Polymer Physics

PTFE shows a high melting point because of the strong interactions between polar CF 2 groups. The discussion above focuses only ...

In contrast, in 1966, Colson and Eby assumed that the comonomer B could enter the crystalline phase of A, with the mole fraction ...

10.3.2 Unit Cells of Polymer Crystals Let us first look at the unit cell structure of polymer crystals. The periodic lattice str ...

regarded as H2/1 helix. Therefore, the most stable internal rotation for a helical conformation determines the symmetric structu ...

monoclinic crystal series are the most common, occupying about two-third of the total. The trigonal, the tetragonal and the hexa ...

identical to the chain axis appears much smaller than the chain length, so he proposed theadjacent chain-folding modelto explain ...

kinetic selection is also called the chain-folding principle of polymer crystalliza- tion, as illustrated in Fig.10.12. Since th ...

Here assumes that Tm^0  Dh Ds (10.23) whereDhis the heat of fusion in each unit of volume, andDsis the melting entropy in each ...

crystal planes, and the minimum lattice energy can be obtained from the growth on this crystal plane. Therefore, its advancing s ...

Spherulites If we take the radiation-growing axialites at high temperatures as the dominant lamellae, and the empty spacing is ...

kind of spherulites obtained by direct branching growth at low temperatures, called thetype-II spherulites, as illustrated also ...

crystals. Such a shish-kebab-like crystal morphology is often calledshish-kebab crystals. As illustrated in Fig.10.19, with an i ...

The highly oriented polymer chains in the fiber crystal bring high strength to the fiber materials. The famous Kevlar fiber is h ...

DG¼ 4 p 3 r^3 Dgþ 4 pr^2 s (10.25) This equation is similar with (9.43). One can derive the critical free energy barrier for th ...

nucleation contains the lowest free energy barrier, and thus be the fastest, so it is not easy to be observed as the rate-determ ...

the PET transparency and Coke bottles. High transparency does not mean that there is no crystalline domain in materials. As a ma ...

activation energy for short-distance diffusion of molecules at interfaces, the lower the temperature, the smaller the crystal nu ...

G¼GgrowthGmelting¼Ggrowthð 1  Gmelting Ggrowth Þ¼Ggrowthð 1 exp DF kT Þ GgrowthDFGgrowthðllminÞ Df kT ð 10 : 29 Þ Here, t ...

shaped lamellar growth front of PE crystals can be directly observed in the bulk phase, as shown in Fig.10.28(Mullin and Hobbs 2 ...

The latter is also calledthe kinetic crystallinitythat can be measured by tracing the crystallization process with dilatometer, ...