Preparation And Characterizations Of Polyethylene/Barium Sulfate Nanocomposites

In recent years, the T-shape copper intrauterine devices （Cu-IUDs） are one of the mostwidely used forms of reversible contraception for birth control. The T-shape plastic stents ofthe Cu-IUDs are PE composites. However, some side effects of the existing Cu-IUDs havenot been overcome in clinical use. The side effects directly related to the position of Cu-IUDin the uterus is correct or not. In clinical diagnosis, we usually check the position of Cu-IUDin the uterus through the X-ray. So we develop a novel T-shape plastic stents which can X-raydeveloping in order to check the position of Cu-IUD. However, due to a large number ofBaSO₄inorganic fillers added to this composite material, the T-shape plastic stents easy tobreak in the clinical application, resulting in T-type copper IUD failure. In order to solve theproblem of the clinical applications, a series of polyethylene/barium sulfate compositematerials were studied.A series of X-ray developing PE/BaSO₄composites were researched. The Stearic acidand aluminium coupling agent were applied to the surface modification of BaSO₄. The effectsof content of BaSO₄ , and kind and content of coupling agent on mechanical property anddisperse ability of PE/BaSO₄ composite were studied.The nanocomposites have beenanalyzed by means of SEM, WXRD, FI-IR and tensile and flexural tests. Our mainlyaccomplishments are as follows:1. The BaSO₄nanoparticles were synthesized by Na2SO4and BaCl2solutions, usingEDTA as complexing agent. The pH of solution was adjusted to 6 at 45℃. The SEMmicrograpH shows that BaSO₄were spHerical particles with the size of about 50 nm.2. The results indicated that stearic acid adsorbed on the surface of BaSO₄but chemicalreaction occurred between aluminium coupling agent and nano-BaSO₄surface groups.Results show that coMPared with stearic acid, aluminium coupling agent modified the besteffect. And we find optimum conditions of aluminium coupling agent modification: nanoBaSO₄content 1.0wt%, the reaction temperature is 80℃.3. From the cross-surface SEM observation of the PE/BaSO₄composite, there was nocrack or pore in the surface, nano-BaSO₄particles combined with PE matrix coMPact. Theresults showed that the nano-BaSO₄was modified by modifiers dispersed better thanuntreated nano-BaSO₄. The particle size of PE/AL-BaSO₄is about 100 nm. CoMPared withPE/SA-BaSO₄nanocomposites，the PE/AL-BaSO₄nanocomposites have better mechanicalproperties. The maximum tensile strength of nanocomposites was 11.87MPa, flexural strengthwas 6.61 MPa, and elongation rate was 66.78%.4. After accelerated-aging experiment, the tenslie strength and elongation at breakdecreased a slight. The tensile strength of nanocomposites only decreased 5-15% andelongation at break decreased 12-15%. However, the mechanical properties of thenanocomposites after accelerated-aging are still able to satisfy application of clinical. So it can be used for over 10 years.5. When the filler surface is modified by 1.0wt% aluminium coupling agent the tensilestrength increased about 10.4% relative to clinical product, and the elongation at breakincreases about 14.2%, flexural strength increases about 16.4%. And after accelerated-agingexperiment, the tenslie strength increases about 13.9% relative to clinical product, theelongation at break increases about 17.1%.