7. Переведите отрывок на слух по предложению.
Branching of polymer chains also affect the supramolecular properties of polymers. Long chain branches may increase polymer strength and toughness, due to an increase in the number of entanglements per chain.
Short side chains may likewise reduce crystallinity due to disruption of the crystal structure. Reduced crystallinity may also be associated with increased transparency due to light scattering by small crystalline regions.
A good example of this effect is related to the range of physical attributes of polyethylene. High density polyethylene (HDPE) has a very low degree of branching, is quite stiff, and is used in applications such as milk jugs. Low density polyethylene (LDPE), on the other hand, has significant numbers of short branches, is quite flexible, and is used in applications such as plastic films.
The branching index of the polymer is a parameter that characterizes the effect of long-chain branches on the size of a branched macromolecule in solution.
8. Переведите предложения на русский язык письменно.
1. Tie molecule: a molecule that connects at least two different crystals.
2. Stem: a crystallized, sticklike portion of a polymer chain connected to non-sticklike portions, or chain ends.
3. Chain folding: the conformational feature in which a loop connects two parallel stems belonging to the same crystal.
4. Globular-chain crystal: a type of crystal comprised of macromolecules having globular conformation.
5. Dendrite: a crystalline body produced by skeletal growth, leading to a ‘tree-like’ supramolecular structure.
6. Fibrous crystal: a type of crystal significantly longer in one dimension than in either of the other two.
7. Shish-kebab structure: a polycrystalline structure consisting of fibrous crystals surrounded by lamellar crystals, the stems of which are parallel to the fiber axis.
8. Spherulite: a polycrystalline, roughly spherical morphology consisting of lath, fibrous or lamellar crystals emanating from a common centre.
9. Lath crystal: a lamellar crystal prevailingly extended along one lateral dimension.
10. Extended-chain crystal: a polymer crystal in which the chains are in an essentially fully extended conformation.
9. Переведите предложения на английский язык письменно.