ABSTRACT
When a chemist or a chemical engineer looks at a polymer, he or she sees a molecular structure with atoms, C—C bonds, chains, branches, cross-links, and crystals. However, when a design engineer looks at a polymer, he or she sees a mechanism with springs, dashpots, and sliding blocks. For example, if we were to draw a box around an element of material, one can imagine that within that box there is a spring as in Figure 3.1a, or a dashpot (viscous damper) as in Figure 3.1b. These two models represent a linear elastic solid and a linear viscous fluid, respectively. For the first, the linear elastic solid, the σ(ε) relationship is linearly dependent upon strain Mechanical models of the linear solid and the linear fluid. (a) Linear elastic solid (8 < 1, <italic>T</italic> < <italic>T<sub>g</sub> </italic>) and (b) linear elastic fluid (8 > 1, <italic>T</italic> > <italic>T<sub>g</sub> </italic>). https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429107214/0637e851-038e-4254-a272-a6a5c7665813/content/fig3_1.tif"/> () σ = E ε . https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429107214/0637e851-038e-4254-a272-a6a5c7665813/content/eq88.tif"/>
