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How does increasing the degree of crystallinity of a semicrystalline polymer affect its tensile strength?

(b) Increasing the degree of crystallinity of a semicrystalline polymer leads to an enhancement of the tensile strength. Again, this is due to enhanced interchain bonding and forces; in response to applied stresses, interchain motions are thus inhibited.

How does molecular weight affect tensile strength?

In general, as molecular weight increase the strength, toughness and chemical stress crack resistance increase. A High molecular weight increases the chemical resistance – to a point. It takes more damage to the main chains of the molecules before it will affect the strength of the material.

How does deformation by drawing of a semicrystalline polymer affect its tensile strength decreases increases?

Deformation by drawing increases the tensile strength of a semicrystalline polymer. This effect is due to the highly oriented chain structure that is produced by drawing, which gives rise to higher interchain secondary bonding forces.

Do you expect amorphous or semi crystalline polymers to have higher thermal conductivities?

Semi-crystalline polymers have been shown to have greatly increased thermal conductivity compared to amorphous bulk polymers due to effective heat conduction along the covalent bonds of the backbone.

Why do polymers have low thermal conductivity?

Polymers are made up of strong covalent bonds and weak van der Waals forces in intra-chain and inter-chain molecular bonding, respectively. These modes have both lower frequencies and group velocities because of the weaker van der Waals stiffness resulting into lower thermal conductivity.

Why does metallic conductance decrease with increase in temperature?

The electrical conductivity of a metal decreases with the rise in temperature because the positively charged kernels present in the electron sea also acquire mobility and obstruct the movement of valence electrons responsible for conductivity.

Why does conductance increase with temperature?

In metals, conductivity is due to movement of free electrons. When temperature increases, the vibration of metal ions increases. In electrolytic conductors, the ions are charge carriers and with increase in temperature, ionization increases and hence, conductivity increases.

What is the effect of temperature on metallic conductor?

A metals electrical conductivity increases with decrease in temperature and decreases with increase in temperature. As it cools down, there is no hindrance in the form of thermal excitation, enabling easier flow of carriers, increasing conductivity.

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Are magnetic balls illegal in Canada?

The proposed mandatory requirements for magnetic children’s toys do not affect the current prohibition on dangerous novelty magnet sets. These items will remain banned in Canada.