Mechanical properties of polymers and composites-Nielsen Episode 4 pdf

... Intersaence, New York. 1 948 . 3. J I), Ferry. Viscoelastic properties of Polymers, 3rd ed., Wiley. New York, 1980. 4. I , n, Nielsen. Mechanical Properties of Polymers. Van Nostrand Reinhold, New ... points of many common polymers. More complete tables of melting points and heats of fusions may be found in Refs. 4, 38, 140 , and 141 . Chemical structure factor...

Ngày tải lên: 13/08/2014, 16:21

... bibliographical references and index. ISBN 0-8 247 -89 64- 4 1. Polymers Mechanical properties. 2. Polymeric composites— Mechanical properties. I. Landel. Robert F. II. Title. III. Series: Mechanical engineering ... all of the major mechanical properties of polymers: l_ Molecular weight 2. Cross-linking and branching 3. Crystallinity and crystal morphology 4....

Ngày tải lên: 13/08/2014, 16:21

... 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. Some of these tests, however, ... variety of units are used in reporting values of mechanical tests. Stresses, moduli of elasticity, and other properties are given in such units as MK.S (SI), cgs,...

Ngày tải lên: 13/08/2014, 16:21

... coefficient of expansion above T s and ag i is the coefficient below Tg for many polymers\ a A = 4. 8 x 10 4 K^-1. The Tg Mechanical Tests and Polymer Transitions 17 ambiguous and soundest ... unsymmetrical polymers. Thus syndiotactic and isoitactic poly( methyl methacrylate) have Tg values of 115 and 45 C respectively. The flexibility and cohesive energy density...

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, ... exactly 90° out of phase with the strain. Since the in-phase component is exactly analogous to thaj of a spring, and the out -of- phase component to that of a viscous respons...

Ngày tải lên: 13/08/2014, 16:21

... the normally rubbery 44 Chapter 2 detailed comparisons of the responses of a set of polymers (7,16, 54- 56). These frequency/time response curves serve to delineate the effects of changes in backbone ... type of polymer or copolymer), molecular weight and molecular weight distribution, degree of cross-linking, and of Plasticization. For two-phase and multiphase systems...

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

... However, the molecular theories of Viscoelasticity of polymers as 64 Chapter 3 especially if electronic or optical strain gages are used properly to measure the longitudinal and lateral strain. Unfortunately, ... used. When the stresses and strains become large and the stress-strain curve becomes nonlinear, simple descriptions of the response and interconversions between cre...

Ngày tải lên: 13/08/2014, 16:21

... of pounds per square inch and is in seconds. Doubling the load after 40 0 s gives a total creep that is the superposition of the original creep curve shifted by 40 0 s on top of the extension of ... amorphous polymers is or. less accurately, using the average value of Au from many polymers, of 4. S x H) ' K \ is the difference between the liquid and glassy volumetri...

Ngày tải lên: 13/08/2014, 16:21

... nitrogen. Annealing can reduce the creep of crystalline polymers in the same manner as for glassy polymers (89, 94, 102). For example, the properties of a quenched specimen of low-density polyethylene will ... independence of strain and time, for SBR (up to very large strains) and a polyurethanc rubber, llavsky and Prins (60) and co-workers have presented similar explici...

Ngày tải lên: 13/08/2014, 16:21