Toughened thermoplastics toughening mechanism

Toughening of BMIs with thermoplastics is a promising approach however, more information is required about the toughening mechanism involved in order to select the most promising polymers in terms of backbone chemistry, molecular weight, and reactive groups. 

An improvement in the toughness of thermosets can be favored by rubber or thermoplastic particles, which operate both in crack initiation and propagation mechanisms. The different toughening mechanisms can act simultaneously and can be modeled quantitatively. 

The aim of this work is to study the influence of particle size, interparticle distance, particle volume content, and local stress state on the toughening mechanism in several dispersed systems. The systems consist of a matrix of an amorphous or semicrystalline thermoplastic (see Figure 1). It is necessary to determine whether the particle diameter or the interparticle distance is of primary importance. But it is difficult to check the influence of both parameters because there is an interrelation between D, the average minimum value of A, and the particle volume content, t>P ... 

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Many amorphous thermoplastics are brittle, limiting their range of applications. Toughening with rubber is well known to enhance fracture resistance and toughness. Many major chemical industries are based on toughened plastics, such as ABS, HIPS and ionomers [30-34]. Important issues in the design of fracture resistant polymers are compatibility, deformation, toughening mechanisms and characterization. Particle size distribution and adhesion to the matrix must be determined by microscopy to develop structure-property relationships. 

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