Influence of the rubber crosslinking density of a core–shell structure modifier on the properties of toughened poly(methyl methacrylate)

Abstract

Four kinds of core-shell structure acrylic impact modifiers (AIMs) with different rubber crosslinking densities were synthesized. The effects of the rubber crosslinking density of the AIMs on the crack initiation and propagation resistance and the mechanical properties of the AIM/poly(methyl methacrylate) (PMMA) blends were investigated, and we found that the maximum stress intensity factor, crack propagation energy, and Izod impact strength reached maximums when the appropriate rubber crosslinking density of AIM, 2.51 Â 10 25 crosslinks/m 3 , was adopted. Transmission electron microscopy photographs of the AIM/PMMA blends showed that the AIMs dispersed uniformly in the PMMA matrix. Meanwhile, through the analysis of optical photos and scanning electron microscopy of the impact fracture surface, we found that the deformation mechanism of the AIM/PMMA blends was local matrix shear yielding initiated by rubber particle cavitation of the AIM. The rubber of the AIM, whose crosslinking density was 2.51 Â 10 25 crosslinks/m 3 , was beneficial to the formation of intensive voids and initiated the local shear yielding of nearby modifiers of the PMMA matrix effectively in impact tests, which led to higher Izod impact strengths.

Study of the radical polymerization mechanism and its application in the preparation of high-performance PMMA by reactive extrusion

“…[14][15][16][17] Physical blending is one of the main methods for strengthening PMMA. Adding specic additives, like rubbers, 18 nanoparticles, 19,20 core-shell particles, 21,22 carbon nanotubes (CNT), 23 and graphene, 24,25 is common in the physical blending method. It should be noted that the compatibility of additives with the matrix is especially important, and poor compatibility can not only decrease the effectiveness of modication, but can even weaken the strength of polymers.…”

Synthesis of poly(butyl acrylate)‐poly(methyl methacrylate) core–shell nanomaterials of anti‐crease‐whitening properties

“…Such composite materials are widely used in various areas. For example, polymer–polymer core–shell particles can be used as effective structures for applications in pigments, fibers, immunological studies, drug delivery systems, baroplastic processing, toughening polymeric materials, transparent conductive thin films, coatings, and adhesives . The combined properties of core and shell polymers are superior to mechanical blends of those polymers.…”