The Enhancer Screening Preparation And The Proportion Optimization In PMMA Enhanced Materials

Objective:PMMA(polymethyl methacrylate) has been widely used as a denture base material in clinical,because of less expensive,good biocompatibility and flexibility in machine-shaping.But some of its disadvantages,such as low material intensity,poor fatigue resistance,easy fracture and ageing,which often causes denture base(especially the maxillary complete denture) fracture,becomes large problem for clinical use.CNTs(carbon nanotubes)is a unique nanometer material, made up by curling black lead carbon atom.A lot of attention has been given to this material for its distinctive physical property,outstanding conductivity and stable chemical and physical properties.However,it has been extensive applyed to increase the strength of material,rather than medical material.This research means to perform a screening experiment by picking up different kinds of MWCNTs as intensifier to increase strengthen of PMMA and synthesizing them.The quantity of intensifier can be estimated by mechanical property test of the composite(MWCNTs/ PMMA).Methods:Referring to the GB/T16886 standard technical data,by using different Fe/HA,NI and Co produced MWCNTs as catalyst,then go through the cytotoxicity test in order to select the best catalyst.Specific as fellows:according to CVD (chemical vapour deposition),taking CH₄ as the carbon source gas to generate MWCNTs,purifying the products by the method of mixed acid ultrasonic purification.After that,the MWCNTs's shape can be analyzed under the scanning electron microscopy.MWCNTs/ PMMA compound material should be prepared by seperately mixing 0.1 mg,1 mg,2 mg MWCNTs with 15mL methyl methacrylate (MMA) according the method of Situ polymerization.By observing the feature through scanning electron microscopy and testing the mechanical behavior with the universal testing machine,the dose of intensifier MWCNTs can be decided and optimized,based on the comparison result with the products without intensifier.Results:1.MWCNTs with Ni activator has cell toxicity,comparing with Fe/HA and Co activator MWCNTs have no cell toxicity. 2.By using Fe/HA activator and CVD mothed can produce MWCNTs,by using the method of mixed acid ultrasonic purification can get high-purity MWCNTs.3.MWCNTs can improve PMMA mechanical performance,with increasing the proportion of MWCNTs,the tensile strength increases first and then decreases. According to the ratio adding 1mg MWCNTs into 15ml MMA,MWCNTs/ PMMA compound material's tensile strength and break elongation ratio reach a maximum, improved 9.4%and 28.6%respectively compare with resin which didn't add intensifier.Conclusions:1.MWCNTs made by Fe/HA and Co activator has no cell toxicity,and can be used as MWCNTs/ PMMA compound material's intensifier.2.Homogeneous MWCNTs can be made at 600℃,based on CVD(chemical vapour deposition) method,by using Fe/HA as activator,CH4 as the carbon source gas while H₂,Ar as an assist.Mixture acid treatment can purify the MWCNTs effectively.3.Prepared MWCNTs/ PMMA compound material according the method of Situ polymerization,and test the mechanical behavior by the universal testing machine, the results show that with the proportion of MWCNTs increasing,the tensile strength increases first and then decreases.According to the ratio,by adding lmg MWCNTs into 15ml MMA,MWCNTs/ PMMA compound material's tensile strength can reach to maximum,improved 9.4%compare with resin which didn't add intensifier.