A Study Of Surface Hardening Of PMMA

Improvement in abrasion resistance of PMMA is therefore desired in various fields. In this regard, tow approaches have been made in this paper. One is the abrasion-resistant coating, the other is a bulky cross-linking.(1) Both dipolysiloxane and terpolysiloxane have been prepared as silicone coating. Dipolysiloxane is synthesized by hydrolylsis and condensation reaction taking methyltriethoxy silicane and tetraethoxy silicone as the materials. When R/Si of the silicone resin is 0.85 and prepared dipolysiloxane with drop the solution of HCl, the best reaction condition is that the reaction temperature is 50℃and the pH of reaction solution is 3.Terpolysiloxane is synthesized by hydrolylsis and condensation reaction with methyltriethoxy silicane, tetraethoxy silicone and WD-V4. The optimal reaction condition is that the rate of R/Si is 0.77, the rate of H2O/-OC2H5 is 0.5, the reaction time is 3 hours. The best coating program is that the dipping time is 10~20 minute, drag velocity is 4mm/s. The best curing program is that the first curing temperature is about 30~50℃for half an hour, the second is heated to 80~90℃, maintain 80~90℃for 3 hours, the last is cool the sample with air.(2) Acrylate polymer modified with organosilicon is prepared using methyl methacrylate, butyl acrylate and the polysiloxane. The results show that the best sample is the T7 . The light transmittance of the coating sample with T7 is higher than the uncoated PMMA.(3) The copolymerization with acrylate has been investigated, and the optimal condition of the reaction is found as that the reaction temperature is 85℃, the catalyst load is 0.3%(mass fraction).The resultant copolymer'surface hardness is 3H. Crosslinking copolymer is synthesis by methyl methacrylate, acrylate and WD-V4. The optimal condition of the reaction is that the reaction temperature is 85℃, the catalyst is 0.3%(mass fraction).When the volume fracton of WD-V4 is 3%, the result of Crosslinking copolymer'surface hardness is 4H.