Study On The Toughening Modification Of Cast PMMA Sheets

Toughening modification needs to be applied to cast PMMA sheets (organic glass) to satisfy special engineering requirements. In this thesis these toughening methods are systemically reviewed, which include: (1) co-polymerization with appropriate monomers; (2) blending with second-phase particles; (3) Inter-penetrating Polymer Networks structure (IPN); (4) bi-oriented extension process; and (5) fiber reinforcement technology. After studying the PMMA performances and the factors affected, the author investigated the following experiments: within MMA monomer, mixing commercial ACR impact-modifier and poly- (butyl actylate) rubber particles (PBA particles) synthesized from various polymerization methods, then initialized and polymerized with a special process to produce organic glass sheets~ The properties of sueh toughening modified PMMA sheets re tested and the toughening mechanism were deeply discussed based on TEM, SEM, ON: and UV-Vis system data. Study shows that (1) Blending with ACR impact-modifier is effective to improve the toughness of PMMA, with the highest impact strength of 12.23 kihn2 at 0. 15wt0/o content The impact lue will then decrease when surpassing this ACR content But the tensile strength and optical properties of the toughening modified PMMA may get a little mined. (2) By emulsion polymerization, solution polymerization, bulk polymerization and self- polymerization methods, the PBA paiticles are synthesized and blended into PMMA to achieve a significant increase of impact strength, among which the bulk polymerization PBA particles are the best The bulk PBA modified PMMA sheet shows an impact value of 16.60 kJ/m2, which is 500/0 higher than the original sheets, at lwt0/o. (3) By observing and analyzing ThM and SEM images of PBA particles and the fracture surface of PBA impact modified PMMA, the author holds that the cluster-structure of PBA dispersed in the PMMA matrix be the cause of toughening modification.