Influence Of Matrix Composition Modification On The Toughening Of PMMA Resin

Poly(methyl methacrylate)(PMMA)is a typical rigid amorphous polymer,which is widely used in household appliances,electronic products,medical and automotive fields because of its excellent UV resistance and optical properties.However,its mechanical properties have obvious brittleness and notch sensitivity,so the research on toughening and modification of PMMA has attracted much attention.In this paper,PB-g-MMA core-shell particles have been prepared via an emulsion polymerization process with polybutadiene(PB)as core and polymethyl methacrylate(PMMA)as shell.The core-shell ratio was 80/20.PB-g-MMA core-shell particles were used to toughen PMMA.The low entanglement density of PMMA leads to crazing can be formed in fracture process of PMMA and it is difficult to achieve a high impact strength.Therefore,in this paper,the polycarbonate(PC)poly(vinylidene fluoride)(PVDF)was introduced into the PMMA matrix,to regulate the matrix chain entanglement density,which led to a better impact strength.The results indicated that in PMMA/PB-g-MMA blend system,when the PB-g-MMA content was 20 wt%,the PC content was 0%,the impact strength of PMMA blend increased from 9 J/m to 29 J/m.With the increase of the PC content,the impact toughness of the material improved.When PC content was 40wt%,the impact strength of blend was 51 J/m.The impact strength of the PMMA performance increased four times.On the other hand,MgO was added to the system,to promote the ester exchange reaction of PC and PMMA.The results showed higher impact toughness of the blend was achieved.Fracture mechanism showed that PB-g-MMA mainly toughened PMMA in crazing way.The introduction of the PC induced the shear yielding of the blend,which improved the toughness of the material.In the PMMA/PVDF system,when the content of PB-g-MMA was 20wt%,the impact strength of the blends was 30J/m.With the increase of PVDF content,the impact toughness of the matrix increased.The impact strength of the blends was 300J/m when the content of PVDF was 40wt%.The fracture mechanism showed that introduction of PVDF led to the occurrence of shear yielding,which absorbed a large amount of impact energy.The toughness of the material was improved.When the content of PVDF was 30wt%,the impact strength of the blends increased with the increase of the content of the core shell particles.Furthermore,When the content of PB-g-MMA was 30wt%,the impact strength of the blends was 350J/m.The toughening mechanism showed that the cavitation of the rubber particles and the shear yielding of the matrix were the reason of the ductile fracture of the material.Therefore,the introduction of PC or PVDF in the PMMA matrix,improved the toughening efficiency of PB-g-MMA for PMMA resin.The PMMA blend materials,with higher impact toughness were obtained.