Study Of Toughened Organic Glass With High Transmittance

O_rganic glass has many excellent properties: has good transparency、chemicalstability and weather resistance, easy to stain, easy to processing, beautiful appearance.Compared with inorganic glass, PMMA has less weight, better processing adaptability,easy to make into varieties of shapes and colorful transparent products. Because theorganic glass has many advantages which other materials do not have, in recent year,PMMA has been widely applied to aviation, construction, agriculture, opticalinstruments and other fields. However, PMMA also exhibits low toughness, belongs tohard and brittle plastic material, which limits its use in some high-tech area applications.Thus, on the basic of keeping its good performance, the toughening of PMMA modifiedwith a far-reaching significance. O_n the basic of summarizing current research at homeand abroad on the method of toughening PMMA, the author investigated the followingexperiments: with Polypropylene glycol adipate、the block copolymer and Polyurethaneacrylates as toughening modifier of PMMA, then initialized and polymerized to producetoughening O_rganic glass with high transparency. The main contents and conclusionsare as follows:1. With the Adipic acid、1,2-Propanediol as raw materials, Polyethylene glycoladipate was synthesized by poly-condensation reaction, the structure of product werecharacterized by FTIR,GPC. The testing result shows that, the Polyethylene glycoladipate, with a low polydispersity, were synthesized successfully.PMMA was modified by addition of Polyethylene glycol adipate via insitu-polymerization. The mechanical properties、 optical performance and thermalproperty, were tested by impact testing machine、universal testing machine、DMA、Transmittance/Haze Tester and Comprehensive thermal analysis. Results show that, theaddition of Polyethylene glycol adipate exhibits a good toughening effect on PMMA,less effect on the tensile and optical transparency. The storage modulus and the glasstransition temperature decreased with increasing Polypropylene glycol adipate. Theimpact strength of the modified PMMA increases with increasing of Polyethyleneglycol adipate content. It can be improved by61.13%when the content of Polyethyleneglycol adipate reaches15%, the tensile strength decreased only6.33%. Transmittance ofPMMA virtually unchanged, Haze increased slightly by about1%. Tg result shows thatthe addition of Polypropylene glycol adipate improves thermal stability of resin matrix. 2. PMMA was modified by addition of block copolymer F68via insitu-polymerization. The mechanical properties, optical transparency and microstructure,were investigated, and the modification mechanism was discussed. The results showthat the addition of F68exhibits a good toughening effect on PMMA. The impactstrength of the modified PMMA increases with increasing of F68content. It can beimproved by117.61%when the content of block copolymer F68reaches20%. Withincreasing of F68content, the storage modulus of modified PMMA decreased first，andthen increased. The peak temperature of the loss factor decreased gradually. Theaddition of F68causes a leveling effect on the loss factor. The modified PMMA showspreferable optical transparency. The decrease of the light transmittance is less than2%when the content of F68is below20%.3. With Hexamethylene diisocyanate(HDI)、Polyether polyols、Acrylic hydroxyl ethylester as raw materials, Polyurethane acrylates pre-polymer has been synthesized bytwo-step method, the structure of Polyurethane acrylates was characterized by FTIR.The testing result shows that the reaction product is Polyurethane acrylates.PMMA was modified by addition of Polyurethane acrylates pre-polymer via insitu-polymerization. Impact properties、dynamic mechanical character and opticalproperty were tested by impact testing machine、DMA and Transmittance/Haze Tester.Results show that, the impact strength of the modified PMMA increases with increasingof Polyurethane acrylates content, and less effect in optical transparency. When thecontent of Polyurethane acrylates reaches20%, the impact strength can be reached to21.98J/cm2and improved66.77%, compared with pure PMMA. The storage modulusand the glass transition temperature decreased slowly, with increasing Polyurethaneacrylates content. The peak of the loss factor unchanged, corresponding Tg alsogradually reduced. The decrease of the light transmittance is less than3%when thecontent of Polyurethane acrylates is below20%, Haze increases slightly. Thermogravimetric analysis results show that the addition of Polyurethane acrylates improvesthermal stability of PMMA resin matrix.