Part C Question 1 Addition polymerization In addition polymerization, polymer is formed by addition monomer without eliminating any product at specified temperature, pressure and presence of catalyst. Different methods of addition polymerization are free radical polymerization, cationic polymerization, anionic polymerization and coordination polymerization. Mainly addition polymerization occurs in the monomers having double bound. This process has three stages initiation, propagation, termination. Initiation: - free radicle attack monomer and form free radicle monomer this is called activated monomer. Propagation: - activated monomers react each other and form growing polymer chain. Termination: - the chain growth end at this stage. Condensation…
Polymerization is the process in which small molecules combine chemically to produce a large chain-like or network molecule (www.britannica.com). Through polymerization, a polymer is produced. A large number of small molecules react to produce a small number of large molecules. The reactant of polymerization is a monomer. Monomers, meaning "one part" or "one member," are small units that make up giant molecules (Exploring Giant Molecules). The product is a polymer. There are two main types of…
3.1 Effect of reaction time period The time course is a good indicator of catalyst performance and reaction progress. It helps pinpoint the adequate time necessary to obtain the best yield and minimize the process cost. Figure 1 shows the acid value profile of Sn(Oct)2 catalyzed synthesis of PRA. As the reaction progressed, the hydroxyl group of one monomer reacted with carboxylic group of another monomer to form oligomer and then the chain was lengthened to polymer. This was indicated by a…
This process has several distinct advantages. Besides being easy to control the thermal and viscosity problems of the other techniques, large decreases in the molecular weight of a polymer can be made without altering the polymerization rate by using chain transfer agents. However, large increases in molecular weight can only be made by decreasing the polymerization rate, by lowering the initiator concentration or lowering the reaction temperature. Emulsion polymerization is a unique process in…
Polymers are substances which have large number of repeating structural units repeated in the same type of linkage. The chemistry that deals about polymers is called polymer chemistry and the reaction is called as polymerization. Polymer chemistry have a wide range of application in day to day life and the research and recent advanced in this field are both industrially and academically notable and increasing day by day . In this review essay I am going to briefly discuss about polymerization.…
Polymerization is the synthesis of monomers using a catalyst (“Plastics”). The text describes the process of polymerization, “Each of these small molecules is known as a monomer ("one part") because it 's capable of joining with other monomers to form very long molecule chains called polymers ("many parts") during a chemical reaction called polymerization” (“Plastics”). During any one time in polymerization, millions of these polymer chains can be developed (“Plastics”). The product that results…
Enzymatic polymerization is one of the best alternative methods that can be used in synthesize PLA with better physical and chemical properties. This is an eco-friendly process, which can synthesize PLA in mild conditions. Polymerization process can be adjusted and controlled in this method [39]. Materials and Methods for PLA synthesis 85 wt% of purity Lactic acid was used in the polymerization process, and Stannous octoate (Sn(Oct)2) was used as the catalyst. The polymerization process was…
QUESTION: Give the Preparation, Properties and Applications of any four POLYMERS 1. Polyethenics ( Vinyl Resins) They are obtained by the polymerization of monomers containing the ethylenic bond (-C=C-) I. Polyethylene ( PE ) Polyethylene is one of the simplest and most inexpensive polymers. It is a waxy, chemical inert plastic. It a thermoplastic formed by the addition polymerization of ethylene. There are two types of polyethylene Low Density polyethylene (LDPE) By using free radical…
Current studies have found that taking omeprazole (prilosec) in combination with paclitaxel, will increase the effectiveness of paclitaxel as an anti-cancer agent. Paclitaxel is an effective form of cancer therapy that treats various kinds of cancer from ovarian to lung cancer. Paclitaxel works by promoting the polymerization of microtubules and prevents depolymerization to have a cytotoxic affect on cells (DeAngelis LM, et al., 1995). Omeprazole is a proton pump inhibitor used clinically for…
This polymerization is initiated by the free-radical initiators such as Alkyl Lithium compounds in the presence of stabilizers which serves as a deterioration preventive for the final product. In this process the water is entirely excluded. The process is homogeneous since all components are dissolved and this offers greater control over the process allowing fitting of the polymer. The free-radical initiators compound are sequentially added to monomers. Relative to Emulsion-SBR the Solution-SBR…