Impact and Flexural Strength, and Fracture Morphology of Acrylic Resins With Impact Modifiers
Fernanda Faot*, Leonardo H V Panza, Renata C M Rodrigues Garcia, Altair Antoninha Del Bel Cury
Identifiers and Pagination:Year: 2009
First Page: 137
Last Page: 143
Publisher ID: TODENTJ-3-137
Article History:Received Date: 09/3/2009
Revision Received Date: 09/4/2009
Acceptance Date: 08/5/2009
Electronic publication date: 29/6/2009
Collection year: 2009
open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.
This study evaluated the impact and flexural strength and analyzed the fracture behavior of acrylic resins.
Eighteen rectangular specimens were fabricated of Lucitone 550, QC 20 (both unreinforced acrylic resins), Impact 1500 (extra strength impact), Impact 2000 (high impact) according to the manufacturers’ instructions. The impact strength was evaluated in notched specimens (50x6x4mm) and flexural strength in unotched (64x10x3.3mm), using three-point bending test, as well as, stress at yield, Young modulus and displacement at yield. Fragments from mechanical tests were observed by SEM. Data from impact strength, stress at yield and displacement at yield were analyzed by 1-way ANOVA and Tukey test (α=0.05). Young modulus values were analyzed by One-way ANOVA and Dunnett T3 multiple comparisons test (α=0.05).
Mean values of impact strength and stress at yield values were higher (P<.005) for Impact 2000 while Young modulus was higher (P<.05) for Lucitone 550; Impact 1500 and Impact 2000 showed significant values (P<.05) in the displacement at yield. Impact fractures of the all acrylic resins were brittle. Bending fractures of Lucitone 550 and Impact 2000 were brittle, QC 20 fractures were ductile and Impact 1500 showed brittle (75%) and ductile (25%) fractures.
Within the limitations of this study, the Impact 2000 showed improved mechanical properties with high capacity of stress absorption and energy dissipation before the fracture.