Nevertheless, polymers with degrees of polymerization determined by the ratio of the concentration of reacted monomer to the overall concentration of active species or of introduced initiator (DPn=A[M]/[I]o) have been 6 prepared with the narrow molecular weight distributions. Clipping is a handy way to collect important slides you want to go back to later. Often anionic polymerization involves living polymerizations, which allows control of structure and composition. Emulsion polymerization BULK POLYMERIZATION The simplest method of polymerization where the reaction mixture contains only the monomer and a monomer soluble initiator. For example, if a—a is a diacid and b—b is a diol: from diacid from diol. Let RMe be an organometalic compound such as butyl lithium (LiC 4 H 9) that initiates polymerization and M a monomer, then the individual steps can be … M= (DP) M 0. One way of measurement of conversion is the degree of polymerization represented as DP or Xn. POLYMERS Introduction to Polymers 2 3. Solvent may terminate the growing polymer chain, leading to low molecular weight polymers 4. Degree of polymerization. For instance, if a polymer P is made up of 5 numbers of monomers (M), then its degree of polymerisation will be 5. How is the Polymerization Reaction Classified? Polymerization is the process by which monomer molecules are reacted together in a chemical reaction to form a polymer chain (or three-dimensional networks). Polyacrylonitrile > 2000. the polymerization. This will depend only upon the initial and final states, not the nature of the intermediate (free radical, anion, cation). Now customize the name of a clipboard to store your clips. The … and M0 is the molecular weight of the monomer unit. (Because in reality polymers consists of chains of different length, the average value is used.) Initiation, propagation, and termination reactions have different rates and mechanisms. In 1984, Higashimura and Sawamoto reported the first living cationic polymerization for alkyl vinyl ethers. 1. Lecture 2.0 Polymerisation - Free download as Powerpoint Presentation (.ppt), PDF File (.pdf), Text File (.txt) or view presentation slides online. Transformer Oil and Degree of Polymerization of Solid insulation Sanjay.G.Patki, S.G.Patil, Jaspal. (2.25) 1 X ¯ n = K t K P [M] + K tr, M K P + K tr, S [S] K P [M] It can be seen that in cationic polymerizations, the number-average degree of polymerization is independent of initiator concentration. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. techniques Process conditions: Homogeneous polymerization: a) Bulk b) Solution 2. Malaviya National Institute Of Technology Jaipur, Polymer science: preparation and uses of polymers, No public clipboards found for this slide. DP is defined as the number of monomeric units in a polymer. Eq. The degree of polymerization, DP is the original number of molecules divided by the remaining number of molecules and approaches a number equal to the original number of molecules as N approaches one. If you continue browsing the site, you agree to the use of cookies on this website. Number average DP and weight average DP are the two main types used for measuring the DP. In other words, the distribution of how long your polymer chains are in your reaction must be very low. the degree of polymerization 2. Solution polymerization | PowerPoint PPT presentation | free to view . It can cause non availability of transformers for long hours. Disproportionation 3. Place 3.0 mL of liquefied phenol and 10 mL of 37% (by weight) aqueous formaldehyde solution in a 25 mL round-bottom flask. 8.45. SEMINAR ON. large molecule or a macromolecule which essentially is a combination of many subunits Also, the polymerization reactions for Nylon 6 and Spandex do not proceed by elimination of water or other small molecules. If you continue browsing the site, you agree to the use of cookies on this website. You need to … • To develop expressions for the average degree of polymerization and molecular weight distribution for anionic polymerization. Several Polycyclopentadiene molecules have two different kinds of double bonds for end groups and a complicated backbone of saturated fused rings. Polymerization of HbS and diGEE-HbS was carried out in 1.8 M potassium phosphate buffer, pH 7.2. Propagation proceeds through an alkoxide (anionic polymerization) or an ozonium (cationic polymerization): (1.4) (1.5) Chain transfer and complex termination steps arrest the chain propagation … Each reactive monomer goes on to react with other monomers to form a linear polymer. 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