Amorphous PTFE has the same repeat atomic structure as the crystalline domains but without significant order. Another popular brand name of PTFE is Syncolon by Synco Chemical Corporation. Outstanding properties include weatherability and scratch resistance. It is available commercially in both pellet and sheet form. Department of Bioresource Engineering Assignment #2 BREE216: Bioresource Engineering Materials Question 1: Compute the repeat unit molecular weights for the following: a) polytetrafluoroethylene; b) poly-methyl-methacrylate; c) nylon 6,6 d) poly-ethylene-terephthalate. Poly(tetrafluoroethene) (PTFE) and other fluorinated polymers are used in: • cable insulation for electronics including aerospace • reactor and plant equipment linings, when reactants or products are highly corrosive to ordinary materials such as steel Repeat Unit. In many ways PFA is similar to FEP but generally has better mechanical properties at higher temperatures and a maximum service temperature very similar to that of PTFE. The well-known brand name of PTFE-based formulas is Teflon by Chemours. Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. The These are calculated below: For polytetrafluoroethylene the repeat unit molecular weight is just m 2 A C 4 from ENME 250 at University of Maryland (b) Determine the number-average molar mass of the sample. Polytetrafluoroethylene (Teflon) has a repeat unit with the formula F 2 C—CF 2. The repeat unit of PFA is shown below: C F F C F F n C F F C OC 3 F 7 F 0.01n PFA PFA was first produced by DuPont in 1972 (Teflon® PFA) and is also melt-processable. repeat unit [12, 16]. The crystal structure of polytetrafluoroethylene (PTFE), –(CF 2) n –, is unusual in having a number of crystal forms and also possessing substantial molecular motion within the crystal well below the melting point. Thus the molecular masses of both monomer and unit are identical at 28. (a) Compute the repeat unit molecular weight of polypropylene. Polytetrafluoroethylene (PTFE) is a highly crystalline polymer which is very resistant to attack by corrosives and solvents. Polytetrafluoroethylene (Teflon) has a repeat unit with the formula F2C—CF2 fraction 1 = 273 average of repeat units amount (mol) of polymer = 0.10 Molecular mass = 100.0156? (b) Compute the number-average molecular weight for a polypropylene for which the degree of polymerization is 15,000 1(c) in which isolated crystalline domains on the order of 5 to 20 μm are connected by amorphous polymer (image obtained by tapping mode AFM [17]). … Since there are two carbon atoms per repeat unit, there are two C—C chain bonds per repeat unit, which means that the total number of chain bonds in the molecule, N, is just (2)(5000) = 10,000 bonds. 14.3 Mer weights for several polymers are asked for in this problem. of repeat units Amount (mol of polymer 273 330 368 483 525 575 mount (mol) of polymer 0.10 0.40 1.00 0.70 0.30 0.10 2 4 5 6 Determine the molar mass of fraction 2 in units of g/mol. Known by such trademarks as Teflon, Fluon, Hostaflon, and Polyflon, PTFE is distinguished by its slippery surface, high melting point, and resistance to attack by almost all chemicals. C 5 H 8 O 2. For Polytetrafluoroethylene , each repeat unit consists of two carbon and four fluorine. (a) For polytetrafluoroethylene, each mer unit consists of two carbons and four fluorines (Table 14.3). Chlorine 35.45 g/mol .
The difference between the monomer and the repeat unit is the loss of the double bond in the former to give the chain-linked repeating group. The styrene repeat unit contains 8 Carbon atoms and 8 Hydrogen atoms. A sample of the polymer consists of fractions with the following distribution of chains: (a) Determine the molar mass of each fraction. A sample of the polymer consists of fractions with the following distribution of chains: Fraction Average no. If A C and A F represent the atomic weights of carbon and fluorine, respectively, then m = 2(AC) + 4(AF) The repeat units of a range of polymers together with the monomer units from which they are derived are shown in Table 3. Polytetrafluoroethylene (Teflon) has a repeat unit with the formula F2CCF2. It is similar to polytetrafluoroethene (PTFE), except that it is a homopolymer of the monomer chlorotrifluoroethylene (CTFE) instead of tetrafluoroethene. It also has extremely good thermal resistance at temperatures up to 250C. The simplest repeat unit is that for polyethylene, and consists of two carbon atoms linked to four hydrogen atoms. (a) For polytetrafluoroethylene, each repeat unit consists of two carbon atoms and four fluorine atoms. It has the lowest water vapor transmission … The semi-crystalline nature of PTFE is illustrated in Fig. Now, using Equation 14.7, it is possible to calculate the repeat unit weight of the unknown repeat unit type, mx. Thus mx = m − feme fx = 45.25 g/mol - (0.5)(28.05 g/mol) 0.5 = 62.45 g/mol Finally, it is necessary to calculate the repeat unit molecular weights for each of the possible other repeat unit types.