Effect of MAH Grafted Polymer on Impact Strength of Nylon

Toughened nylonis a kind of nylon modified material, which is a granular product formed by using nylon as a raw material to improve its toughness.Elastomer toughened nylonhas become one of the common toughening methods due to its ease of processing and low cost.

The purpose of toughening: to absorb the external energy in the process of destruction. Toughened nylon is based on a shear yielding mechanism. Toughness is relative. That means physical property is determined by certain conditions. There are many theoretical studies on elastomer-toughened nylon systems, among which the commonality and nature of brittle-ductile transitions are particularly important. Factors related to brittle-ductile transition of polymer: morphology, temperature, deformation rate, matrix and dispersed phase, interface viscosity, etc. The morphology includes: size, shape, content, dispersion of the particles. WU's particle spacing model is a good illustration of some of the principles. When the particle spacing is less than the critical particle spacing, it exhibits ductile fracture, and conversely, it will brittle fracture. The brittle-ductile transition temperature plays an important guiding role in the formulation of the toughened nylon system. The critical temperature is greater than the brittle-ductile transition temperature, and the material will be ductile fracture, and conversely, it will be brittle fracture. A thermoplastic polymer toughened with an elastomer must have a modulus that is less than one tenth of the modulus of the matrix will provide an effective toughening effect.

Through the study of the brittle-ductile transition of nylon 66/rubber blends with different interface strengths, it is found that the van der Waals interaction between the interfacial molecules of the system is sufficient while the interface bond strength is not required. What really determines the brittle-ductile transition is the particle spacing. Increasing the compatibility of the elastic toughening polymer on the brittle-ductile transition is mainly reflected in reducing the surface tension of the dispersed phase in the matrix. And increasing the dispersion of the elastomer, and reducing the size of the dispersed phase means reducing the particle spacing.