Poly correlation between crystalline

Relationship Between Molecular Structure and Composition of Poly(ethylene-co-p-MS) Copolymers. From above discussion, we have shown that poly(ethylene-co-p-MS) copolymers with a wide range of compositions can be achieved by varying the p-MS monomer concentration in the feed. To fully understand the properties of this new class of materials, it is very important to know the correlation between the copolymer compositions and their molecular structures. In this section, we focus on the effect of p-MS concentration on molecular weight, molecular weight distribution, melting point (Tm), crystallinity and glass transition temperature (Tg) of the copolymer. A series of copolymers with various p-MS concentrations were analyzed by GPC and DSC. 

El-Hadi, A., Schnabel, R., Straube, E., Muller, G., Henning, S., Correlation between degree of crystallinity, morphology, glass temperature, mechanical properties and biodegradation of poly(3-hydroxyalkanoate) PHAs and their blends. 6, 665-674 (2002), DOI ... 

For many thermoplastics there exist a mostly linear correlation between hardness and crystallinity. This is a result of the mixing rule of the hardnesses of the crystalline and the amorphous phase of the given poly-mer. Figure 4.197 shows the increase of hardness with increasing density, i.e. with higher crystallinity. 

The majority of these studies has been done on homopolymers. A recent study using blends of two polymers reported [56] that blends of poly(3-octylthio-phene) and poly(3-hexylthiophene) have a characteristic temperature of thermochromism that correlates in a linear way with the lamellar distance found in x-ray diffraction. These blends are partially crystalline with a lamellar distance intermediate between that of the homopolymers, but not in a simple linear manner. It is argued that this indicates that the side chains act primarily as spacers between the chains, and that melting of the main chains is essential to the thermochromism. As thermochromism is not limited to the crystalline phase, the argument has certainly to be extended to the amorphous phase, where no such simple description of geometry can be given. 

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