The polymerization rate is also very strongly influenced by the size of the monomer side reactions which are of importance to the Tg of the copolymers. The Tg can be decreased through an increase in the reaction temperature. This is through increasing the rate of decomposition in the reaction leading to achieving the temperature that is high. This will facilitate the Tg whether its increase or decrease because this will be through regulation of the temperature. This is easy to achieve because regulation of temperature can be achieved easily. Optimum conditions should be achieved for any polymerization reaction that is the temperatures and the time due to the high value to the rate of polymerization and other properties of the final products for the reaction. Therefore in the copolymers given in order to achieve the Tg the temperature and the other conditions required in order to get the desired product in the copolymerization there must be an increase in the temperature of the reaction (Agnes 2010). But in case the Tg very high and it need lowered then this will be facilitated the decrease temperature order acquire the desired Tg This is a very important factor in any copolymerization that will ensure that the products reached are of the desired size and shape. The R-H group has the highest number of temperatures due to the bond that is exhibited between the hydrogen and carbon. For this reason the temperature required to break the bond and form an active site to attachment of the monomers it will require a lot of heat. For decomposition occur there must be a lot of heat for decomposing the carbon hydrogen bond. The R-CH3 group also needs a lot of heat to decompose it in the order form active sites for reactions to occur leading to better and enhanced reaction leading to the formation of better products. Aswegothegroupthedecompositionenergyreducesleadingbetterproductsandfasterattainmenttheproducts This will facilitate the rate at which the products are achieved. The bonding that is exhibited by different groups is very important and lead to the rate at which the reactants are converted to products. Therefore, the bonds that are exhibited by the reactants are directly proportional to the rate at which reactants will be converted to products. The reactivity to these polymers increase with the increase of the attachments and the side reactions that are within the polymer. Heat energy of decomposition required to decompose the polymers will be directly proportional to the chain size of the polymer (Fred 2011). Therefore in the copolymers given in order to achieve the Tg the temperature and the other conditions required in order to get the desired product in the copolymerization there must be an increase in the temperature of the reaction. But in case the Tg very high and it needs lowered then this will be facilitated the decrease temperature order acquire the desired Tg This is a very important factor in any copolymerization that will ensure that the products reached are of the desired size and shape. b) A copolymer composition that is capable of giving esters Tg of 49 degrees Celsius is Glycidyl methacrylate (GMA) which is an ester of methacrylic a monomer that in of epoxy . It has the following structure And the IUPAC name of the compound isOxiran-2- ylmethyl 2-methylprop-2-enoate. The molecular formulae C7H10O3 with a molar mass of 142.1546 g/mol. This can have a Tg of 49 degrees Celsius because it has a flash point temperature of 76 degrees Celsius therefore this means it has a Tg range of 46- 50 degrees Celsius. This will make it very appropriate for it to suit in that category. Question two A polyvinyl chloride polymer is formed from a vinyl chloride CH2=CHCl which when many of the link together through the additional polymerization they form polyvinyl chloride –(CH2-CHCl)n–. This element is usually a strong and rigid solid which is used in making pipes and even in plastering floors. These polymers formed through condensation polymerization. It is in the polymers that are in the amide group which mostly forms nylon as the final product which is the polymer for that case. ~[CO(CH2)4CO-NH(CH2)6NH]n~ polyamide or nylon 66 with the following components is formed by joining many of them in order to form a polymer of that nature Question five Application of Heat When heat is applied to the milk the property reduce leading to coagulation then returns to the usual structure. Heat increases the colloidal collisions leading to prolonged milk storage. This will have a good value because the components making the milk life is prolonged leading to better storage of the milk. ADDITION OF SALT On the addition of salt of salt to milk, this increases the repulsion reducing the colloidal stability. The electric repulsion between particles will automatically increase due to the introduction of a base to the milk leading to anion addition (Fred 2011). This will reduce the functional groups in the milk tampering with their structures. Adding Acid Addition of acid to milk gives an addition proton o the lipids and therefore stabilizing the fat globules in a process known as aggregation. This process will reduce the charge in the surface on the micelles casein. The micelle contains calcium phosphate but on addition of the acid the calcium phosphate becomes soluble living the casein structure to expand and bridging flocculation. Question six Size exclusion chromatography can also be described as gel permeation o molecular sieve chromatography. It works on the principle of analyzing molecules according to the size. It is very suitable to the high molecular weight species (Fred 2011). Polymers can be the most suitable for this case because of their high molecular weights and masses that make them very suitable for that case. For the success of the experiment, there must be a column and the packing materials and also a solvent that will enable the separation to occur. The solvent will passes through the column extracting the particles and leading to separation of the wanted particles. It is normally for preparing primary samples in the laboratory because it is a very reliable way of preparing pure samples. The solvent passes through the column adsorbing the samples and this is determined by the viscosity of the solvent (Fred 2011). The solvent must be primary. This means that the solvent must be very pure so that the results gotten can be good. This is because if the solvent to be involved in the separation is contaminated will give wrong results leading to unreliable conclusions. This is because from the first step the reagents used for the separation were not pure and hence the result itself will not be pure. The solvent for extraction should not react with the solute because in case they react not separation will occur and the experiment will not be suitable. The solvent should have low viscosity to ensure the retention time of separation is lowered leading to faster delivery of results (Stephen 2007). In data processing, the tabulation of results will be tabulated by software provided in the HPLC. But in the case where the samples to be analyzed were of large and have high molecular weights single types of detectors are used leading to better performance because the hplc does not always allow compatibility with the demands of the size exclusion chromatography always. There are components of size exclusion chromatography. The mobile phase is very limited in that they are the only solvents that can dissolve the samples. For this matter, the gel is ranked as the stationary phase where the mobile phase to be applied should not dissolve the gel but should only react with the sample components (Stephen 2007). The column to be used in the separation must be of the desirable length and should be of a dependable radius in order to enable the flow of the solvent extracting the samples in the column. The column should be water proof and it should not react with the sample so that the separation can occur only between the sample and solvent. The solvent should be able to react with the sample so that it can enable separation of the samples. Bibliography Agnes, F, M 2010. Effect of Heat to the Nutritive Nature of the Milk, Berkeley: University of California. Bernd, T 2000. Size Exclusion Chromatography of Polymers, Chincester: John Wiley & Sons Ltd. Fred, W, B 2011. Synthetic Polymers, USA: The University of Michigan. Stephen, D, B 2007. Polymers and Polymerization, USA: The University of Michigan. Read More