An unknown polymer sample was found to have the following molecular weight distribution: Molecular weight range X; Wi 8,000 – 20,000 0.05 0.02 20,000 - 32,000 0.15 0.08 32,000 – 44,000 0.21 0.17 44,000 – 56,000 0.28 0.29 56,000 - 68,000 0.18 0.23 68,000 – 80,000 0.10 0.16 80,000 – 92,000 0.03 0.05 Which of the following common polymers is this sample? (This question has only one correct answer)

An unknown polymer sample was found to have the following molecular weight distribution: Molecular weight range X; Wi 8,000 – 20,000 0.05 0.02 20,000 - 32,000 0.15 0.08 32,000 – 44,000 0.21 0.17 44,000 – 56,000 0.28 0.29 56,000 - 68,000 0.18 0.23 68,000 – 80,000 0.10 0.16 80,000 – 92,000 0.03 0.05 Which of the following common polymers is this sample? (This question has only one correct answer)

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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An unknown polymer sample was found to have the following molecular weight distribution: Molecular weight range xi 8,000 -20,000 0.05 20,000 - 32,000 0.15 32,000 44,000 0.21 44,000 56,000 0.28 56,000 -68,000 0.18 68,000 - 80,000 0.10 80,000 - 92,000 0.03 Having a DP=763, which of the following common polymers is this sample? Select one: wi 0.02 0.08 0.17 0.29 0.23 0.16 0.05 a. Polymethylmethacrylate with a monomer molecular weight of 100.121 g/mol b. Polyvinyl chloride with a monomer molecular weight of 62.498 g/mol c. Polycarbonate with a monomer molecular weight of 61.0168 g/mol d. Polypropylene with a monomer molecular weight of 42.08 g/mol e. Polystyrene with a monomer molecular weight of 104.15 g/mol
Q2/ Determine the weight and number average molecular weights as well as degree of polymerization for the polypropylene materials. Number Range of Molecular weight in gram/mol and weight fractions X₁ W₁ 8000- 16000 0.05 0.02 16000- 24000 0.16 0.1 24000- 32000 0.24 0.2 32000- 40000 0.28 0.3 40000- 48000 0.20 0.27 48000- 56000 0.07 0.11
Q5 (a) Figure 6 shows two types of polymeric products fabricated using different processing techniques. Suggest with justification for the type of processes used to produce the products: i. Product A ii. Product B A B Figure 6. Two types of polymeric products (a) plastic bottles and (b) plastic car boot tray (b) The molecular weight data of a Polymer X are given in Table 3. Once undergone a melting process, it achieves degree of polymerization, DP of 498 upon solidification. i. Calculate the number-average molecular weight (Mn) for the polymer. ii. Calculate the molecular weight for monomers of the Polymer X. iii. Prove that the Polymer X is a polytetrafluoroethylene (PTFE) with chemical formula of (C2F4)n- Given the atomic weights for carbon, C is 12.011 g/mol and fluorine, F is 18.998 g/mol.
Question 5: The graph below gives a plot of force versus total sample length in a tensile test of a polymer. The sample is cylindrical, with an initial diameter of 1 cm and an initial length of 10 cm. From the data below, calculate the modulus, yield stress, yield strain, tensile strength, and % elongation. 1200 800 10 12 13 14 15 Lensth (cm) Force (N)
A polymer has creep behaviour that can be represented as a power law equation: e = 0 (Jo + Jit") where J, is 0.5 GPa1, J1 is 0.45 GPa's 0.3 and n is 0.3 (with t in seconds). A component of this material has the following applied stress history: There is no stress before t = 0 A positive (tensile) stress of 8 MPa is applied from t = 0 for 4 hours From t = 4 hours to 6 hours, the stress is compressive stress of 2 MPa The stress is then removed. What will the strain in the material be at t = 9 hours? Enter your value as a number to 4 decimal places. You have a 2% error margin with this.
Polymers C and D have the same chemical composition, but Polymer C has a 40% greater weight- average molecular weight (M. ) than Polymer D. Which of the following statements is likely true? It is impossible to predict based on the information given Polymer C will have a higher yield strength than Polymer D Polymers C and D will have similar yield strengths since the molecular weight does not affect strength Polymer D will have a higher yield strength than Polymer C
Question 2 Figure 2 shows the dependence of fatigue strength on testing cycles (S-N curve) of an acetal polymer. 60 50 40 30 20 10 104 105 106 107 108 Number of cycles to failure Figure 2 The S-N fatigue curve for an acetal polymer a. What is the fatigue strength, or maximum stress amplitude, at one million cycles of loading? b. An acetal polymer 30-cm-long bar with a diameter of 20 mm is designed to survive one million cycles of loading, what is the maximum allowable axial load that can be applied on one end of the bar? Magnitude of stress Reversal, MPa
9. A polymer sample with an original length of 10 cm and cross- sectional area of 1 cm² is subjected to a tensile test. The force applied to the sample is recorded at different elongations, and the following data is obtained: Force (N) Elongation (cm) 0 100 200 300 400 500 0 1 2 3 4 5 Using this data, calculate the modulus of the polymer sample in units of Pa.
Determine whether the first part of statement will INCREASE, DECREASE or have NO EFFECT in the second part of the statement. 1. If there is an increase in karat of gold, the strength will ______. 2. If there is an increase in crosslink of a linear polymer, then the degree of amorphousness will _____. 3. If there is an increase in polar groups, then the degree iof polymerization will _____.
d) A number of [0]s and [0,90]s CFRP test specimens were made from prepreg material with the following properties: Fibre strength, of = 3250 MPa Fibre modulus, E₁ = 195 GPa Matrix strength, m = 35 MPa Matrix modulus, Em = 3.8 GPa Volume fraction of fibres, Vf = 0.65 Calculate the tensile strength, oc, and the tensile modulus, Ec, in the 0° and 90° directions, using the simple "rule of mixtures" approach for both the [0]s and [0,90]s specimens.
An unknown polymer sample was found to have the following molecular weight distribution: Molecular weight range 8,000 - 20,000 20,000 - 32,000 32,000 - 44,000 44,000 - 56,000 56,000 - 68,000 68,000 -80,000 80,000 - 92,000 0.03 Knowing that the monomer is methyl methacrylate, which of the below is the number average degree of polymerization for this polymer sample? Select one: O a. O b. DP 476 O C. DP = 338 DP = 664 O d. DP 544 O e. DP = 801 Xi 0.05 0.15 0.21 0.28 0.18 0.10 Wi 0.02 0.08 0.17 0.29 0.23 0.16 0.05
Question 2 The following data relate to an injection moulding grade of a thermoplastic polymer. Determine whether this melt obeys the power law and if so, estimate the power law exponent n. Comment on your findings. Shear rate (s') Viscosity (Pa.s) 10 2590 100 2260 500 1370 1000 845 2000 525 5000 278 10000 175