A Model for Toughening of Semicrystalline Polymers

Abstract

Dispersing particles within a semicrystalline polymer can result in remarkable impact strength improvement and opens promising routes toward super-tough materials. Although the technique is extensively employed to modify polymer properties, predicting which dispersions yield toughness remains a challenging issue. By comparing the characteristic lengths and deformation processes involved in toughening, we explain why a minimum matrix confinement or ligament thickness is required to induce ductility. Our model was used to interpret experimental data and show how this critical confinement length depends on material properties, temperature, and processing history. Most importantly, it reveals an unexpected particle size effect. The predictions provide fresh insight into the design of toughened materials. The model also provides guidance to understanding the fracture mechanics of other complex systems such as composites or biological matter.

Crystalline organization and toughening: example of polyamide-12

“…These corrections particularly concerned the cross-section effect which tends to overestimate the number of small particles and the projection effect due to the non-zero thickness of ultrathin sections. Details of this image analysis are given in a separate study [26].…”

Realistic Numerical Analysis of a Bioinspired Layered Composite with a Crack: Robust Scaling Laws and Crack Arrest

“…[1,2] Accordingly various toughening mechanism of nacre have been proposed, [3][4][5][6][7][8] and nacre has bioinspired a number of remarkable materials. [9][10][11][12][13] Here, in particular, we focus on a simple model of nacre [14] that provides simple understandings of the type recently revealed for spider webs, [15][16][17] (although it does not include recently found complex structures beyond the layered structure [18,19] ). This is because simple scaling laws were obtained for the model to predict the correct order of the fracture energy of nacre, on the basis of analytical solutions for two crack problems.…”

Polymer Blend Compatibilization by Copolymers and Functional Polymers

“…particle size decreases exponentially and levels off at a given concentration. This behavior has been described extensively in the literature [49, 99,100] and can be explained by the change with time of the concentration of copolymer formed at the interface. To simulate the kinetics of this reaction, it is assumed that the concen tration, of the reactive groups at the interface is low, which means that the reactions at the interface end before the formation of a densely packed brush of copolymers.…”

“…The high BDTT is normally attributed to the existence of coarse ABS particles dispersed in the PBT matrix. Some authors have suggested that BDTT depends not only on particle size but also on interparticle distance, with a coarse morphology causing a larger interparticle distance [100][101][102][103][104][105][106][107]. Furthermore, there is evidence that the morphology of melt compounded PBT/ABS blends is unstable when they are injection molded [99].…”