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

See similar textbooks

Similar questions

7
1) Assuming that the moduli and volume fractions of fiber and matrix materials are known, obtain the rule of mixtures in order to calculate the longitudinal Young's (elasticity) modulus of a unidirectional lamina by use of iso-strain assumption
( B ) A stress of 6.7 MPa is employed to one type of a polymer under constant strain . After 40 days at 20 ° C the stress is reduced to only 8.4 MPa . When the same polymer is heated to 40 ° C the relaxation time is 40 days . 1- Calculate the relaxation time constant for this material at 25 ° C ? 2- Estimate the stress after 50 days at 25 ° C ? 3- Estimate the stress relaxation activation energy for the same polymer .
A large-particle composite consisting of tungsten particles within a copper matrix is to be prepared. If the volume fractions of tungsten and copper are 0.84 and 0.16, respectively, estimate the upper limit for the specific stiffness of this composite given the data that follow. i Copper Tungsten GPa Specific Gravity Modulus of Elasticity (GPa) 8.9 19.3 110 407
8.42) Briefly explain how each of the following influences the tensile modulus of a semicrys- talline polymer and why: (a) molecular weight; (b) degree of crystallinity: (c) deformation by drawing; (d) annealing of an undeformed material; (e) annealing of a drawn material.
For a glass/epoxy lamina with a 70% fiber volume fraction using the properties in the tables provided below (a) Find the ultimate tensile strength. (b) Find the minimum and critical fiber volume fractions related to (a). (c) Find the compressive strength when the matrix undergoes extension mode and when the matrix undergoes shear mode, which one controls the compressive failure? Property Axial modulus Transverse modulus Axial Poisson's ratio Transverse Poisson's ratio Shear modulus Axial tensile strength Axial compressive strength Transverse tensile strength Transverse compressive strength Shear strength Epoxy Glass Units 3.4 85 GPa 3.4 85 GPa 0.3 0.20 0.3 0.20 1.308 35.42 GPa 72 1550 MPa 102 1550 MPa 72 1550 MPa 102 1550 MPa 34 35 MPa
During 650°C, the average grain diameter of a brass material was measured as a function of time, as seen below at two distinct points of Time (min) Grain Diameter (mm) 30 3.9 × 10^-2 90 6.6 × 10^-2 a. What was the grain diameter at the start? (orig diameter) b. What is the expected grain diameter after 150 minutes at 650 °C?
Please written by hand
Calculate the modulus of rigidity (shear modulus) of an epoxy resin if the modulus of elasticity (Young's modulus) E = 3.5 GPa and the Poisson's ratio = 0.35. Select one: a. G = 2.6 GPa b. G = 10 GPa c. G = 3.15 GPa d. G= 0.1 GPa e. G = 1.3 GPa
Question 1 A composite material consists of 40% parallel carbon fibres with a Young’s modulus of 405 GPa in a matrix of epoxy resin with a Young’s modulus of 2.5 GPa. Calculate the Young’s modulus of the composite in the parallel and in the perpendicular directions of the fibres. Use the graphical method seen in class to show the possible value of the overall young modulus of your composite material.
Question 6. Calculate the average molecular weight Mm for a thermoplastic that has the following weight fractions fi for the molecular weight ranges listed: Molecular Weight _fi 0.01 Molecular Weight Range (g/mol) 20,000-25,000 25,000-30,000 30,000-35,000 35,000-40,000 Range (g/mol) fi 0-5000 0.19 5000-10,000 0.04 0.21 0.15 10,000-15,000 15,000-20,000 0.16 0.17 0.07
A continuous and aligned fiber-reinforced composite having a cross-sectional area of 1200 mm² is subjected to an external tensile load. If the stresses sustained by the fiber and matrix phases are 152 and 2.27 MPa, respectively, the force sustained by the fiber phase is 72300 N, and the total longitudinal strain is 0.00143, determine the following: (a) The force sustained by the matrix phase (in N). i (b) The modulus of elasticity of the composite material in the longitudinal direction (in GPa). i N i (c) The modulus of elasticity for the fiber phase (in GPa). GPa i GPa (d) The modulus of elasticity for the matrix phase (in GPa). GPa