Mechanical properties of polymers and composites-Nielsen Episode 2 pot

... have traditionally been the most popular and universally used of alt mechanical tests and are described by ASTM standard Vests such as D638, D8 82, and D4 12. These tests can be more difficult to ... bewildering number of mechanical tests and testing instru- m ents. Most of these tests are very specialized and have not been officially recognized as standardized tests....

Ngày tải lên: 13/08/2014, 16:21

... molecular weight and branching 26 5 I. Effect of cross-linking 26 8 J. Relationships and inlcraclJQrtS 27 7 K. Effect of erysNsllinity 28 0 U. Hffects of ptusticizHtion and cbpotynteri^ifbti 28 3 M. Molecular ... Comprcssioii and shear versus tensile tests: Rigid polymers 24 9 E. Effect of temperature 25 3 F. Rale of testing and the failure envelope 25 6 G. Effec...

Ngày tải lên: 13/08/2014, 16:21

... Tg value of poly(vinyl acetate) at the rate of 0. ,22 K'MPa (0 .22 C/atm). The' Tg value of polyfvinyl chloride) increases by 0.14 K/MPn (f).()14 fi C/atm). while the rate of increase ... value of Tg for infinite molecular weight, in the 22 Chapter 1 value of plnsticized polymers is then given by (51.96)' Equation ( 4 1 ) becomes equation (38) if K = 1. and...

Ngày tải lên: 13/08/2014, 16:21

... Testing and Materials. Phil- adelphia. 17. I). Telfair and U. K. Nason, Mod. Plastics, 20 , 85 (July 194.1). 15. D. R. Morey. Iml. EnR. Chem 37. 25 5 (1945). W. ASTM Standards DIH 22- 6H and D22H9-W, ... I), Ferry. Viscoelastic properties of Polymers, 3rd ed., Wiley. New York, 1980. 4. I , n, Nielsen. Mechanical Properties of Polymers. Van Nostrand Reinhold, New York...

Ngày tải lên: 13/08/2014, 16:21

... all directions. Unoriented amorphous polymers and annealed glasses are examples of such materials. They have only one of each of the three kinds of moduli, and since the moduli are interrelated, ... density of the material making up the beam of total mass m, P the period of the oscillation, f H the frequency of the vibrations in hertz or cycles per second, and / the r...

Ngày tải lên: 13/08/2014, 16:21

... type of polymer or copolymer), molecular weight and molecular weight distribution, degree of cross-linking, and of Plasticization. For two-phase and multiphase systems such as semi- crystalline polymers ... temperature and frequency and of changes in the nature of the pol- ymer is closely tied ty) T K and £ ( , A ,, which set the location of the transition zone in p...

Ngày tải lên: 13/08/2014, 16:21

... effect of any change in £ ()jr Copolymers and plasticized materials often show another effect—a broadening of the transition region with a decrease in the slope of the modulus curve in the region of ... plateau. Plasticizers and Copolymerization also shift the glass transition responses of the amorphous phase of crystalline polymers. In addition, the degree of Crystallinity...

Ngày tải lên: 13/08/2014, 16:21

... elongation comes from the spring E 2 and dashpot T] 2 , in parallel, and from the dashpot with the viscosity r\ ? . The total elongation Figure 2 Stress relaxation of a Maxwell model on a logarithmic ... which consists of a Hookean spring and a Newtonian dashpot in series as shown in the insert in Figure 1. The modulus or stiffness of the spring is E, and the viscosity of...

Ngày tải lên: 13/08/2014, 16:21

... superposition principle were made by Ferry, who made the process explicit (25 ); by Tobolsky (6 ,26 ); and by Williams, Landel, and Ferry (1 ,27 ), who showed that the reference temperature is not arbitrary ... ratio of a viscosity to a modulus, as in the spring-dashpot model of Figure 1, but each sprint! has the same (shear) modulus, and the steady-flow viscosity T] of equation (...

Ngày tải lên: 13/08/2014, 16:21

... of 0.980. Reid (80,81) has suggested that for rigid amorphous polymers. should be proportional may be related to the . For brittle polymers, the value of to onset of crazing. Equations ( 32) and ... nitrogen. Annealing can reduce the creep of crystalline polymers in the same manner as for glassy polymers (89,94,1 02) . For example, the properties of a quenched specimen o...

Ngày tải lên: 13/08/2014, 16:21