Study Of Preparation Of Toughened Polymethyl Methacrylate With High Transmittance

PMMA(organic glass) has such excellent properties as high light transmittance, colorlessness, chemical resistance, and dimensional stability. However, it has a poor impact resistance or brittle. Considerable attempts had been made to modify the macromolecular structure or phase structure to improve the impact resistance (toughening modification) of PMMA to satisfy special engineering requirements.Copolymers of St-MMA-AN by twos were synthesized to ascertain the relation of refractive indices and composing of copolymers in order to design the toughening particle to preserve transmittance of PMMA.In this thesis these toughening methods are systemically reviewed, which include:(1) copolymerization with appropriate monomer; (2) blending with second phase particles; (3) Interpenetrating Polymer Networks structure(IPN); (4) bioriented extension process; and (5) fiber reinforcement technology. After studying the PMMA performances and the factors affected, the author investigated the following experiments: (1) with PMMA resin, mixing ACR( PMMA/P(BA-St)/PMMA) impact-modifies synthesized by author from semicontinuous polymerization methods then molded with a special process to produce organic glass sheets; (2) PMMA/P(BA-St)/PMMA composite resin synthesized by author from in-situ polymerization methods then molded with a special process to produce organic glass sheets without mix.Study shows that: (1)The refractive indices of copolymer of St, MM A, AN by twos from bulk polymerization can be predicted by group contribution techniques. But deflection is relative big when the polarity of comonomer is strong. (2) PMMA composite resin synthesized by in-situ polymerization have good toughness and the toughness increasing with content of toughening particle without losing transmittance. But the tensile strength of the toughing modified PMMA may get a little ruined. (3) By observing and analyzing TEM and SEM images of PBA particles and the fracture surface of PBA impact modified PMMA, the author holds that the emulsion particles have regular core-shell structure and the toughening particles were uniformly dispersed in the PMMA matrix.