Briefly explain how each of the following influence the tens

Briefly explain how each of the following influence the tensile or yield strength of a semi-crystalline polymer and why: molecular weight degree of crystallinity deformation by drawing annealing of an undeformed material

Solution

Solution(a) Molecular weight

               The tensile modulus is not directly influenced by a polymer\'s molecular weight.

Solution(b)   Degree of crystallinity

         Tensile modulus increases with increasing degree of crystallinity for semicrystalline polymers. This is due to enhanced secondary interchain bonding which results from adjacent aligned chain segments as percent crystallinity increases. This enhanced interchain bonding inhibits relative interchain motion

Solution(c) Deformation by drawing

Deformation by drawing also increases the tensile modulus. The reason for this is that drawing produces a highly oriented molecular structure, and a relatively high degree of interchain secondary bonding.

Solution(c) Annealing of an undeformed material

When an undeformed semicrystalline polymer is annealed below its melting temperature, the tensile modulus increases